Failed lacquer finish

[mike wacker]

I built this really cute little table and chair set for my 1.5 year old Granddaughter for this last Christmas. When she saw it under the tree pretty much everything else got ignored. Giant happy dance by Grampy. Then comes the epic fail. After about a week the table top looked awful and the tops of the backs had "finger prints" in the finish.

I made the whole thing out of Baltic Birch and finished it with multiple coats (6 or 7) of rattle can lacquer (no stain) in my "heated" garage. About 60 degrees F. Waited the twenty minutes between coats the directions implied and the prior coats all felt "dry" not tacky at all. It was a last minute project of course but the table and chairs had 24 hours in the house before the little one got to it. My plan is to wait for warmer weather, sand it all down and start again.

Three questions: I'm guessing the lacquer needed more time to cure. Does that seem likely cause? Secondly is lacquer just not durable enough? And lastly should I go with a poly finish instead after I sand it all down?

[Ken Fitzgerald]

Mike,

I could be wrong but....I would suggest reading the manufacturer's application recommendations. I don't know what brand you used but Minwax recommends 77º F temperatures and 50% humidity for application of their rattle can lacquer. They also recommend 30 minutes drying time between coats. They also state any variations from these recommendations could lead to longer curing times.

I agree with your assumption that the lacquer needed to cure longer.

Lacquer is used regularly on furniture. I have a neighbor who's a professional painter/finisher. He uses catalyzed lacquer all the time as a spray finish on cabinets but I doubt it is the same as rattle can lacquer. In my opinion, lacquer is not as durable as polyurethane but I'd think it would be durable enough for children's furniture.

[Andy Giddings]

Agree with Ken on probable cause. Of course if you use a water based poly you can bring the work inside in the warm after the existing finish has been removed, finish it earlier and do another happy dance :-). Done this plenty of times when its too cold in the garage

[Art Mann]

I spray a lot of rattle can Minwax lacquer on plaques, signs and small gift items I sell. I have had really good success with it. I have found that I can get away with spraying and curing it in a 70 degree shop but that is the absolute minimum I will use. It seems not to cure very well if it is much colder than that no matter how long you leave it.

For high durability applications, I only use spray polyurethane.

[mike wacker]

10/4 as I suspected. but..... can I sand the lacquer down till I remove the damage with out going down to the thim laminate layer and poly over it? Will poly "stick" to the remaning lacquer?

Thanks again

[Bill Adamsen]

I have been successful "polishing" the MW Rattle can spray lacquer when cured as shown in the attached. So that might be a way to salvage or restore the finish and come out a winner with minimal effort. I use the Festool polishing pads and compound on a standard 3mm orbit ROS at low speed.

edit - it may or may not be relevant to your project, that finish has stain underneath and there were no issues with rub through. Client did not like the glossy satin finish, and we went another route.

[Mike Dowell]

10/4 as I suspected. but..... can I sand the lacquer down till I remove the damage with out going down to the thim laminate layer and poly over it? Will poly "stick" to the remaning lacquer?

Thanks againMike, as long as you scuff the existing finish with, say 320 or so sand paper, the poly will mechanically adhere. The problem is not so much the adherence, but the fact that different finishes expand and contract at different rates. This problem is exacerbated when you connect two thick coats of finish together. I would suggest you let it sit a couple weeks(from the last coat of lacquer), then sand it down a bit with 320, then if you want to use poly, just wipe on 1 coat - done. I'd recommend using wipe-on poly, or make your own 1:1 poly/mineral spirits. Good luck!

[John Sanford]

You COULD strip it off and redo it, but I wouldn't, unless you want the performance characteristics that a different finish (poly, acrylic, shellac) can give you. It's lacquer, which means that you when it's warm enough, you can scuff sand it to get the fingerprints, which should have cured by then, and just hit it with another coat. Each coat of lacquer will partially dissolve what's already there and merge. It's not a "film finish" in the sense that varnishes are, where each coat is a distinct layer. Lacquer and shellac both form a single layer which just gets thicker and thicker. This is what makes both so easy to repair.

[mike wacker]

Thanks to all. Guess I have to wait for some 70+ temps