Homebrew PCBs

Hi to everybody. I would like to start this thread to know/share 
different experiencies about dry-film processing (home-made lamination, 
imaging, developing, etc.)
Right now I am planning to build a laminator, uv-exposure unit, 
developing tanks, etc. (all of them DIY of course). After almost 15 
years using all other methods of PCB fabrication, including silk-
screening for whole big quantities of PCBs, I am tired of doing that 
kind of stuff again and I am planning to use the dry-film method (the 
only one that I should learned many years ago).
What about the ThinkTink supplies (resist and soldermask)?

On Thu, 25 Jan 2007, jcarlosmor wrote:

> Hi to everybody. I would like to start this thread to know/share
> different experiencies about dry-film processing (home-made lamination,
> imaging, developing, etc.)
> Right now I am planning to build a laminator, uv-exposure unit,
> developing tanks, etc. (all of them DIY of course). After almost 15
> years using all other methods of PCB fabrication, including silk-
> screening for whole big quantities of PCBs, I am tired of doing that
> kind of stuff again and I am planning to use the dry-film method (the
> only one that I should learned many years ago).
> What about the ThinkTink supplies (resist and soldermask)?

I don't have any experience with dry film, but I do have a metric buttload
of the stuff.  In a fit of madness several months ago, I bought an
unopened roll of AquaMer off Ebay.  I think my intention was to cut it
into smaller portions and sell it that way.  Anyhow, I don't think I'll
get to it any time soon, so if anyone wants it...


-- 
David Griffith
dgriffi@...

A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

--- In Homebrew_PCBs@yahoogroups.com, David Griffith <dgriffi@...> 
wrote:
>
> On Thu, 25 Jan 2007, jcarlosmor wrote:
> 

> 
> I don't have any experience with dry film, but I do have a metric 
> buttload
> of the stuff.  In a fit of madness several months ago, I bought an
> unopened roll of AquaMer off Ebay.  I think my intention was to 
> cut it
> into smaller portions and sell it that way.  Anyhow, I don't think 
> I'll
> get to it any time soon, so if anyone wants it...
> 

If you can break it up into reasonable sized chunks, you could 
probably sell it off right here in the group and at least break 
even. 

I'm not quite sure how much a 'metric buttload' is compared to 
an 'imperial buttload' but, unless the shipment came in a rail car, 
I'd think that this might be a good way to proceed.


Regards, Bob

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

From: "David Griffith" <dgriffi@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, January 25, 2007 4:57 AM
Subject: Re: [Homebrew_PCBs] someone with dry film processing experience?


> On Thu, 25 Jan 2007, jcarlosmor wrote:
>
>> Hi to everybody. I would like to start this thread to know/share
>> different experiencies about dry-film processing (home-made lamination,
>> imaging, developing, etc.)
>> Right now I am planning to build a laminator, uv-exposure unit,
>> developing tanks, etc. (all of them DIY of course). After almost 15
>> years using all other methods of PCB fabrication, including silk-
>> screening for whole big quantities of PCBs, I am tired of doing that
>> kind of stuff again and I am planning to use the dry-film method (the
>> only one that I should learned many years ago).
>> What about the ThinkTink supplies (resist and soldermask)?
>
> I don't have any experience with dry film, but I do have a metric buttload
> of the stuff.  In a fit of madness several months ago, I bought an
> unopened roll of AquaMer off Ebay.  I think my intention was to cut it
> into smaller portions and sell it that way.  Anyhow, I don't think I'll
> get to it any time soon, so if anyone wants it...

I found some info:

http://www.macdermid.com/electronics/pdf/AquaMer.pdf

What type of film is it?

Leon

A metric buttload versus an imperial buttload is ratiometric to the
respective base unit measures of weight.
Google's calculator tells me that 1 metric buttload is equal  to 0.984
imperial buttloads.

