Homebrew PCBs

http://www.intertronics.co.uk/products/prodindx.htm

http://www.intertronics.co.uk/resource/guide1.pdf

Leon

hi,

Got all the materials yesterday, lexan plates, lots of other plastic  
scraps of various material,
and the titanium shaft (10mm).


Now i'm wondering how to assemble them to a preferrably working spray  
etcher ;-)

Initially i was sure i only want single-sided operation but right now it  
seems as if it would be easier construction-wise to make the container   
for two-sided operation. (i think i will opt not to implement the second  
sprayer right now and just drill the opening later if / when the first one  
works...)

I made a quick drawing (using my PCB layout software ;-) )
<http://groups.yahoo.com/group/Homebrew_PCBs/files/ST/sprayer01.gif>

Note that in the drawing two options for construction are shown, the lower  
edge is straight joined and the upper has a third piece inserted to allow  
the spray pipe to sit as far away from the board as possible.
The one version would be easier to manufacture, and i'm not sure the 40mm  
matter...?
Both edges will be made the same of course.

The material is 5mm lexan, with the yellow parts beeing some other  
plastic, i'm not sure yet...


I will drill a hole in the top lexan plate through which the sprayer tube  
can be inserted. the top yellow plate sits on this hole (with a seal).  
This should allow easy extraction/change of the sprayer tube for tests.

I will glue the lexan with silicone, as i have it, have used it before,  
and it possibly allows re-use of hte lexan should the whole affair fail ;-)

The plan is to assemble the tank, and do exhausting tests with water to  
find ideal spray nozzle pattern/size before filling it with etchant.

Let me know what you think, right now i can use every suggestion...

ST

Stefan
I remember you talking about having an issue with the etchant forming a 
vortex around the bottom of the pipes.
Originally I was thinking you should put a plate on the bottom of the 
pipe that was bigger than the vortex.  Took me a second or two to figure 
out that would just make things worse. 
Than the thought occurred to do the the opposite - constrain the fluid, 
and here are a couple of ways:
Use a plate that does not move, and that keeps the fluid from developing 
a vortex outside of the pipe.
Place crumpled plastic mesh at the base, that would induce a bunch of 
drag and slow any vortex.
Place plastic vanes that are lined up radially from the bearing out. 
If they go higher than the fluid, they would preclude a vortex from 
forming except in the space between them and the spinning tube, which 
can be minimized.
Richard

On Wed, 23 Mar 2005 22:03:06 -0800, RMustakos <rmustakos@...>  
wrote:

> Stefan
> I remember you talking about having an issue with the etchant forming a
> vortex around the bottom of the pipes.
> Originally I was thinking you should put a plate on the bottom of the
> pipe that was bigger than the vortex.  Took me a second or two to figure
> out that would just make things worse.
> Than the thought occurred to do the the opposite - constrain the fluid,
> and here are a couple of ways:
> Use a plate that does not move, and that keeps the fluid from developing
> a vortex outside of the pipe.
> Place crumpled plastic mesh at the base, that would induce a bunch of
> drag and slow any vortex.
> Place plastic vanes that are lined up radially from the bearing out.
> If they go higher than the fluid, they would preclude a vortex from
> forming except in the space between them and the spinning tube, which
> can be minimized.
> Richard


I think the vanes are the best idea. a spoon can stop a vortex in a coffe  
cup real fast...
will do..

ST

I have this RTV silicone meant for acrylic glass, it says on the packaging  
that it is good for polycarbonate.

Well, it doesn't cure. After opening it i found it looking dull and all  
strange, i actually made sure twice that it is silicone and not acrylic  
sealant.

After trying on a piece of lexan it doesn't cure at all (5 hours).

A sample of standard silicone shows a skin in a few minutes.

The manufactuing date is 11/2000.

What is wrong with it? is it too old? I have never encountered this  
problem, usually it cures inside the container.
I'm glad i did not use it without trying it first.

Please let me know if you know what is going on, and also if you happen to  
know if there is substantial difference in adhesion between silicone meant  
for acrylic glass and standard silicone.

thanks

ST

That looks like an impressive setup - especially for home use. As
someone who has worked around this type of equipment for 15 years - my
thoughts are you should put the entire machine in a secondary
tray/container. Because eventually - all etchers will eventually leak.
It may take a few years, but eventually it will happen to all
ethchers. I'd use a large try that's a couple of inches deep. Ideally,
it should be large enough to hold the entire volume of etchant in your
machine.

In response to your question about silicone sealant - some types
require 24-48 hours to set. But there may be a chance it is too old.
Most of the GE brand silicone RTV sealants I've used have a 2 or 3
year shelf life.

Hi,

Of course it will be in a secondary container ;-).
I have found a nice deep plastic tray which i already used with the last  
etcher.
(It is also useful to store other stuff, like replenishing chemicals and  
analyzing gear.)

thanks

ST



On Fri, 25 Mar 2005 03:32:55 -0000, fab4442003 <fab4442003@...>  
wrote:

>
> That looks like an impressive setup - especially for home use. As
> someone who has worked around this type of equipment for 15 years - my
> thoughts are you should put the entire machine in a secondary
> tray/container. Because eventually - all etchers will eventually leak.
> It may take a few years, but eventually it will happen to all
> ethchers. I'd use a large try that's a couple of inches deep. Ideally,
> it should be large enough to hold the entire volume of etchant in your
> machine.
> In response to your question about silicone sealant - some types
> require 24-48 hours to set. But there may be a chance it is too old.
> Most of the GE brand silicone RTV sealants I've used have a 2 or 3
> year shelf life.

Guys,

things are not going well with the sprayer..

The acrylic silicone is definitely trash, the standard silicone doesn't  
stick well (at all) on the lexan.
I have tried everything, roughening the surface, cleaning well, ... it  
still comes off way too easy.

I can go and buy new silicone for acrylic glass, but i'm not too sure it  
will hold all that much better.

welding, i'm kind of reluctant because it is a very final thing, changes  
on the tank will be almost impossible.
Also, i have not tried yet how hard welding lexan is.

