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Does anyone know what might cause tiny pinholes in a lacquer finish? I've varnished most of my guitars but decided to try nitro on a couple. Before investing in spray equipment I thought i would experiment with some of the stew mac spray cans. After buffing out (waited over a month) the finish looked great, exept for hundreds of nearly miroscopic pin holes in the top which show up when viewed from certain angles. I tried cutting the finish on the top back with 800 paper and sprayed another coat, but they are still there. I guess they go all the way down to the Zinser Seal Coat I used as a sealer under the lacquer. Any ideas?

Thanks, Paul

That is called solvent popping. It is caused by the solvent not being able to escape the wet lacquer before the surface flashes off. Try spraying thinner coats.

Like Barry said, thinner coats and more time between coats.

_________________
I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Thanks for the help - Paul

Paul, I should have elaborated more earlier. Most manufacturers say you can re coat in an hour. 1 hour might be long enough if it's real hot, and real dry, but it's my experience that an hour just isn't long enough in the real world. Thicker coats cause the same problem for the same reason. As Barry said, the sovent has to evaporate, before the surface flashes. If the solvent is trapped before it completely evaporates it forms air bubbles under the surface. When you buff, there they are. I usually wait at least 3 hours between fairly thin coats.

_________________
I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

as noted, this is most likely solvent popping...

there is another possibility though...I've seen this happen before when a surface was not properly cleaned after sanding (i.e. there was a bit of residual sanding dust left) and then was sprayed over...

I've taken to removing the majority of dust, then wiping with mineral spirits and waiting 45 minutes for that to flash off, then using a wax free tack cloth just before spraying...

Man - I learn something new every day here - solvent popping! so that's what that is....
OK - thinner coats.