So, what is dry film and how do I use it?
--
Martin


Bob_xyz wrote:

>
> --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, David Griffith <dgriffi@...>
> wrote:
> >
> > On Thu, 25 Jan 2007, jcarlosmor wrote:
> >
>
> >
> > I don't have any experience with dry film, but I do have a metric
> > buttload
> > of the stuff. In a fit of madness several months ago, I bought an
> > unopened roll of AquaMer off Ebay. I think my intention was to
> > cut it
> > into smaller portions and sell it that way. Anyhow, I don't think
> > I'll
> > get to it any time soon, so if anyone wants it...
> >
>
> If you can break it up into reasonable sized chunks, you could
> probably sell it off right here in the group and at least break
> even.
>
> I'm not quite sure how much a 'metric buttload' is compared to
> an 'imperial buttload' but, unless the shipment came in a rail car,
> I'd think that this might be a good way to proceed.
>
> Regards, Bob
>
>

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

From: "Martin Klingensmith" <martin@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, January 25, 2007 2:04 PM
Subject: Re: [Homebrew_PCBs] Re: someone with dry film processing 
experience?


>A metric buttload versus an imperial buttload is ratiometric to the
> respective base unit measures of weight.
> Google's calculator tells me that 1 metric buttload is equal  to 0.984
> imperial buttloads.
>
> So, what is dry film and how do I use it?

It's usually applied with a laminator, I suppose the sort of laminator used 
for TT would work OK. Once it is applied it's used just like the 
presensitised boards that are available, provided it is positive working.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND transceiver
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller

I don't have experience with it either, but I'd sure like to try some.  
If you're going to distribute a bit, I'd appreciate a centibuttload or 
so to play with.

Norm
w6nim@...

David Griffith wrote:

> I don't have any experience with dry film, but I do have a metric buttload of the stuff.  In a fit of madness several months ago, I bought an unopened roll of AquaMer off Ebay.  I think my intention was to cut it into smaller portions and sell it that way.  Anyhow, I don't think I'll get to it any time soon, so if anyone wants it...
>
>
>

--- In Homebrew_PCBs@yahoogroups.com, "jcarlosmor" <jcarlosmor@...> wrote:
>
> Hi to everybody. I would like to start this thread to know/share 
> different experiencies about dry-film processing (home-made lamination, 
> imaging, developing, etc.)
> Right now I am planning to build a laminator, uv-exposure unit, 
> developing tanks, etc. (all of them DIY of course). After almost 15 
> years using all other methods of PCB fabrication, including silk-
> screening for whole big quantities of PCBs, I am tired of doing that 
> kind of stuff again and I am planning to use the dry-film method (the 
> only one that I should learned many years ago).
> What about the ThinkTink supplies (resist and soldermask)?
>



I may be able to help with dry film if anyone is interested. I ran a
commercial multilayer board shop for over twenty five years. Dry film
was the only resist we ever used. The earliest dry films were
processed with solvents and bad news to work with. We got into the
business right as solvent based films were being phased out.

We started out with semi-aqueous dry film which required a small
amount of butyl carbitol solvent to be added to the water based
developer. Butyl carbitol is a water soluble solvent and it helps to
remove the adhesion promoters left on the copper surface. When the
total aqueous films came on the market the solvents were no longer
needed. Now days all dry films are processed with weak sodium
carbonate (soda ash) solutions.

I use a DuPont HRL-24 laminator to apply the dry film. Developing is
done in a batch type spray tank similar to a spray etcher. After
etching the dry film is stripped in a weak sodium hydroxide(lye) solution.

When Kepro shut down their facility I purchased most of the larger
equipment they had for my own use. This included their CNC drilling
equipment and the entire silk screening department. Jim Keil who owned
Kepro is a personal friend of mine and he said I should offer the
photo resist coated materials for the small shops and hobby guy's that
use it. Thought about doing that many times but I don't know if there
is enough interest these days. Kepro couldn't do it any longer but
then again they had a large operation and the overhead that comes with
it. 

Using photoplotted or camera shot films and dry film photo resist will
produce the finest quality printed wiring with a minimal reject rate. 
The boards I use for my products are not very large and working alone
I can produce as many as one hundred pieces in an afternoon using
these methods with almost a 100% yield everytime. 

