Bubbles in my spray

[Arron]

I sprayed some red cedar today with lacquer. I sanded it, then brushed the dust off, then blew the dust off with a air gun on the compressor, washed it with a turpsy rag, then left it in the shade to dry. Then I sprayed it (outside), moving it aside to dry in the sun. Looking at it later, there are dozens of tiny air bubbles.

Normally, I would use a timber sealer under the lacquer (ie Wattyl Rediseal under Wattyl Stylwood) but I put the lacquer directly on the raw wood today because I didnt want the sealer to dull the look. Nonetheless, I suspect I would have still got the air bubbles with the sealer, though they would be easier to deal with as the sealer is so easy-sanding.

The bubbles appear to be aligned along the deepest pores in the grain, so I"m thinking its the expanding air coming out of the grain ? What did I do wrong ? Is there any way to avoid this ?

cheers
Arron

[soundman]

Air comming out of the grain is exactly what you have.

some timbers are realy bad...plywood is a shocker.

This is why we use sanding sealers.

If you are using the right sealer it will not dull the finish actally on the contrary.

with open grain woods you WILL have this problem, we need to choke out the grain first will sealers...remember most of it, you will sand off leaving only what is filling the holes where the air is comming from.

It can be a real PITA.....you think you have got it choked then you lay up a coat too heavy, the underlying coats disolve and more air comes up.

remember for the air to come up the finish has to go down.

the probem with spraying is that it does not grind the product into the fracks and fisures...I've taken to brushing or rubbing at least the first coat of sealers & undercoats on wood.

what is common is when you are spraying....if bubbles are seen, rubbing the area with ya finder and giving it another slash...if it does not fix and flow out...ya gona be sanding again anyway.

cheers

[Arron]

Thanks for the detailed reply Soundman. I take it you are saying that the only real way to deal with this is to prevent it happening by closing off the pores first.



the probem with spraying is that it does not grind the product into the fracks and fisures...I've taken to brushing or rubbing at least the first coat of sealers & undercoats on wood.


Interesting statement. I've wondered about this. What do you rub on under spray lacquer ?

cheers and thanks
Arron

[soundman]

Well that is another question.

Laquer (more of the same), the related sanding sealer ( easier to sand that top coat laquer), shelac, various grain fillers both off the shelf or made up.

cheers