I'm thinking about other glues, but i would have preferred silicone  
because one can easily fill gaps and make thick beads.

Didn't expect _AT ALL_ that the gluing will be so much trouble.

ST

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, March 25, 2005 10:49 AM
Subject: Re: [Homebrew_PCBs] Re: sprayer tank construction


>
> Guys,
>
> things are not going well with the sprayer..
>
> The acrylic silicone is definitely trash, the standard silicone doesn't
> stick well (at all) on the lexan.
> I have tried everything, roughening the surface, cleaning well, ... it
> still comes off way too easy.
>
> I can go and buy new silicone for acrylic glass, but i'm not too sure it
> will hold all that much better.
>
> welding, i'm kind of reluctant because it is a very final thing, changes
> on the tank will be almost impossible.
> Also, i have not tried yet how hard welding lexan is.
>
> I'm thinking about other glues, but i would have preferred silicone
> because one can easily fill gaps and make thick beads.
>
> Didn't expect _AT ALL_ that the gluing will be so much trouble.

Some of the low-cost bubble etching tanks are made from PVC.

Leon

On Fri, 25 Mar 2005 11:18:08 -0000, Leon Heller  
<leon.heller@...> wrote:

>
> Some of the low-cost bubble etching tanks are made from PVC.
> Leon


Ok Leon, thank you.

I have kind of bought that lexan already and i want it transparent.

ST

Most commercial etchers are made from Polypropylene (which can
withstand higher temperatures than PVC) and they're usually welded
together. There's at least one brand I've seen whose tank is molded
out of a single sheet of Polypropylene - so the tank won't leak. Most
have see-thru Lexan (or a similar plastic) top covers.

hi,

while testing the silicone for the tank i tried to coat a sheet of paper  
with it for transfer.
Simply spread with a piece of plastic, it doesn't wrinkle the paper like  
water.

Result:
the transfer is smudged (a lot) but one can peel the coated paper off  
without anything left on the coated paper
(no soaking).

The first result is too smudged (i let it through the fuser twice and the  
second pass shifted the paper i think), however, i think this is something  
that should be examined more closely.

ST

Hi,

had to have a second try.
relieved the pressure on the fuser rollers a bit, and made only one run.


1000% the sharpest and best toner transfer i have EVER seen with NO  
soaking, just peeling of the paper!!!

Good, solid, scratch resistant transfer.

I might well have come across something here that will make my PCB making  
a lot easier.
(Just think about it, no soaking, that means no rubbing an no limitation  
in minimum spacing because there is residue..)

Also, the transfer looks very, very sharp to me (must test further).
Maybe the even surface of the silicone is better than rough paper.  
(spreading is unknown, but the edges are sharp so it doesn't seem much).

I'm glad i tried a second time. After the first one was so bad i might  
just have forgotten about it.


Well, tests will follow, but i must do something else now.
Pleas try yourself too.


ST

Stefan:

I'm assuming you used the silicone sealant from a squeeze tube -  You 
might try using the spray-on silicone lubricant on a sheet.  Might be 
easier to apply.  Might even work.

  Norm
Stefan Trethan wrote:

>Hi,
>
>had to have a second try.
>relieved the pressure on the fuser rollers a bit, and made only one run.
>
>
>1000% the sharpest and best toner transfer i have EVER seen with NO  
>soaking, just peeling of the paper!!!
>
>Good, solid, scratch resistant transfer.
>
>I might well have come across something here that will make my PCB making  
>a lot easier.
>(Just think about it, no soaking, that means no rubbing an no limitation  
>in minimum spacing because there is residue..)
>
>Also, the transfer looks very, very sharp to me (must test further).
>Maybe the even surface of the silicone is better than rough paper.  
>(spreading is unknown, but the edges are sharp so it doesn't seem much).
>
>I'm glad i tried a second time. After the first one was so bad i might  
>just have forgotten about it.
>
>
>Well, tests will follow, but i must do something else now.
>Pleas try yourself too.
>
>
>ST
>
>
>
>Be sure to visit the group home and check for new Bookmarks and files:
>http://groups.yahoo.com/group/Homebrew_PCBs 
>Yahoo! Groups Links
>
>
>
> 
>
>
>
>
>
>  
>



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On Fri, 25 Mar 2005 09:07:28 -0800, Norm Stewart <normstewart@...>  
wrote:

> Stefan:
> I'm assuming you used the silicone sealant from a squeeze tube -  You
> might try using the spray-on silicone lubricant on a sheet.  Might be
> easier to apply.  Might even work.
>  Norm


Hi,

lubricant as in silicone oil isn't going to work as it must cure and  
harden before use.

another mail with details and a test photo will follow in a few minutes.

ST

ok,

got back to testing that...

the silicone is simply spread into a very thin layer (i used a floppy disk  
as sqeegee).
The amount of silicon used is tiny, i do not consider it much of a cost  
factor (compared to buying inkjet paper it is sure cheaper).
My experiments so far have not shown slight unevenness to be a problem.

After drying (thin layer cures quickly) you simply print on it like on  
paper.

Then it is transferred with the fuser liek any other transfer. Instead of  
soaking you let it cool (to avoid the toner beeing still soft) and just  
peel of the paper. It comes off very easily and no toner is on the paper,  
nor is there any silicone on the PCB.

Ready.

see a test here, note that is the third transfer i made with silicone  
paper, 1mb:
<http://www.trethan.at.tf/pub/img1/pcbsil.jpg>


The spreading is there, severe, maybe.
I have used darkest toner setting, less may help.
However, the quality is the same if not better than my best transfer with  
inkjet paper and this one need not be rubbed or anything.
No problems with paper between traces or even inside drill holes and NO  
paper residue with component legend.


The preparing of the paper is an additional step i admit, but it is far  
less work than soaking and rubbing and can be done at any time preparing  
many sheets.

I tried baking paper in the past, but the toner is brushed off too easily.  
The silicone coated paper feels not slick, it is kind of sticky, but seems  
to realease the toner readily.

that method will certainly make PCB making easier for me. I hope to soon  
here from your results too.