If there was enough interest I would offer these materials for sale.
Any comments or suggestions on this topic would be appreciated. 

Tom

Tom, I would like to know if what you have is positive resist or negative?
I  like the positive to work with in the home because of the pcb 
programs and
Ink jet printers. ( I use 2 prints stacked to get it black enough)
I used KPR resist for a number of years for all my hobbies, Ham Radio 
and R/C Airplanes.
I sprayed some and dip some and found the best for me was an old 78 rpm 
record player
and I just used an eye dropper to put some on the board in the center 
with it spinning
this gave me the best results with it.
regards
Robert Blumer
Billings MT


twb8899 wrote:

> --- In Homebrew_PCBs@yahoogroups.com, "jcarlosmor" <jcarlosmor@...> wrote:
>   
>> Hi to everybody. I would like to start this thread to know/share 
>> different experiencies about dry-film processing (home-made lamination, 
>> imaging, developing, etc.)
>> Right now I am planning to build a laminator, uv-exposure unit, 
>> developing tanks, etc. (all of them DIY of course). After almost 15 
>> years using all other methods of PCB fabrication, including silk-
>> screening for whole big quantities of PCBs, I am tired of doing that 
>> kind of stuff again and I am planning to use the dry-film method (the 
>> only one that I should learned many years ago).
>> What about the ThinkTink supplies (resist and soldermask)?
>>
>>     
>
>
>
> I may be able to help with dry film if anyone is interested. I ran a
> commercial multilayer board shop for over twenty five years. Dry film
> was the only resist we ever used. The earliest dry films were
> processed with solvents and bad news to work with. We got into the
> business right as solvent based films were being phased out.
>
> We started out with semi-aqueous dry film which required a small
> amount of butyl carbitol solvent to be added to the water based
> developer. Butyl carbitol is a water soluble solvent and it helps to
> remove the adhesion promoters left on the copper surface. When the
> total aqueous films came on the market the solvents were no longer
> needed. Now days all dry films are processed with weak sodium
> carbonate (soda ash) solutions.
>
> I use a DuPont HRL-24 laminator to apply the dry film. Developing is
> done in a batch type spray tank similar to a spray etcher. After
> etching the dry film is stripped in a weak sodium hydroxide(lye) solution.
>
> When Kepro shut down their facility I purchased most of the larger
> equipment they had for my own use. This included their CNC drilling
> equipment and the entire silk screening department. Jim Keil who owned
> Kepro is a personal friend of mine and he said I should offer the
> photo resist coated materials for the small shops and hobby guy's that
> use it. Thought about doing that many times but I don't know if there
> is enough interest these days. Kepro couldn't do it any longer but
> then again they had a large operation and the overhead that comes with
> it. 
>
> Using photoplotted or camera shot films and dry film photo resist will
> produce the finest quality printed wiring with a minimal reject rate. 
> The boards I use for my products are not very large and working alone
> I can produce as many as one hundred pieces in an afternoon using
> these methods with almost a 100% yield everytime. 
>
> If there was enough interest I would offer these materials for sale.
> Any comments or suggestions on this topic would be appreciated. 
>
> Tom
>
>
>
>
>
>
>
>
>
>
>
>
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> Yahoo! Groups Links
>
>
>
>
>
>
>

I've used some of the Kepro pcb materials in the past. I still have one of their hobbyist kits, but I expect it's exceeded it's shelf life. I wouldn't mind having some more of their presensitized PCB stock if it's available and reasonable.

Concerning the dry film processing, you mentioned stripping the material after etching. Isn't dry film also used for "solder mask" , in which case it remains on the PCB?

I'd expect that the etching of copper is completed, rinsed, then dry-film for solder mask is laminated on, then some type of light (UV?) exposure is performed through artwork for the solder mask, then the exposed portions of the mask are washed off. Perhaps this last "wash off" is actually called stripping?

