Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

On Mon, Oct 13, 2014 at 4:04 AM, alan00463@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:

 

Suspecting nail polish might come in green, in blue, and in purple, I googled "nail polish as solder mask".    I found one bloke who  claimed to have used enamel nail polish as a homebrew PCB solder mask.    He said to use enamel, but not acrylic.

 Nail polish doesn't sound particularly likely. 

Here's the 3 best ways for soldermask at home in no particular order...

1.  Vitrea 160 paint from a good art supply store (important, specifically Vitrea 160, other similar products do not work).  Use toner transfer to mask off the pads, spray a slightly thinned vitrea 160 (I thin with meths, but this probably makes the toner-cleanup more difficult at the end,water might be better, but it's trickier to spray).  Allow to dry (don't worry about waiting 24 hours, just until it's touch dry).  Bake for about 45 minutes, at 180 degrees C (well, 180 on my oven, your milage may vary).  Use acetone and a bit of elbow grease to remove the toner.  The vitrea is very strong, electrically insulating, and heat resistant, solder doesn't stick really to it as long as there is flux.  Advantage: cheap and readily available from art shops in a wide selection of colours.  Disadvantage: you need to spray it (airbrush) it on, and do toner transfer to mask the pads, and it's not always easy to clean off the toner.

2. Dry Film Soldermask (Dynamask).  As discussed already in this thread.  Advantage: easy to apply.  Disadvantage: expensive and hard to get.  Alternative - use dry film resist instead, bake it to further harden, not that strong to abrasion, but easy and cheap to obtain, electrically insulative.

3. Liquid Photoimagable Soldermask (UV cure paint/ink) from ebay etc.  There have been previous discussions about this, a fellow Kiwi has done some further experimentation, in summary: sprat it on, he uses a 0.8mm gravity gun, thinned with acetone just enough to spray it, dry at 105 degrees C for 30-5minutes (temperature is fairly critical), the paint doesn't really "dry", more develops a "skin", align artwork carefully and expose (quite a long exposure, 15 minutes with 30w of uv bulbs), wipe off the uncured paint with acetone (I woudl follow that up with exposing without mask for another period of time to fully cure).  Advantage: cheap and easy to get from eBay.  Disadvantage: it takes a lot of practice.

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