Now, while the silicone problems with the lexan tank made me find this  
out, which is great, i still would hope to find a way to make that tank.  
standard silicone doesn't stick _at all_ on lexan. not sure what to do  
next....

ST

Next question - have you tried re-using a sheet?  Make one really good 
transfer sheet and use it forever?

Norm
Stefan Trethan wrote:

>ok,
>
>got back to testing that...
>
>the silicone is simply spread into a very thin layer (i used a floppy disk  
>as sqeegee).
>The amount of silicon used is tiny, i do not consider it much of a cost  
>factor (compared to buying inkjet paper it is sure cheaper).
>My experiments so far have not shown slight unevenness to be a problem.
>  
>



-- 
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.8.2 - Release Date: 3/25/2005

On Fri, 25 Mar 2005 10:02:06 -0800, Norm Stewart <normstewart@...>  
wrote:

>
> Next question - have you tried re-using a sheet?  Make one really good
> transfer sheet and use it forever?
> Norm


I have thought about that, and i think it would be possible for several  
transfers at least as all toner comes off.
However, i often make small PCBs and the edges leave impressions in the  
paper while fusing, which might compromise print quality.

A really good sheet is not really needed it seems. the ones i made were  
quick and easy to make and worked very well.
I do not think there is much gain in re-use, as the amount of silicone  
needed is very small and because any paper can be used it is cheaper than  
inkjet paper.

ST

Is this just silicone caulk you are using?  Like what you would use on a
bathtub?  If I understand what you are doing, just put a glob on the paper
and then scrape it around til the whole sheet has been coated, how much is
left on the paper?  Perhaps some pictures of the process coating the paper
so we can see how much you are using, and how much is left on the paper.

Are there any possible side effects to the printer?  I would hate to ruin
a drum, or worse a printer.

Ed

On Fri, 25 Mar 2005 10:26:01 -0800 (PST), Ed Okerson <ed@...>  
wrote:

> Is this just silicone caulk you are using?  Like what you would use on a
> bathtub?  If I understand what you are doing, just put a glob on the  
> paper
> and then scrape it around til the whole sheet has been coated, how much  
> is
> left on the paper?  Perhaps some pictures of the process coating the  
> paper
> so we can see how much you are using, and how much is left on the paper.
> Are there any possible side effects to the printer?  I would hate to ruin
> a drum, or worse a printer.
> Ed


Yes, the bathtub stuff ;-) (I used the transparent acetic acid stuff)

I do exactly as you say and scrape it as thin as possible. I try to keep  
the surface glossy (if you scrape very hard it becomes dull as the paper  
is exposed, but i don't know if that harms.)
If you don't go to the edges of the paper it is easier (no mess on table)  
and i rarely have a pcb that fills the sheet.

I will make pictures at some point, perhaps, but they won't say too much i  
think.

Possible effects on the printer, well, if it is cured i would not expect  
any.
it does not come off easily, and it does not melt, and it is very soft, so  
i can't see why it might damage the printer.

ST

Those transfers in  your picture look great!
What printer are you using? How many dpi?


--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
> ok,
> 
> 
> see a test here, note that is the third transfer i made with
silicone  

> paper, 1mb:
> <http://www.trethan.at.tf/pub/img1/pcbsil.jpg>
> 
>

On Fri, 25 Mar 2005 19:41:14 -0000, javaguy11111 <javaguy11111@...>  
wrote:

>
> Those transfers in  your picture look great!
> What printer are you using? How many dpi?
>


600dpi lexmark 412.

I found that under 5mil is impossible with my current etcher anyway  
because of underetching.
3.33mil will not produce a continous line after etching. (which means the  
transfer is no loger my current limit ;-) ).

The silicone doesn't produce better quality than inkjet paper, but it  
makes things MUCH easier and makes small spaces possible without paper  
residue preventing them beeing etched properly.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" <leon.heller@d...>
wrote:
> Some of the low-cost bubble etching tanks are made from PVC.

I have had some long conversations with my local plastics guy over the
past few days, and he tells me that lexan, plexiglas, polycarbonate
are not good in constant contact with chemicals.

That PVC and it's variants, and styrene have good water, alcohol, and
chemical resistance.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "Steve" <alienrelics@y...> wrote:
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" <leon.heller@d...>
> wrote:
> > Some of the low-cost bubble etching tanks are made from PVC.
> 
> I have had some long conversations with my local plastics guy over the
> past few days, and he tells me that lexan, plexiglas, polycarbonate
> are not good in constant contact with chemicals.
> 
> That PVC and it's variants, and styrene have good water, alcohol, and
> chemical resistance.

And the best methods to making them watertight are welding or the
appropriate solvent based cement.

Steve Greenfield

On Fri, 25 Mar 2005 22:09:10 -0000, Steve <alienrelics@...> wrote:

>
> --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" <leon.heller@d...>
> wrote:
>> Some of the low-cost bubble etching tanks are made from PVC.
> I have had some long conversations with my local plastics guy over the
> past few days, and he tells me that lexan, plexiglas, polycarbonate
> are not good in constant contact with chemicals.
> That PVC and it's variants, and styrene have good water, alcohol, and
> chemical resistance.
> Steve Greenfield


WHAT? HELP!!
You say all my humongous efforts are for nought?

I fear i must despair here, no working glue, no good for chemicals, i can  
just about throw my newly bought lexan away.

Any idea what will happen to the lexan in CuCl?

I'm at my wits end with that stupid sprayer. I have wasted hours (and  
money!) and i'm still at square one (actually behind it really..).

I want(-ed) a transparent tank to see things clearly, especially spray  
pattern and such.

I really needed that unexpected success with the silicone paper today,  
otherwise i'd go pretty mad pretty soon.
Oh well, i'll sleep over it (again), i'm sure things look just as bad  
tomorrow.