I'd like to learn how to do solder mask and silk screens via dry film at home. Especially if it can be done little to no chemical solvents.

Paul

----- Original Message ----
From: twb8899 <twb8899@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, January 25, 2007 11:24:22 AM
Subject: [Homebrew_PCBs] Re: someone with dry film processing experience?









  


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

>

> Hi to everybody. I would like to start this thread to know/share 

> different experiencies about dry-film processing (home-made lamination, 

> imaging, developing, etc.)

> Right now I am planning to build a laminator, uv-exposure unit, 

> developing tanks, etc. (all of them DIY of course). After almost 15 

> years using all other methods of PCB fabrication, including silk-

> screening for whole big quantities of PCBs, I am tired of doing that 

> kind of stuff again and I am planning to use the dry-film method (the 

> only one that I should learned many years ago).

> What about the ThinkTink supplies (resist and soldermask)?

>



I may be able to help with dry film if anyone is interested. I ran a

commercial multilayer board shop for over twenty five years. Dry film

was the only resist we ever used. The earliest dry films were

processed with solvents and bad news to work with. We got into the

business right as solvent based films were being phased out.



We started out with semi-aqueous dry film which required a small

amount of butyl carbitol solvent to be added to the water based

developer. Butyl carbitol is a water soluble solvent and it helps to

remove the adhesion promoters left on the copper surface. When the

total aqueous films came on the market the solvents were no longer

needed. Now days all dry films are processed with weak sodium

carbonate (soda ash) solutions.



I use a DuPont HRL-24 laminator to apply the dry film. Developing is

done in a batch type spray tank similar to a spray etcher. After

etching the dry film is stripped in a weak sodium hydroxide(lye) solution.



When Kepro shut down their facility I purchased most of the larger

equipment they had for my own use. This included their CNC drilling

equipment and the entire silk screening department. Jim Keil who owned

Kepro is a personal friend of mine and he said I should offer the

photo resist coated materials for the small shops and hobby guy's that

use it. Thought about doing that many times but I don't know if there

is enough interest these days. Kepro couldn't do it any longer but

then again they had a large operation and the overhead that comes with

it. 



Using photoplotted or camera shot films and dry film photo resist will

produce the finest quality printed wiring with a minimal reject rate. 

The boards I use for my products are not very large and working alone

I can produce as many as one hundred pieces in an afternoon using

these methods with almost a 100% yield everytime. 



If there was enough interest I would offer these materials for sale.

Any comments or suggestions on this topic would be appreciated. 



Tom





    
  

    
    




<!--

--- In Homebrew_PCBs@yahoogroups.com, Robert Blumer <bob@...> wrote:
>
> Tom, I would like to know if what you have is positive resist or
negative?
> I  like the positive to work with in the home because of the pcb 
> programs and
> Ink jet printers. ( I use 2 prints stacked to get it black enough)
> I used KPR resist for a number of years for all my hobbies, Ham Radio 
> and R/C Airplanes.
> I sprayed some and dip some and found the best for me was an old 78 rpm 
> record player
> and I just used an eye dropper to put some on the board in the center 
> with it spinning
> this gave me the best results with it.
> regards
> Robert Blumer
> Billings MT
> 

Robert,  

All dry film photo resist is negative acting. It also require less UV
power to properly expose. I use film negatives that are photoplotted
to expose the dry film. My reject rate is almost zero with this
process. Photographic films will always give the best results.

I posted some information about a new liquid photoresist a few weeks
ago so maybe you should search for that information if you like the
liquid type of resist. It's water based, easy to use and is also 
negative acting.

Tom

Thanks for the information Tom, I will look back at the files and see if 
I can find the
liquid resist and check it out.
My UV source is from Think and Tinker,
(http://www.thinktink.com/stack/volumes/voliii/equipment/uvlamp/uvlamp.htm )
plans and have work very well for me.

