Homebrew PCBs

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?





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