Homebrew PCBs

Hi,

I'm using an HP LaserJet 1300 set to "Dark" on 600dpi to print simple 
PCBs (10mil or greater widths).

When I look at the masked areas under a microscope after etching with 
sodium persulphate, I see a lot of porosity, i.e. little holes etched 
in the black areas. I'm ironing quite heavily and the boards look very 
solid when inspected under the uscope after the backing paper has been 
soaked off so I don't think that this is an adhesion issue....

Is there anything that can be done to make the ink less porous? I note 
that http://www.pulsarprofx.com/ have what they call a green "TRF" that 
is supposed to do this - anyone know what it really is?

Cheers

Nick

Hi Nick,
I haven't used the green TRF but I understand it works well. It
applies an additional coating that sticks to the toner and fills the
'little pinholes' I guess. I haven't had the pitting problem but I
still use Ferric Chloride. I tried the acid-peroxide once and although
it etched very quickly, I also had some pitting and undercutting that
I never see with the ferric chloride. Although the toner mostly holds
up, it doesn't seem 100% resistant to the very aggressive acids. My
guess is the acid-peroxide is better at etching through a very small
aperture like a pinhole and then it slowly eats the copper around the
edges of the toner. By doing so, it compromises the toner at the edge
and makes the hole a little bigger. This allows more etching, more
toner loss, ect, ect. What ever the case, I get the best board results
with the messy brown goo. I've grown fond of it myself. :-)

The other thing you might try is passing a heat gun over the board,
after removing all the paper, to seal the toner. I used to do this but
was finding it an unnecessary step.

- phil (KA0HBG)


--- In Homebrew_PCBs@...m, "Nick de Smith" <nick@...> wrote:
> 
> I'm using an HP LaserJet 1300 set to "Dark" on 600dpi to print
simple PCBs (10mil or greater widths).
> 
> When I look at the masked areas under a microscope after etching
with sodium persulphate, I see a lot of porosity, i.e. little holes
etched in the black areas. I'm ironing quite heavily and the boards
look very solid when inspected under the uscope after the backing
paper has been soaked off so I don't think that this is an adhesion
issue....
> 
> Is there anything that can be done to make the ink less porous? I
note that http://www.pulsarprofx.com/ have what they call a green
"TRF" that is supposed to do this - anyone know what it really is?

Hi,

 

This is my first post here so I hope this works J

 

I also use TT and I have the same problem. It isn't a big thing for me
because I also use UV technique for more complex or definite PCB's. 

But if there is someone out there that could solve this problem. I would
like to know about it.

I'm going to try "re"melting the toner by the use of a hot air gun.

 

I etch with Acid Cupric Chloride. A mix of HCl and H202 got me started. Now
only with air regeneration and HCl addition.

 

-Joe

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of pgdion1
Sent: Monday, 02 March, 2009 17:29
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: Porosity of laserjet ink...

 

Hi Nick,
I haven't used the green TRF but I understand it works well. It
applies an additional coating that sticks to the toner and fills the
'little pinholes' I guess. I haven't had the pitting problem but I
still use Ferric Chloride. I tried the acid-peroxide once and although
it etched very quickly, I also had some pitting and undercutting that
I never see with the ferric chloride. Although the toner mostly holds
up, it doesn't seem 100% resistant to the very aggressive acids. My
guess is the acid-peroxide is better at etching through a very small
aperture like a pinhole and then it slowly eats the copper around the
edges of the toner. By doing so, it compromises the toner at the edge
and makes the hole a little bigger. This allows more etching, more
toner loss, ect, ect. What ever the case, I get the best board results
with the messy brown goo. I've grown fond of it myself. :-)

The other thing you might try is passing a heat gun over the board,
after removing all the paper, to seal the toner. I used to do this but
was finding it an unnecessary step.

- phil (KA0HBG)

--- In Homebrew_PCBs@yahoogroups.com
<mailto:Homebrew_PCBs%40yahoogroups.com> , "Nick de Smith" <nick@...> wrote:
> 
> I'm using an HP LaserJet 1300 set to "Dark" on 600dpi to print
simple PCBs (10mil or greater widths).
> 
> When I look at the masked areas under a microscope after etching
with sodium persulphate, I see a lot of porosity, i.e. little holes
etched in the black areas. I'm ironing quite heavily and the boards
look very solid when inspected under the uscope after the backing
paper has been soaked off so I don't think that this is an adhesion
issue....
> 
> Is there anything that can be done to make the ink less porous? I
note that http://www.pulsarprofx.com/ have what they call a green
"TRF" that is supposed to do this - anyone know what it really is?





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

--- In Homebrew_PCBs@yahoogroups.com, "Nick de Smith" <nick@...> 
wrote:
>
> Hi,
> 
> I'm using an HP LaserJet 1300 set to "Dark" on 600dpi to print 
simple 
> PCBs (10mil or greater widths).
> 
> When I look at the masked areas under a microscope after etching 
with 
> sodium persulphate, I see a lot of porosity, i.e. little holes 
etched 
> in the black areas. I'm ironing quite heavily and the boards look 
very 
> solid when inspected under the uscope after the backing paper has 
been 
> soaked off so I don't think that this is an adhesion issue....
> 
> Is there anything that can be done to make the ink less porous? I 
note 
> that http://www.pulsarprofx.com/ have what they call a green "TRF" 
that 
> is supposed to do this - anyone know what it really is?
> 
> Cheers
> 
> Nick
>


Re-heat the PCB AFTER transfer to "re-flow" the toner and fill in the 
pinholes.

--
James.

--- In Homebrew_PCBs@yahoogroups.com, "James Newton" 
> Re-heat the PCB AFTER transfer to "re-flow" the toner and fill in 
the 
> pinholes.

What temperature does this stuff melt at?

I only ask ask we have a "range cooker" with a hot plate that runs 
about 250C - would that do? Not that SWMBO would be too pleased...

Nick

The "green film" is identical to the old laser foil. It is a mylar film with
a metalized fusible coating. Part of its success is just by remelting the
toner and pressing it down again
You can get the same effect by using the release sheet from laser labels by
Dennsion and re-ironing the pattern or running it though the laminator.

There are some craft hot air "embossing" tools that also work well.

Note, you do have to have good coverage of the copper by the toner. One of
my laser printers does a very poor job with large solid areas.

Myc

On Mon, Mar 2, 2009 at 1:20 PM, Nick de Smith <nick@...> wrote:

>   --- In Homebrew_PCBs@yahoogroups.com <Homebrew_PCBs%40yahoogroups.com>,
> "James Newton"
> > Re-heat the PCB AFTER transfer to "re-flow" the toner and fill in
> the
> > pinholes.
>
> What temperature does this stuff melt at?
>
> I only ask ask we have a "range cooker" with a hot plate that runs
> about 250C - would that do? Not that SWMBO would be too pleased...
>
> Nick
>
>  
>


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

--- In Homebrew_PCBs@yahoogroups.com, "Nick de Smith" <nick@...> wrote:
>
> What temperature does this stuff melt at?
> 
> I only ask ask we have a "range cooker" with a hot plate that runs 
> about 250C - would that do? Not that SWMBO would be too pleased...
> 
> Nick
>

Toner melts at different temperatures depending on the type of the 
printer. Most melt around 300'F so your 250'C hot plate should do the 
trick, if only when SWMBO is otherwise occupied ;o)

See 
http://techref.massmind.org/techref/tonertransfer.htm for more 
information.

--
James.