Homebrew PCBs

On 02/03/17 17:28, Larry Battraw lbattraw@... [Homebrew_PCBs] wrote:
>
...
> I've eventually come to the conclusion that the cheap and
> easily-obtainable negative brush-on photo-resist from China ($9
> including shipping to the US for 100g of concentrated resist that
> provides 300g when properly diluted, which is a ton of photoresist!) is
> the way to go.  I use an Epson inkjet with cheap and easy refillable
...

<http://www.ebay.com/itm/100g-Photoresist-Anti-etching-Blue-Paint-for-DIY-PCB-Photo-Etched-PE-NEW-/301857576850?hash=item46481d1792:g:Lt4AAOSwX~dWkyy~>

What do you use for the thinner?

I used all my commercial dry-film resist a couple of months ago.

It was atleast 10 years old, and i only stored it at room temperature in a dark 
case.

I got problems with the stuff not developing off easily, as if UV was getting 
through the black ink or something.

I found that by using 12g/Lt of Na2CO3 developer instead of 10g/Lt, all the 
problems went away and the unexposed resist would wash off easily.

I also found that just using a much lower concentration of NaOH stripper also 
works well as a developer.

I never had problems with the resist sticking because i used a decent megauk.com 
laminator that applies heat and pressure (i set it for 100degC).