ST

On Fri, 25 Mar 2005 22:12:44 -0000, Steve <alienrelics@...> wrote:

>
> And the best methods to making them watertight are welding or the
> appropriate solvent based cement.
> Steve Greenfield


what if i make the damn thing glass? I used that for the current tank and  
acetic acid silicone sticks like mad to it.
Of course the lid would need to be plastic, but it could be opaqe and  
screwed-down against a seal.


ST

How do you transfer the image to the board? Normally I've been using a
cloths iron (for 1-2 minutes) to heat the photopaper with image/board
and transfer the image, and then soaking/brushing the paper/board with
water until all of the paper is removed.

On Fri, 25 Mar 2005 22:57:32 -0000, fab4442003 <fab4442003@...>  
wrote:

>
> How do you transfer the image to the board? Normally I've been using a
> cloths iron (for 1-2 minutes) to heat the photopaper with image/board
> and transfer the image, and then soaking/brushing the paper/board with
> water until all of the paper is removed.
>


I use a fuser from a dead copier, but it will work with the iron too.
It is the same process but the soaking/brushing is no longer needed  
because the silicone doesn't allow the toner to fuse to it.
The paper can just be lifted off.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:

> Any idea what will happen to the lexan in CuCl?

I'm told it will develop cracks or "crazing" and eventually start leaking.

> I want(-ed) a transparent tank to see things clearly, especially spray  
> pattern and such.

You can get transparent aluminum.... er, I mean transparent PVC and
styrene.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
> On Fri, 25 Mar 2005 22:12:44 -0000, Steve <alienrelics@y...> wrote:
> 
> >
> > And the best methods to making them watertight are welding or the
> > appropriate solvent based cement.
> > Steve Greenfield
> 
> 
> what if i make the damn thing glass? I used that for the current
tank and  
> acetic acid silicone sticks like mad to it.
> Of course the lid would need to be plastic, but it could be opaqe and  
> screwed-down against a seal.

I recall early on someone saying that you must use a specific kind of
caulk made for fishtanks, that normal silicone sealant will experience
"crawling". IE, the water in constant contact slowly leaches between
the silicone and the glass, ultimately breaking the seal.

Steve Greenfield

On Sat, 26 Mar 2005 03:56:26 -0000, Steve <alienrelics@...> wrote:

>
> I recall early on someone saying that you must use a specific kind of
> caulk made for fishtanks, that normal silicone sealant will experience
> "crawling". IE, the water in constant contact slowly leaches between
> the silicone and the glass, ultimately breaking the seal.
> Steve Greenfield


while that is true, the time constants involved are very big.
Fish tanks with standard silicone have held for 20yrs and longer.
(I have read all the fush tank FAQs).

ST

On Sat, 26 Mar 2005 03:55:10 -0000, Steve <alienrelics@...> wrote:

>
> You can get transparent aluminum.... er, I mean transparent PVC and
> styrene.
> Steve Greenfield


you get transparent aluminium too, in some countries aluminum foil is so  
thin light shines through ;-)

ST

Hi,

I will make the tank from glass 'cause Steve says lexan is no good (thanks  
by the way, would have been bad if it cracked after some time.).

Found some 5mm glass, will use it for bottom and sides, the top will maybe  
be phenolic board (not PCB, 5mm thick variety).


The 5mm glas will be sturdy enough, and i don't think it will break even  
if some part goes flying inside. Also, it will be heavy and help dampening  
any vibrations.
I reckon a transparent top is not all that useful, after all the spray  
would cause droplets to form which would obscure the view pretty soon. I  
will use the sides to view which get cleaned by the spraying etchant.

Right now i wonder what material i'm gonna use for the bearings (of the  
ones i have, i'm not buying teflon right now) and how to affix it to the  
glass floor....
Must identify the materials i have, i think there are chip burn tests and  
similar methods which are reasonably easy to do.


thanks

ST

After seeing Stefan's results I had to try the silicone paper idea
myself. The silicone I used was GE Silicone I Clear Kitchen and Bath
which I bought at Lowes.

I did make a few changes to the process. First I used transparency
instead of paper so I could see what was going on. Also in an attempt
to get as even a coating as possible I taped down a few extra pieces
of tranparency for my putty knife to ride over to get an even
thickness. I also used transparency because I wanted to rinse down the
silicone to remove any residual acetic acid from the curing. I am not
sure what that may do to the drum or fuser.

My results were not as good as Stefan's. First the coating did not
come out as smooth as I would like to have seen it. It tended to have
some ripples and bubbles in it. When I ran it through my HP 1300 laser
printer I get a lot of toner dust scattered around. The image itself
looked okay. 

I then ran my silicone coated transparency through my laminator with
the circuit and most of my image transferred along with the toner
dust. The areas that did not transfer tend be in the areas where I had
ripples or bubbles. 

For me the biggest problem is all the toner particles that were
scattered around. I would not have been able to etch a board in that
condition.

Still I think the technique shows alot of promise. I probably will not
do anymore experiments today, but things I would try different is to
use a scotch tape spacer to try to get the coating thinner and also
try differnent spreading techniques to try to get the coating more
even. I also wonder if there is any kind of solvent to thin out the
thick silicone. That may allow for a more even coating.


--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
> Hi,
> 
> had to have a second try.
> relieved the pressure on the fuser rollers a bit, and made only one
run.
> 
> 
> 1000% the sharpest and best toner transfer i have EVER seen with NO
 
> soaking, just peeling of the paper!!!
> 
> Good, solid, scratch resistant transfer.
> 
> I might well have come across something here that will make my PCB
making  
> a lot easier.
> (Just think about it, no soaking, that means no rubbing an no
limitation  
> in minimum spacing because there is residue..)
> 
> Also, the transfer looks very, very sharp to me (must test further).
> Maybe the even surface of the silicone is better than rough paper.  
> (spreading is unknown, but the edges are sharp so it doesn't seem
much).
> 
> I'm glad i tried a second time. After the first one was so bad i
might  

> just have forgotten about it.
> 
> 
> Well, tests will follow, but i must do something else now.
> Pleas try yourself too.
> 
> 
> ST

On Sat, 26 Mar 2005 22:40:06 -0000, javaguy11111 <javaguy11111@...>  
wrote:

>
> For me the biggest problem is all the toner particles that were
> scattered around. I would not have been able to etch a board in that
> condition.
> Still I think the technique shows alot of promise. I probably will not
> do anymore experiments today, but things I would try different is to
> use a scotch tape spacer to try to get the coating thinner and also
> try differnent spreading techniques to try to get the coating more
> even. I also wonder if there is any kind of solvent to thin out the
> thick silicone. That may allow for a more even coating.


