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Subject: Re: [Homebrew_PCBs] Re: laser ablation of paint on copper clad

From: Slavko Kocjancic <eslavko@...>
Date: 2014-12-10

On 10. 12. 2014 17:52, 'Jeff Heiss' jeff.heiss@... [Homebrew_PCBs] wrote:

What solder resist do you use?  Are you using photoresist as solder resist?

 

Jeff

 

I use locally produced photoresist (liquid) and striped out after etching by scrubbing.
For now I just apply rosin (colophony) dissolved in isopropil alcohol as it helps with soldering too and 10 years old boards seems like new.
But I do some tests with UV curable solder mask from ebay
http://www.ebay.ie/itm/180917181008?ru=http%3A%2F%2Fwww.ebay.ie%2Fsch%2Fi.html%3F_from%3DR40%26_sacat%3D0%26_nkw%3D180917181008%26_rdc%3D1

and works nice but need at least 10x more laser power to cure.
I tested to slow down motion 10 times but got some strange bubles in paint. Probably related with nitrogen exhaust from paint itself. But if I do it fast and do 10x repeat then harden as should. (I scan same line 10 times and after that advance to next line)
For now with laser I have is just inpractical as it take to long time.

Slavko.