How long after barrier coat of dewaxed shellac must you wait before lacquer coats?

[Mike Dowell]

I *should* know this being that I'm in the finishing business. Well, I have mixed luck dealing with fish-eye when refinishing furniture. So, because I don't really have time to bandaid problems as they pop up, whenever I do a table top, dresser top, or anything I think might have furniture polish/silicone contamination on it, I spray 1 or 2 coats of dewaxed shellac first. I've been in the habit of waiting 24 hours before spraying my lacquer coats on top of the shellac, and I'm wondering if that's overdoing it. How long do you wait before safely overcoating dewaxed shellac with Lacquer?

Also, and I've always wondered this but never had the guts to try it - regular non-dewaxed shellac. Like what you buy at the home store. Has anyone successfully used that as a silicone barrier coat, and applied lacquer on top of it? It's more convenient to buy that since home depot carries it. When I buy the gallons of "sealcoat" dewaxed shellac, I have to order online. Not that this is a big deal, but sometimes I'm in a pinch.

[John TenEyck]

Hmm, my local HD carries gallon cans of Sealcoat; surprised yours does not. But you can order 2, 1 gallon cans online from HD for about $75 with free in-store pickup. A real bargain if you use a lot.

I don't use NC lacquer, only WB topcoats. Anything after 1 hour drying of the Sealcoat is fine; never had any problems. I would think it would be the same for solvent based topcoats. More time doesn't hurt, just isn't necessary.

And I'd never use regular (wax containing) shellac if I was trying to seal in silicone. Sealcoat is cheap, works, and if I need to adjust the color I just add Transtint dye to it.

John

[Mike Dowell]

Hmm, my local HD carries gallon cans of Sealcoat; surprised yours does not. But you can order 2, 1 gallon cans online from HD for about $75 with free in-store pickup. A real bargain if you use a lot.

I don't use NC lacquer, only WB topcoats. Anything after 1 hour drying of the Sealcoat is fine; never had any problems. I would think it would be the same for solvent based topcoats. More time doesn't hurt, just isn't necessary.

And I'd never use regular (wax containing) shellac if I was trying to seal in silicone. Sealcoat is cheap, works, and if I need to adjust the color I just add Transtint dye to it.

John

Great feedback John, and thank you. Well, sometimes when I'm doing restoration work on something small, like a cocktail table, I might notice some fisheye. In the past, I would just hit it with a shot of spray shellac(dewaxed), but more times than not, it would turn oddly white. Not like blush. I hadn't thought it through enough, but I wonder if that was the solvents in the lacquer still evaporating, and doing so into the shellac. I'm worried about how long it takes for the shellac to completely evaporate the DA.

When you spray a seal coat, do you shoot right from the can, or do you dilute with DA? I'll have to check with my HD store, but I have never seen it there before.

Why only water based top coats? What do you prefer? (oh boy, now I'm getting side tracked)

[Jim Becker]

I've gone from water soluble dye, to oil, to de-waxed shellac to water borne top coat in a single day. The shellac can be re-coated relatively quickly...an hour or two at most, in my experience, especially for a sprayed barrier coat that's not overly thick. Alcohol flashes off fast...

As always, test it first...

And I also only use water borne top coats...I do not have nor to I intend to build a facility where I could spray solvent based lacquer, etc., safely.

[glenn bradley]

+1. Depending on the weather I wait 1 hour or so and move on.

[Mike Dowell]

OK, well it sounds like I've wasted a LOT of finishing time in the past! Hey, how thin do you all make your barrier coats? 50/50 (using the bullseye sealcoat)? Do you find one quick coat to be enough? I'm just always so worried about fisheye. It comes out of nowhere, and just as you've had 10 jobs with no problem, you relax your senses, and BOOM, there it is.

[Jim Becker]

I use Sealcoat right out of the can, sprayed. One coat is generally just fine as a barrier coat. Shellac is not meant to be "built" up like many other finishes. In fact, under water borne finishes, you can sometimes have issues if the shellac is "over built"...

[John TenEyck]

Same for me; one coat of Sealcoat sprayed straight from the can. I, too, only spray shellac and WB topcoats because my basement shop "spray booth" can't handle solvents safely. My favorite all around WB topcoat is GF's Enduro Clear Poly. Sprays like a dream and looks great. Truthfully, I haven't used a great number of products, mostly GF's products, but I am about to try TC's EM-9300 for an exterior door finish.

John