I have not observed any of that toner, dunno where it comes from.

The acetic acid is a valid point, maybe neutral curing silicone would be  
better?
I do not expect problems at the fuser (teflon coat) but i do not know  
about the drum i admit.

You can get thinner silicone, for moulding, but it is not properly sticky  
i fear. Thinning is very hard but not impossible i think i remember.

I didn't use any spacer, just spread it out very thin with the slightly  
rounded edge of a floppy disc.


ST

> I didn't use any spacer, just spread it out very thin with the
slightly  
> rounded edge of a floppy disc

5.25 inch or 3.5 inch floppy?

The transparency is non-absorbent - the silicone will bead up on the 
surface.  Paper will absorb some of the silicone -allow for a thinner, 
smoother, better bond.  Just my thoughts  - -

Norm

>  
>
>>For me the biggest problem is all the toner particles that were
>>scattered around. I would not have been able to etch a board in that
>>condition.
>>Still I think the technique shows alot of promise. I probably will not
>>do anymore experiments today, but things I would try different is to
>>use a scotch tape spacer to try to get the coating thinner and also
>>try differnent spreading techniques to try to get the coating more
>>even. I also wonder if there is any kind of solvent to thin out the
>>thick silicone. That may allow for a more even coating.
>>    
>>
>
>
>I have not observed any of that toner, dunno where it comes from.
>
>The acetic acid is a valid point, maybe neutral curing silicone would be  
>better?
>I do not expect problems at the fuser (teflon coat) but i do not know  
>about the drum i admit.
>
>You can get thinner silicone, for moulding, but it is not properly sticky  
>i fear. Thinning is very hard but not impossible i think i remember.
>
>I didn't use any spacer, just spread it out very thin with the slightly  
>rounded edge of a floppy disc.
>
>
>ST
>
>
>
>Be sure to visit the group home and check for new Bookmarks and files:
>http://groups.yahoo.com/group/Homebrew_PCBs 
>Yahoo! Groups Links
>
>
>
> 
>
>
>
>
>
>  
>



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javaguy11111 wrote:

> My results were not as good as Stefan's. First the coating did not
> come out as smooth as I would like to have seen it.

Likely due to the texture of the paper acting to self-level
the silicone film.  The paper is also much more compressible
than the transparency film which compensates for irregularities
in both the knife and surface upon which the film/paper rests.

I have heard of success using printer label backer sheet for
this same purpose.  Is there some reason this is not a
viable solution?  It would seem quite cost effective.


-- 
uhmgawa@...        www.gnu.org

I do have some laser printer labels and had thought of the backer
sheet. However I was not sure if it was silicone or maybe some kind of
wax. 

In doing some searching I did also see references to silicone coated
paper being sold by places that sell transfer sheets for things like
t-shirts and cups. 

It makes me wonder why the usual PCB toner transfer venders are not
selling something similar. The PNP Blue that I normally use does not
appear to be silicone based.


--- In Homebrew_PCBs@yahoogroups.com, uhmgawa <uhmgawa@m...> wrote:

> javaguy11111 wrote:
> 
> > My results were not as good as Stefan's. First the coating did not
> > come out as smooth as I would like to have seen it.
> 
> Likely due to the texture of the paper acting to self-level
> the silicone film.  The paper is also much more compressible
> than the transparency film which compensates for irregularities
> in both the knife and surface upon which the film/paper rests.
> 
> I have heard of success using printer label backer sheet for
> this same purpose.  Is there some reason this is not a
> viable solution?  It would seem quite cost effective.
> 
> 
> -- 
> uhmgawa@m...        www.gnu.org

I will also mention that there is a silicone coated 
baking paper called Exopap. It is rather pricey. Anyone know a 
really serious cook or chef?

Here is a site

<http://www.culinarycookware.com/catalog.asp?catid=4400&prodid=73200>

--- In Homebrew_PCBs@yahoogroups.com, "javaguy11111"
<javaguy11111@y...> wrote:
> 
> I do have some laser printer labels and had thought of the backer
> sheet. However I was not sure if it was silicone or maybe some kind
of
> wax. 
> 
> In doing some searching I did also see references to silicone coated
> paper being sold by places that sell transfer sheets for things like
> t-shirts and cups. 
> 
> It makes me wonder why the usual PCB toner transfer venders are not
> selling something similar. The PNP Blue that I normally use does not
> appear to be silicone based.
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com, uhmgawa <uhmgawa@m...> wrote:
> > javaguy11111 wrote:
> > 
> > > My results were not as good as Stefan's. First the coating did
not

> > > come out as smooth as I would like to have seen it.
> > 
> > Likely due to the texture of the paper acting to self-level
> > the silicone film.  The paper is also much more compressible
> > than the transparency film which compensates for irregularities
> > in both the knife and surface upon which the film/paper rests.
> > 
> > I have heard of success using printer label backer sheet for
> > this same purpose.  Is there some reason this is not a
> > viable solution?  It would seem quite cost effective.
> > 
> > 
> > -- 
> > uhmgawa@m...        www.gnu.org

On Sun, 27 Mar 2005 03:29:07 -0000, fab4442003 <fab4442003@...>  
wrote:

>
>> I didn't use any spacer, just spread it out very thin with the
> slightly
>> rounded edge of a floppy disc
> 5.25 inch or 3.5 inch floppy?


3.5, have no 5.25 left any more.

