Clear lacquer turning white-ish

[cog]

Question: I made a wooden gearshift knob, lacquered it with a car clear aerosol gloss lacquer - multiple layers - but it is getting whitish now - most likely humidity - what can I do about that? Should I use a two component paint, or can it be the wood?

[Bob Cleek]

No idea for sure why the rattle can gloss lacquer clouded on you. The defect you describe is usually related to high humidity in the environment when the lacquer is applied. Alternately, the moisture content of the wood itself may be an issue. Wood readily absorbs moisture and automotive clear lacquer is designed to be applied to metal, not wood.

 

If I were you (and I admit I'm not,) I'd strip it to bare wood. Sand perfectly smooth. Apply a sealer coat of thinned spar varnish to soak into the wood and then eight coats of spar varnish, sanding lightly between each coat to key the surface (don't sand off the previous coats. The object is to build up a thick coating that provides some depth to the varnish that enhances the wood grain. (Use a tack rag to remove all traces of dust before varnishing.) If you really want to get fancy, after the eight coats of spar varnish dry well, hand rub the knob (or machine polish it if you have a wheel) with rottenstone and pumice until you obtain the level of gloss you desire. (Obtainable at any paint store. Follow simple instructions on the container.) This will provide a deep fine-furniture finish that won't look garish like high-gloss varnish alone can often look and its incredible smoothness with be a pleasure every time you touch it. (This is how Rolls Royce finished the interior trim on their now-classic motorcars. Modernly, Rolls Royce coats the wood trim with a number of proprietary resin coats that are then baked to cure the resin, after which they polish the surfaces with fine abrasives like pumice and rottenstone in the old fashioned manner.)

 

 

Edited February 24, 2023 by Bob Cleek

[cog]

Thank you, Bob. I'll have some shopping to do.

[Joseph Schmidt]

On 2/24/2023 at 3:01 AM, cog said:

Question: I made a wooden gearshift knob, lacquered it with a car clear aerosol gloss lacquer - multiple layers - but it is getting whitish now - most likely humidity - what can I do about that? Should I use a two component paint, or can it be the wood?

As a wood furniture maker, I've sprayed many hundreds of gallons of Nitrocellulose Lacquer. Sometimes, seemingly for no reason, that whitishness appears. It is frequently moisture related, as lacquer dries very quickly and gets cold in the process, drawing moisture from the air. A quick fix, that nearly always works, is to spray pure lacquer thinner on the project, just enough to wet the surface, allowing the trapped moisture to escape. Sometimes that needs to be done more than once. It has saved many thousand dollar custom executive office furniture pieces for me.. Worth a try.

[cog]

Thank you Joseph. In this case the lacquer was already dry for several months, but certainly worth while remembering!