Robert


twb8899 wrote:

> --- In Homebrew_PCBs@yahoogroups.com, Robert Blumer <bob@...> wrote:
>   
>> Tom, I would like to know if what you have is positive resist or
>>     
> negative?
>   
>> I  like the positive to work with in the home because of the pcb 
>> programs and
>> Ink jet printers. ( I use 2 prints stacked to get it black enough)
>> I used KPR resist for a number of years for all my hobbies, Ham Radio 
>> and R/C Airplanes.
>> I sprayed some and dip some and found the best for me was an old 78 rpm 
>> record player
>> and I just used an eye dropper to put some on the board in the center 
>> with it spinning
>> this gave me the best results with it.
>> regards
>> Robert Blumer
>> Billings MT
>>
>>     
>
> Robert,  
>
> All dry film photo resist is negative acting. It also require less UV
> power to properly expose. I use film negatives that are photoplotted
> to expose the dry film. My reject rate is almost zero with this
> process. Photographic films will always give the best results.
>
> I posted some information about a new liquid photoresist a few weeks
> ago so maybe you should search for that information if you like the
> liquid type of resist. It's water based, easy to use and is also 
> negative acting.
>
> Tom
>
>
>
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> Yahoo! Groups Links
>
>
>
>
>
>
>

Tom, what other facilities or machinery do you have for sale? I 
remember that Kepro had some interesting equipment (small in size) like 
a multilayer press, spindler etcher, etc.

> I posted some information about a new liquid photoresist a few weeks
> ago so maybe you should search for that information if you like the

BTW, did somebody contact Steve Johnson and find out who distributes this
product?

the guys listed on his page USE his products, but don't sell them...



 
____________________________________________________________________________________
Do you Yahoo!?
Everyone is raving about the all-new Yahoo! Mail beta.
http://new.mail.yahoo.com

He sells direct as well as through eBay.

John

  ----- Original Message ----- 
  From: Herbert E. Plett 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Saturday, January 27, 2007 1:51 AM
  Subject: Re: [Homebrew_PCBs] Re: someone with dry film processing experience?


  > I posted some information about a new liquid photoresist a few weeks
  > ago so maybe you should search for that information if you like the

  BTW, did somebody contact Steve Johnson and find out who distributes this
  product?

  the guys listed on his page USE his products, but don't sell them...

  __________________________________________________________
  Do you Yahoo!?
  Everyone is raving about the all-new Yahoo! Mail beta.
  http://new.mail.yahoo.com


   

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

>   > I posted some information about a new liquid photoresist a few weeks
>   > ago so maybe you should search for that information if you like the
> 
>   BTW, did somebody contact Steve Johnson and find out who distributes this
>   product?
> 
>   the guys listed on his page USE his products, but don't sell them...
> 

>> He sells direct as well as through eBay.
do you have any link?
on his site there is none (I found none)...

yes, on eBay it's:
http://stores.ebay.com/Advanced-Coatings-International
clumbsy transaction, no international support.



 
____________________________________________________________________________________
Bored stiff? Loosen up... 
Download and play hundreds of games for free on Yahoo! Games.
http://games.yahoo.com/games/front

--- In Homebrew_PCBs@yahoogroups.com, "jcarlosmor" <jcarlosmor@...> wrote:
>
> Tom, what other facilities or machinery do you have for sale? I 
> remember that Kepro had some interesting equipment (small in size) like 
> a multilayer press, spindler etcher, etc.
>

I bought some of the bigger plant equipment Kepro used to make the
products they sold. Also bought lots of large PVC plastic sheets they
used to make the etchers and other equipment. I was mainly interested
in the silk screening supplies and processing equipment. They said it
was all or none so I took it all. 

I didn't want the big horizontal process camera and tried to give it
away with no takers so I stripped off the good stuff and junked the
rest. In the old days those cameras were valuable. I used the vacuum
platten on the film end of the camera to make a small vacuum forming
machine. It works pretty good so not all was lost. 

Most of this equipment was bought for use in my shop to make my
products. I have considered making the spray etchers and spray
developers since all the equipment needed is here. I just don't know
how much of a demand there would be since they are expensive to make. 

