Alder Body // color coat is cracking

[RPM]

Hi All, I have an alder body here. The gray automotive primer I used started spitting globs. So, I sanded it back and switched to ColorTone white vinyl sealer. This also spit a few globs. I did warm the cans well in warm water. So, I sanded it back a bit and switched to Zinnser Bullseye aerosol shellac. Everything looked sealed and scuff sanded and wiped clean. Next, I sprayed ColorTone vintage white lacquer. This finish cracked within the hour of drying. I sanded it a bit, and applied a second coat of vintage white lacquer. There was less cracking, but still some. So, is it advisable to press on and scuff sand between coats until I arrive at a smooth finish, or sand back to pure wood and start over? I think the vintage white lacquer shrank because it was sprayed over the Bullseye shellac.

I think there's just too much cracking. I'll have to sand back to wood. The ColorTone vintage white lacquer may be applied to bare wood. That's what I should have done in the first place.

 

[Spud]

Were both the primer and shellac dry and sand-able?

 

[RPM]

Yes. The humidity here today was about 20% which is unusually low. Maybe the vintage white lacquer just dried too fast.

 

[stratamania]

It is also possible that at least one of these products is incompatible with the others.

As it is, it looks quite artistic, but probably not what you were going for. So I would advise sanding it back and using products that are known to work together (such as from the same brand), following an advised finishing schedule.

 

[teleme01]

i think it looks kinda cool, i wonder what it would look like with colored grain filler

 

[Rick]

I'm thinking leave it, and fill with a clear filler, or maybe black, then clear coat. Or sand back to bare wood, and find the Aaron's rattle can finish and follow the directions and the products he uses. Me, I'd go for the cracked look and have a unique guitar. Celebrate it!

 

[DuckBaloo]

So, is it advisable to press on and scuff sand between coats until I arrive at a smooth finish, or sand back to pure wood and start over?

You would have to sand back to wood. You cannot just over-spray that without expecting problems later. (I do agree with @Rick that, if you liked the look, it might be possible to stabilize as is).

I'm not sure what the issue is, de-waxed shellac is pretty much the Rosetta stone of finishes, it sticks to everything and everything sticks to it. Cracks like that are usually what you see when the wood, or prior finish, expands/contracts due to temperature change, breaking the upper coat.

I have to suspect the very low humidity.

 

[NedRyerson]

Also, what was the temp in the shop when you sprayed?

 

[RPM]

Temperature was about 65F. I thought the non-wax shellac would be fine too. I'm sanding back to bare wood. Start fresh. And then test spray as I go, like I should have done the first time.

 

[Dave B]

Call it a "relic" and sell it for 600% more than it's worth. Then buy a new body and start over.