ST

On Sun, 27 Mar 2005 07:40:22 -0000, javaguy11111 <javaguy11111@...>  
wrote:

>
> I do have some laser printer labels and had thought of the backer
> sheet. However I was not sure if it was silicone or maybe some kind of
> wax.
> In doing some searching I did also see references to silicone coated
> paper being sold by places that sell transfer sheets for things like
> t-shirts and cups.
> It makes me wonder why the usual PCB toner transfer venders are not
> selling something similar. The PNP Blue that I normally use does not
> appear to be silicone based.


Label paper and backing paper did not work for me. The surface is too  
slick and the toner falls off/is wiped off by the printer mechanisms  
before i can use it. Also impossible to align without destruction.

The silicone coated paper is not slick, it is sticky. if you have two  
silicone coated sheets and stick them together with the silicone side they  
stay that way. (you can not slide them against each other, or your finger  
over the silicone for that matter).

Because of this the printout is still rather solid. you can scratch away  
the toner with your fingernail if you try, but normal handling will not  
harm it. I have not tried how difficult alignment of 2-sided is myde by  
the stickyness.

ST

How about using silicone mold release spray? (The composities 
industry uses it by the "boat"load<G>)

Not oily, and dries hard Any place that sells fiberglas (FRP) 
supplies should have it.

Hope this helps,

Ballendo

--- In Homebrew_PCBs@yahoogroups.com, "javaguy11111" 
<javaguy11111@y...> wrote:
> 
> After seeing Stefan's results I had to try the silicone paper idea
> myself. The silicone I used was GE Silicone I Clear Kitchen and Bath
> which I bought at Lowes.
> 
> I did make a few changes to the process. First I used transparency
> instead of paper so I could see what was going on. Also in an 
attempt
> to get as even a coating as possible I taped down a few extra pieces
> of tranparency for my putty knife to ride over to get an even
> thickness. I also used transparency because I wanted to rinse down 
the
> silicone to remove any residual acetic acid from the curing. I am 
not
> sure what that may do to the drum or fuser.
> 
> My results were not as good as Stefan's. First the coating did not
> come out as smooth as I would like to have seen it. It tended to 
have
> some ripples and bubbles in it. When I ran it through my HP 1300 
laser
> printer I get a lot of toner dust scattered around. The image itself
> looked okay. 
> 
> I then ran my silicone coated transparency through my laminator with
> the circuit and most of my image transferred along with the toner
> dust. The areas that did not transfer tend be in the areas where I 
had
> ripples or bubbles. 
> 
> For me the biggest problem is all the toner particles that were
> scattered around. I would not have been able to etch a board in that
> condition.
> 
> Still I think the technique shows alot of promise. I probably will 
not
> do anymore experiments today, but things I would try different is to
> use a scotch tape spacer to try to get the coating thinner and also
> try differnent spreading techniques to try to get the coating more
> even. I also wonder if there is any kind of solvent to thin out the
> thick silicone. That may allow for a more even coating.
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
> <stefan_trethan@g...> wrote:
> > Hi,
> > 
> > had to have a second try.
> > relieved the pressure on the fuser rollers a bit, and made only 
one
> run.
> > 
> > 
> > 1000% the sharpest and best toner transfer i have EVER seen with 
NO
>  
> > soaking, just peeling of the paper!!!
> > 
> > Good, solid, scratch resistant transfer.
> > 
> > I might well have come across something here that will make my PCB
> making  
> > a lot easier.
> > (Just think about it, no soaking, that means no rubbing an no
> limitation  
> > in minimum spacing because there is residue..)
> > 
> > Also, the transfer looks very, very sharp to me (must test 
further).
> > Maybe the even surface of the silicone is better than rough 
paper.  

> > (spreading is unknown, but the edges are sharp so it doesn't seem
> much).
> > 
> > I'm glad i tried a second time. After the first one was so bad i
> might  
> > just have forgotten about it.
> > 
> > 
> > Well, tests will follow, but i must do something else now.
> > Pleas try yourself too.
> > 
> > 
> > ST

On Sun, 27 Mar 2005 11:01:46 -0000, ballendo <ballendo@...> wrote:

>
> How about using silicone mold release spray? (The composities
> industry uses it by the "boat"load<G>)
> Not oily, and dries hard Any place that sells fiberglas (FRP)
> supplies should have it.
> Hope this helps,
> Ballendo


I think it will not be sticky enough.

ST

take alook at this site.

 mebo.

http://www.paperandfilm.com/index.asp?PageAction=Custom&ID=57

On Sun, 27 Mar 2005 22:28:12 -0000, pebo festus <mebo31@...> wrote:

> take alook at this site.
> mebo.
> http://www.paperandfilm.com/index.asp?PageAction=Custom&ID=57
>


not sure if they'd bother with small amounts, and not sure i'd want to pay  
a lot if i can make it cheap.

ST

I've tried the label backing too, with mixed results. I agree with 
Stefan, the surface is just too slick and the toner is easily scaped 
off during handling.

But if you think about it, that level of slickness is the 
requirement for label release. We do not need such slickness for 
laser transfer. So the question is, how to increase the tackiness of 
the label backing.

Having a couple of teenage daughters, there is plenty of hair spray 
in my house. I just put a light mist coat on some label backing. 
There is definately a change in surface texture, a little rough and 
grabby.

It'll b intresting to see if it will run through my old Laserjet 
IIIP+.

Will keep you posted.

