Crinkled spray paint over shellac....

[Harold Balzonia]

I want to paint some wood (don't judge...) with a very smooth gloss black finish as a base coat. The wood is bone dry. I sanded this piece to 220 and gave it two coats of shellac as a sealer. It dried for days. Then I sprayed on rust-o-leum gloss black enamel spray paint from a rattle can. This is the result:


IMG_0010.jpg

Obviously im using the wrong products or the wrong techniques or both. Can someone advise me how to get a smooth, gloss black finish on raw wood? (In this case it is alder if that makes a difference)

id be very grateful.... thanks!

[Art Mann]

Don't use shellac. It isn't thick enough to fill the wood pores and imperfections. Instead, use a high build primer made for the purpose.

[Wayne Lomman]

As Art says, use a high build primer, sand it smooth and then paint. I personally use 2 pack polyurethane for the top coat with a high build primer under it as recommended by the top coat manufacturer. It works without fail. Read the data sheet for each product so that you sand to the correct grade and observe the correct drying times. Cheers

[Frederick Skelly]

I don't mean to be contrary, but I do exactly what Harold did here and the Rustoleum lays down flat and smooth. Maybe I've just gotten lucky, but I've done it several times with nice results. I use a dewaxed shellac (Bullseye Sealcoat) and spray the paint on in light coats.

Fred

[glenn bradley]

Frederick is correct. Shellac is commonly used as a barrier coat between incompatible finishes and is included in many primers. Art is correct in that shellac is a sub-optimal filler and closely mimics the surface to which it is applied. If that rounded edge was super smooth with just the shellac and then wrinkled up, you have a chemical reaction. This begs the question as to what kind of shellac did you use? Rattle can shellac uses different carriers that something like Zinsser Seal Coat or shop mixed flakes. What was the shellac product used and if shop mixed, what was in it?

[Wayne Lomman]

Just looked at the picture on a decent sized screen. You do have an incompatibility reaction going on. In this situation, the problem is commonly caused by a soft coating under a harder coating, insufficiently cured enamel paint before application of the next coat, or over application of an oil based enamel. Everybody swears by shellac being a suitable primer. I don't. I know I say learn the rules before you break them, this is just one rule I never break anymore. However, in this case the primer is unlikely to be the problem.

If the Rustoleum you are using is a typical rattle can enamel, you have possibly either applied a second coat before the first coat was properly dry or you have applied a too thick coat. Oil based enamels can be a pain like this, especially the varieties commonly available at retail outlets. Industrial enamels are totally different and dead simple to use.

The solution is to strip it back, let it dry, re-sand, reseal with shellac and paint again using thin coats and allowing plenty of drying time between coats which is more or less what Fred Skelly does and it works. Cheers

[Harold Balzonia]

Thanks guys... the shellac undercoat was zinzer seal coat (dewaxed) and the paint was rattle can enamel from rust oleum.... I was pretty sure it was a chemical reaction as the shellacked finish was smooth as can be when I painted it. I suppose it's possible I used too thick of a coat(s) but I'm not usually heavy handed with the stuff. In fact, the other three colors I did the same way on the same stock of wood wound up perfect. Brown, Red and Blue all laid down flat, as expected.

It sounds like I might just need an even lighter touch with the gloss black. Thanks!

[Jim Becker]

You may also have had a "bad can" of the black paint...I've had some that didn't spray out cleanly myself...

[glenn bradley]

Thanks guys... the shellac undercoat was zinzer seal coat (dewaxed) and the paint was rattle can enamel from rustoleum....

Given this I would lean toward the top coat being the problem and not the undercoat. Sounds like you got it pegged.

[Thomas L Carpenter]

High build primer? How about some brand names. Thanks.

[Wayne Lomman]

Sorry, I'm on the wrong continent to recommend a brand. Do you have a decent sized auto accessories outlet handy? They should be able to help you. Just ask for a single pack sandable high build primer. Don't tell them it is for wood, they will go cross eyed and get confused with too much information. Cheers

[Art Mann]

I agree with Wayne, even if we are continents apart. You can get high build sandable automotive primer from Rustoleum and a whole bunch of other companies. The important thing is that it says "sandable". Latex primer isn't.