Often times people have problems with there photoresist stencil blowing off while sandblasting. This is a fairly common problem the arises. It doesn’t seem to happen as much with a regular vinyl stencil but does every once in awhile.
A fellow glass sandblaster, named John, emailed me about this problem and here is my response with a bullet list of rules and actions to consider.
- Use a Finer Abrasive Grit: There could be a few things to consider, but the one that comes to mind is that the grit being used is too large. I personally use about 150 or 180 grit. I probably wouldn’t use anything larger in size than 100 grit (but my grit standards are set at least 120 and finer). Sometimes they don’t emphasis this enough, but the finer the grit is, the less blow off problems you will usually have and the thinner the vinyl stencil can be. I talked about that in the ebook a little bit also. Alot of times, I will actually do some sandcarving with a 3 mil vinyl with a fine grit. Works fairly nice. By the way here is some more steps to follow for glass sandcarving.
- Ensure a Clean Surface: Another problem could be due to having a unclean surface. Even if the glass appears to look very clean, it still has oils and such from peoples hands. You can wipe the glass down with a cleaner such as rubbing alcohol.
- Dry Out the Resist, but not to Dry: A third, is to make sure that the photoresist is dry but not bone dry. I use the photoresist that doesn’t require an application of adhesive. Its most tacky when it is almost dry. If the photoresist still has moisture absorbed, then the photoresist won’t adhere very well.
- Lower the Air Pressure: A fourth rule, is to make sure the sandblasting pressure isn’t set at too high of a pressure. The photoresist company will usually have a recommended and maximum pressure that can be used for each specific photoreist thickness. Then it will also go back to the first rule I stated. If a larger grit is used, you may have to back off the pressure too.
[nonmember]Solutions to fix photo resist blowout problems. I talk about ensuring a clean surface, letting the resist dry enough, using the correct size grit, and the proper pressure setting.[/nonmember]