Myc


--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
> On Sun, 27 Mar 2005 07:40:22 -0000, javaguy11111 
<javaguy11111@y...>  
> wrote:
> 
> >
> > I do have some laser printer labels and had thought of the backer
> > sheet. However I was not sure if it was silicone or maybe some 
kind of
> > wax.
> > In doing some searching I did also see references to silicone 
coated
> > paper being sold by places that sell transfer sheets for things 
like
> > t-shirts and cups.
> > It makes me wonder why the usual PCB toner transfer venders are 
not
> > selling something similar. The PNP Blue that I normally use does 
not
> > appear to be silicone based.
> 
> 
> Label paper and backing paper did not work for me. The surface is 
too  
> slick and the toner falls off/is wiped off by the printer 
mechanisms  
> before i can use it. Also impossible to align without destruction.
> 
> The silicone coated paper is not slick, it is sticky. if you have 
two  
> silicone coated sheets and stick them together with the silicone 
side they  
> stay that way. (you can not slide them against each other, or your 
finger  
> over the silicone for that matter).
> 
> Because of this the printout is still rather solid. you can 
scratch away  
> the toner with your fingernail if you try, but normal handling 
will not  
> harm it. I have not tried how difficult alignment of 2-sided is 
myde by  

> the stickyness.
> 
> ST

Stefan Trethan wrote:
> After drying (thin layer cures quickly) you simply print on it like on  
> paper.
> 

   Hadn't checked in here in a while, have a board that'll need to get made soon 
and this looks good so will have to give it a try.  Everything that is easier is 
great, you can always fix a little smudging later.

> Now, while the silicone problems with the lexan tank made me find this  
> out, which is great, i still would hope to find a way to make that tank.  
> standard silicone doesn't stick _at all_ on lexan. not sure what to do  
> next....
> 

     Can't remember which it is off hand that is easier to bend with heat, the 
carbonate or acrylic, but find that out again and get the easier one.  Make a 
rectangular sheet that is your larger 2 sides and bottom all as one piece. 
Table saw a 1/4" groove down each longer side, maybe 1/4"-1/2" in and like 1/3 
through the sheet, with 1/4" sheet.  Two folds to bend up the larger sides, and 
the groove will hold the smaller sides, greatly increasing the surface area and 
decreasing chance of leaks.  Use the welding type glue not silicone, with the 
extra surface area you shouldn't have a problem.  Might find some other glue 
that will stick ok and put a fillet on the outside of the joint, simply as a 
physical block to slow any leaks just in case it does spring one.  If your slot 
is tight to the inserted sides I don't think you'll get any leaks after just the 
weld glue anyway though, I've seen joints like this and they are very good. 
Keeping the corners a bit rounded is best, make it more of a flat bottom U shape 
than right angles and it should be good.

Alan

On Sun, 27 Mar 2005 22:55:34 -0000, mycroft2152 <mycroft2152@...>  
wrote:

>
> But if you think about it, that level of slickness is the
> requirement for label release. We do not need such slickness for
> laser transfer. So the question is, how to increase the tackiness of
> the label backing.


by using silicone adhesive instead ;-)

Not sure what material hairspray is, but for me there are many variables.  
Will it survive the fuser? will it transfer to the copper and make it  
useless?

I will definitely head in the silicone direction some more.
All my neutral-curing silicone is old and doesn't cure any more, so i will  
get fresh and try it, there shouldn't be any acetic acid. Anyone know if  
it releases any possibly harmful substances when curing? But then i don't  
even know if the acetic acid is a problem.

ST

mycroft2152 wrote:

> It'll b intresting to see if it will run through my old Laserjet 
> IIIP+.
> 


   Hairspray is potato rocket fuel, so let it dry well and back up some just in 
case..

   The back side of most label backing sheets is also somewhat slick, I have 
wondered before if some particular label company might have the right 
combination if the back side is used.

Alan

mycroft2152 wrote:
> 
> 
> Having a couple of teenage daughters, there is plenty of hair spray 
> in my house. I just put a light mist coat on some label backing. 
> There is definately a change in surface texture, a little rough and 
> grabby.
> 
> It'll b intresting to see if it will run through my old Laserjet 
> IIIP+.
> 
> Will keep you posted.

You are more likely to keep yourself pasted :)

Hairspray is frequently made of PVA or PVP adhesive - much the same as 
white woodworking glue - in an alcohol carrier. I cant see that doing 
your printer any good at all. Come to think of it, most girls I have 
explained that to were less sure about using it on their hair as well.

Don't take my word for it..

http://antoine.frostburg.edu/chem/senese/101/consumer/faq/hairspray-ingredients.shtml

Pete Harrison
http://micromouse.cannock.ac.uk/

I make heat pressed Tshirts, mousepads, and such.

Look for siliconized baking sheets. Cost me $3.50 for a long 8.5 inch
wide roll from JoAnn's Crafts. There's also an ironing release sheet
from a company called Heat 'n Bond but it's more expensive.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "javaguy11111"
<javaguy11111@y...> wrote:

> 
> I will also mention that there is a silicone coated 
> baking paper called Exopap. It is rather pricey. Anyone know a 
> really serious cook or chef?
> 
> Here is a site
> 
> <http://www.culinarycookware.com/catalog.asp?catid=4400&prodid=73200>
> 
> --- In Homebrew_PCBs@yahoogroups.com, "javaguy11111"
> <javaguy11111@y...> wrote:
> > 
> > I do have some laser printer labels and had thought of the backer
> > sheet. However I was not sure if it was silicone or maybe some kind
> of
> > wax. 
> > 
> > In doing some searching I did also see references to silicone coated
> > paper being sold by places that sell transfer sheets for things like
> > t-shirts and cups. 
> > 
> > It makes me wonder why the usual PCB toner transfer venders are not
> > selling something similar. The PNP Blue that I normally use does not
> > appear to be silicone based.
> > 
> > 
> > --- In Homebrew_PCBs@yahoogroups.com, uhmgawa <uhmgawa@m...> wrote:
> > > javaguy11111 wrote:
> > > 
> > > > My results were not as good as Stefan's. First the coating did
> not
> > > > come out as smooth as I would like to have seen it.
> > > 
> > > Likely due to the texture of the paper acting to self-level
> > > the silicone film.  The paper is also much more compressible
> > > than the transparency film which compensates for irregularities
> > > in both the knife and surface upon which the film/paper rests.
> > > 
> > > I have heard of success using printer label backer sheet for
> > > this same purpose.  Is there some reason this is not a
> > > viable solution?  It would seem quite cost effective.
> > > 
> > > 
> > > -- 
> > > uhmgawa@m...        www.gnu.org

That is something else entirely. It is a plastisol (or something like
that) thin sheet on a sheet of release paper. The ink or toner sticks
to it, and ironing or heat press bonds it to the Tshirt and
encapsulates the ink.

