Poly over lacquer

[Busdriver]

Can I put poly over lacquer? I posted a couple of months ago about my cherry cabinets. The lacquer is coming off.

Instead of relacquering, I thought about putting poly over them. If I can't do this, what other topcoat can I put over the lacquered kitchen cabinets?

Thanks
Eddie

[Stwood_]

No. Poly will eat the lacquer off, making a big mess. Best to remove and resand.

[jteneyck]

I agree.  If the lacquer is coming off it's telling you there's a problem that needs to be dealt with.  Putting something over it might kick the can down the road for awhile, but then you'll have a bigger mess to deal with.  I would strip it off and start over.   And don't use NC lacquer on kitchen cabinets.  Not durable enough.  Use something that's KCMA rated.  Plenty of good products to choose from, both solvent and waterborne.  Pick a product line and use their recommended dye, stain, sealer, and topcoat system.  That's the best way to avoid compatibility problems.  

John

[fredhargis]

I don't disagree with anything said above. I went back and looked at your original post, I'm guessing that was NC lacquer you used originally (?). If true I'm not sure where you got the advice, but it's just not a good choice for kitchen cabinets. Often when you see someone recommend lacquer for that application, they are referring to catalyzed or even a waterborne "lacquer". In the finishing world the names of finishes is so screwed up it pays to ask someone to be more specific. You said you want to top coat with "poly"; that in itself could be a few different things though most commonly it refers to an oil based varnish. But there are also waterborne finishes that some call "poly", and there's probably other stuff with the name as well. But given the high possibility that you used NC lacquer, your best coarse of action would be a complete strip (I know, uggggh!) and start from scratch. If the lacquer is failing it will continue to do so, and taking whatever is on top of it with it. The recommendation to use a KCMA approved finish is good, then you know you got it right.

[Cooler]

Lacquers (water based or otherwise) are chosen by manufacturers for the fast dry times, and not the durability.  Almost any oil based poly and most water based poly finishes that are brushed or sprayed will outperform lacquers from my experience.  

But as a manufacturer, especially of kitchen cabinets which take up a lot of space, it is important that you can box them up right away and ship them out.  You can't box up poly finished products right away.  Even after 12 hours corrugated pressed against the finish could adhere.  

So don't go thinking that the commercial finishes are superior to the brush or spray on finishes that are generally available.

If adhesion is a worry, I would apply a coat of Sealcoat and then your topcoat.  The shellac seems to stick to almost everything and almost every finish seems to stick to the shellac.  It makes a good base coat.