There are some ways to make the Kepro style etcher cost effective. One
thing I've considered is to vacuum form the etching chamber which
would reduce the cost somewhat. We're kicking it around and may do it
but with a newer design and updated features. 

Even thought about making a "bare bones" spray etching chamber for the
DIY crowd. All the hard to fabricate parts would be included so it
would be kit style with an attractive selling price. Been kicking
these ideas around so any suggestions or comments would be appreciated.

Tom

--- In Homebrew_PCBs@yahoogroups.com, Paul Atkinson <pma32904@...> wrote:
>
> I've used some of the Kepro pcb materials in the past. I still have
one of their hobbyist kits, but I expect it's exceeded it's shelf
life. I wouldn't mind having some more of their presensitized PCB
stock if it's available and reasonable.
> 
> Concerning the dry film processing, you mentioned stripping the
material after etching. Isn't dry film also used for "solder mask" ,
in which case it remains on the PCB?
> 
> I'd expect that the etching of copper is completed, rinsed, then
dry-film for solder mask is laminated on, then some type of light
(UV?) exposure is performed through artwork for the solder mask, then
the exposed portions of the mask are washed off. Perhaps this last
"wash off" is actually called stripping?
> 
> I'd like to learn how to do solder mask and silk screens via dry
film at home. Especially if it can be done little to no chemical solvents.
> 
> Paul
> 


Paul,

Soldermask material is screen printed on the board after all the
etching and drilling is done. Curing of the soldermask coating is by 
heat or UV light depending on what masking material is used. In my
shop we use UV soldermask and screen printing inks. 

Most boards made today use photo imaged soldermask. The board is
coated with solder masking liquid, cured, UV exposed and the final
image is developed out in a spray tank. It's similar to processing dry
film etch resist. Primary etching resist would not hold up as a
soldermask because it gets brittle with age (like all of us... lol ).
It can't take the soldering temperatures either and would begin to
melt or delaminate.

Tom

Tom,

Thanks for the info.

Do you know if it is possible to do the liguid photo imaged soldermask on a hobbiest scale? Could it be developed without using a spray tank, or is the spray tank necessary to get the right reaction speed for exposed vs unexposed mask. (IE, so the unwanted area is totally stripped before the remaining area is adversely affected.)

Paul 

----- Original Message ----
From: twb8899 <twb8899@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Monday, January 29, 2007 1:07:50 AM
Subject: [Homebrew_PCBs] Re: someone with dry film processing experience?









  


    
            --- In Homebrew_PCBs@ yahoogroups. com, Paul Atkinson <pma32904@.. .> wrote:

>

> I've used some of the Kepro pcb materials in the past. I still have

one of their hobbyist kits, but I expect it's exceeded it's shelf

life. I wouldn't mind having some more of their presensitized PCB

stock if it's available and reasonable.

> 

> Concerning the dry film processing, you mentioned stripping the

material after etching. Isn't dry film also used for "solder mask" ,

in which case it remains on the PCB?

> 

> I'd expect that the etching of copper is completed, rinsed, then

dry-film for solder mask is laminated on, then some type of light

(UV?) exposure is performed through artwork for the solder mask, then

the exposed portions of the mask are washed off. Perhaps this last

"wash off" is actually called stripping?

> 

> I'd like to learn how to do solder mask and silk screens via dry

film at home. Especially if it can be done little to no chemical solvents.

> 

> Paul

> 



Paul,



Soldermask material is screen printed on the board after all the

etching and drilling is done. Curing of the soldermask coating is by 

heat or UV light depending on what masking material is used. In my

shop we use UV soldermask and screen printing inks. 



Most boards made today use photo imaged soldermask. The board is

coated with solder masking liquid, cured, UV exposed and the final

image is developed out in a spray tank. It's similar to processing dry

film etch resist. Primary etching resist would not hold up as a

soldermask because it gets brittle with age (like all of us... lol ).

It can't take the soldering temperatures either and would begin to

melt or delaminate.



Tom





    
  

    
    




<!--