You'd end up with a sheet of copper completely coated regardless of
where the ink or toner went.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "pebo festus" <mebo31@y...> wrote:

> 
> take alook at this site.
> 
>  mebo.
> 
> http://www.paperandfilm.com/index.asp?PageAction=Custom&ID=57

Has anyone tried blank C1S (coated 1 side) paper that is used in the 
printing industry for things like food can labels and glossy magazine 
pages (C2S)?

On Sun, 27 Mar 2005 19:35:10 -0500, Jason Giglio <jgiglio@...>  
wrote:

>
> Has anyone tried blank C1S (coated 1 side) paper that is used in the
> printing industry for things like food can labels and glossy magazine
> pages (C2S)?


yes, some do with good results, even printed paper.
But it still needs soaking.

ST

Slight problem with that paper in US: labels on A-size carrier paper 
have that bloody carrier paper diagonally precut in 1"" strips...Mike

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
> On Sun, 27 Mar 2005 19:35:10 -0500, Jason Giglio <jgiglio@n...>  
> wrote:
> 
> >
> > Has anyone tried blank C1S (coated 1 side) paper that is used in 
the
> > printing industry for things like food can labels and glossy 
magazine

> > pages (C2S)?
> 
> 
> yes, some do with good results, even printed paper.
> But it still needs soaking.
> 
> ST

Looking trough my bookmarks I found a place where they sell 
special thermal transfer paper for pcbs.
They call it "Press and Peel Blue transfer film" here's the link:
 http://www.techniks.com/how_to.htm
 
It's not so expensive, 30$ for 20  8.5x11 sheets...
 
Dany
  _____  

De : mikezcnc [mailto:eemikez@...] 
Envoyé : 28 mars, 2005 17:17
À : Homebrew_PCBs@yahoogroups.com
Objet : [Homebrew_PCBs] Re: silicone coated paper - Another test



Slight problem with that paper in US: labels on A-size carrier paper 
have that bloody carrier paper diagonally precut in 1"" strips...Mike

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
> On Sun, 27 Mar 2005 19:35:10 -0500, Jason Giglio <jgiglio@n...>  
> wrote:
> 
> >
> > Has anyone tried blank C1S (coated 1 side) paper that is used in 
the
> > printing industry for things like food can labels and glossy 
magazine
> > pages (C2S)?
> 
> 
> yes, some do with good results, even printed paper.
> But it still needs soaking.
> 
> ST





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[Non-text portions of this message have been removed]

I googled again. look at this link.
mebo.

http://www.reynoldskitchens.com/reynoldskitchens/kitchenconnection/produ
cts/parchment_paper/index.asp

oops the link failed, look at silicone coated
parchment papers for cooking, i dont know how heavy
these are.

mebo 


		
__________________________________ 
Do you Yahoo!? 
Yahoo! Small Business - Try our new resources site!
http://smallbusiness.yahoo.com/resources/

I used that blue paper many years ago...prob around 6 or 7 to be 
exact...and it worked perfectly. back then I didn't have access to a 
laser printer! So a friend of mine scanned in the PCB artwork for me and 
laid it out on a graphics program to give me six on a half sheet (all 
that I had). I then ironed this on my radioshack pcb and viola! The kewl 
thing was that I didn't have to soak anything...just peeled.

l8r
Ric

Dany Tremblay wrote:

>Looking trough my bookmarks I found a place where they sell 
>special thermal transfer paper for pcbs.
>They call it "Press and Peel Blue transfer film" here's the link:
> http://www.techniks.com/how_to.htm
> 
>It's not so expensive, 30$ for 20  8.5x11 sheets...
> 
>Dany
>  _____  
>
>De : mikezcnc [mailto:eemikez@...] 
>Envoyé : 28 mars, 2005 17:17
>À : Homebrew_PCBs@yahoogroups.com
>Objet : [Homebrew_PCBs] Re: silicone coated paper - Another test
>
>
>
>Slight problem with that paper in US: labels on A-size carrier paper 
>have that bloody carrier paper diagonally precut in 1"" strips...Mike
>
>--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
><stefan_trethan@g...> wrote:
>  
>
>>On Sun, 27 Mar 2005 19:35:10 -0500, Jason Giglio <jgiglio@n...>  
>>wrote:
>>
>>    
>>
>>>Has anyone tried blank C1S (coated 1 side) paper that is used in 
>>>      
>>>
>the
>  
>
>>>printing industry for things like food can labels and glossy 
>>>      
>>>
>magazine
>  
>
>>>pages (C2S)?
>>>      
>>>
>>yes, some do with good results, even printed paper.
>>But it still needs soaking.
>>
>>ST
>>    
>>
>
>
>
>
>
>Be sure to visit the group home and check for new Bookmarks and files:
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>  
>



[Non-text portions of this message have been removed]

They are kind of thin. I thought I mentioned these before. I do Tshirt
heat transfers, and I use this as a top pressing sheet. It's just a
bit lighter feeling than regular laser paper.

You can also buy Heat N Bond pressing sheets, essentially the same
thing but in larger sheets.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, pebo festus <mebo31@y...> wrote:

> oops the link failed, look at silicone coated
> parchment papers for cooking, i dont know how heavy
> these are.
> 
> mebo

Just a quick update on things.

The sprayer tank is completed by now and in the testing stage with water.
Made it 5mm glass as discussed, holds together well.
The 50mm PVC tube i tried was out of round and no good.
The RC model motor i tried hadn't enough power, a 100W grinder was too  
weak too so today i fitted a larger 200W motor which is much better.
I'm using a empty silicone syringe for now as sprayer tube, it was there  
and seems to work ok. Must drill more holes and check pattern and  
uniformity.

No further tests with silicone paper so far as i'm basically without a  
etching tank right now, which is rather frightening really. (emptied the  
old one into bottles to fit the new one in the plastic tray.)
Oh well, if i had to make a PCB really desperately i could tray-etch it...

ST