Lacquer “waxing”
I’m using Miniwax lacquer for the first time and it’s not working out very well – the third coat is waxing white. I noticed a gummy builld up about 5 minutes into applying this last coat.
The piece is a cherry bowl (solid, only air dried for 2 weeks), roughly 8×8″. First coat was Minimax Sanding Sealer, then two coats of lacquer (each lightly sanded after one day of drying), all applied with a natural bristle brush. Third coat started out ok but started to get gummy/waxy build up on brush. I thinned the brush out with lacquer thinner and let it sit for two hours. About half the surface has a white, waxy build up on it now. Look like it got hit by flock of pidgeons. Room temperature was about 58 last night (62 when I applied the third coat). It looks like it will buff out but I don’t know what I did wrong: wet wood, too cool ???
Tom
Replies
Sanding sealer is a possible culpret, especially with wet wood. The chemical soap, stearate, that it contains makes it quite a bit less moisture resistant that lacquer by itself. It may well have reacted with moisture in the wood. Finishing wood while still green presents hazards in general.
Sanding sealer is not needed or desirable, except in a few high tech finishes where a particular sealer (not your run of the mill stearated sanding sealer) is mandated by the manufacturer. Otherwise it just reduces the strength of the finish. It is marketed only because it induces people to buy another can of product. It's use in industrial settings is just an expedient to reduce the finishing time a bit, where time is money.
The good news is...
Tom,
As long as the minwax products are not catalyzed, the good news is you may be able to remove the entire finish easily with pure lacquer thinner - and redo as Steve has mentioned. (Test on perhaps the bottom first).
I use the Deft lacquer - as when I compared to Minwax MSDS - the Deft seemed closer to a traditional nitrocellulose lacquer. Deft is absolutely removeable with lacquer thinner.
I also find it difficult to apply more than one brush coat. When I tried multiple brush coats, I ended up with a heavily brush-marked mess. I now do all subsequent coats by spraying.
Remember, with evaporative lacquer like Deft, you do not need to bother sanding between coats. The subsequent coats dissolve into the earlier.
If you do get brushmarks or orangepeel, you might want to try the 'pullover' technique that can easily be used with Deft. Its similar to shellac French Polishing - but without any grits. It just uses a 'pullover rubber' (pad) with a solution of approximately 1/3 lacquer thinner and 2/3 denatured alcohol (ethanol - ethyl alcohol). Search 'pullover' on Knots for more info. FWW on-line 'members' can also see a video on it by Sean Clarke.
Lacquer 'Pullover' works great, and is easy to do once you get the hang of it.
Good Luck!
Chris
Pullover Technique
Chris
Thanks for the advice. I'm going to give it a try. I'll post the results as soon as I have some.
Tom
Pullover Technique II
Chris,
I tried the "pullover" technique. It did improve the mess but I was not going to get acceptable results without at least another hour of rubbing. Instead I remounted the bowl on the lathe and sanded till I was satisfied (about 15 minutes). I'm spraying diluted lacquer now (same minwax with 50% lacquer thinner). After three coats the bowl looks pretty good but I think I could reduce the thinner (to a 3 lacquer:1 thiner) and still get good results. Is there a recommened thin ratio ?
Tom
This forum post is now archived. Commenting has been disabled