shellac help needed

[Nick Crivello]

Hi guys,

Table project I'm having trouble with. Two questions really.

1.) I'm using a dewaxed garnet shellac that I mixed with Mohawk shellac reducer following the 2lb instructions. Is it normal to have a large clump of sludge in the bottom of the mason jar? The smaller test batch I made didn't do this.

2.) Blushing/sanding off shellac difficulties. I'm making an oval coffee table top out of cherry. Using a dewaxed garnet shellac to help color balance the boards and give it a warm tone; I'm sanding the raw wood up to 220 then applying coat of shellac. Lightly sanding then spraying with GF high performance. I'm running into blushing/cloudiness on the edges/end grain. When I go to sand it back, and sanding the poly, the shellac is removed, leaving sections of raw color vs the warmer tones. It's primarily on the edges and the bevel on the bottom side of the table. The transitions to the bevel are prone to the shellac coming off; would easing the edges help?

I was using a damp towel to wipe dust off between the coats, I think the moisture is causing the blushing(?). I will use compressed air and dust extractor instead to avoid this.

Should I apply 2-3 coats of shellac to prevent it from coming off so easily?

[Jim Becker]

1) any undissolved shellac flake material should be strained out by decanting into another container with a filter cone

2) be sure that the shellac has fully evaporated all the alcohol/reducer before you top coat with something else. Don't "sand" the shellac. Use a simple white pad to knock off any fuzz, clean it off with a dry lint free towel/rag (no water needed) and start shooting your waterborne top coat. Do not sand the GF HP until you have two or three light coats on it and your sanding should be limited to only what's necessary to remove nibs, etc. If you have to do excessive leveling, you need to consider your spray setup and technique. I use the white pad first. If that doesn't do it, I'll swipe it lightly with 400 wet and dry by hand. If it needs more than that...something is amiss

[Nick Crivello]

1) any undissolved shellac flake material should be strained out by decanting into another container with a filter cone

2) be sure that the shellac has fully evaporated all the alcohol/reducer before you top coat with something else. Don't "sand" the shellac. Use a simple white pad to knock off any fuzz, clean it off with a dry lint free towel/rag (no water needed) and start shooting your waterborne top coat. Do not sand the GF HP until you have two or three light coats on it and your sanding should be limited to only what's necessary to remove nibs, etc. If you have to do excessive leveling, you need to consider your spray setup and technique. I use the white pad first. If that doesn't do it, I'll swipe it lightly with 400 wet and dry by hand. If it needs more than that...something is amiss

Thanks Jim,

Everything you say makes sense. I like the idea of getting a few coats of poly on first; it essentially gets a build up over the shellac. I've been using the maroon, grey, and white scotchbrite pads. The GF HP is going down really well; was just following the instructions.

[Jim Becker]

You have to consider that you are spraying on your finish and therefore, the actual coats are not very thick especially after curing overnight. It can be very dangerous to abrade them before you get a few coats on and let that all settle out because unlike brushed oil based products, you can cut through them by even looking at them too sharply. Knocking off any nibs/fuzz is kewel and doesn't take much to do. Your subsequent coats will fill in around and over those areas and they will disappear. I strive to try and get the best overall finish "off the gun" and avoid any sanding I can. The exception to the latter is that for guitar bodies, I will do a final level with 800 wet and dry (used wet) and then work up through MicroMesh to 12000 and then buff. I don't do that with furniture...it's WAY too much work!

[Mel Fulks]

I would take out the clumps and hammer into mush , then throw ‘em in GOOD denatured alcohol. Just leaving the top off for a while
turns denatured alcohol into alcohol mixed with water. When buying DA check the can tops , some are usually loose.

[Paul F Franklin]

Jim's advice is right on as usual, I'll add a couple of points:

If you're not grinding the shellac flakes before mixing with the solvent, that both speeds up the dissolving process and minimizes the clumping issue. I just use a cheap spice grinder. But you should still strain as Jim said. Multiple coats of shellac doesn't hurt, but you may want to use blonde or super blonde for the additional coats to avoid getting darker than you want.

If your work area is cool/cold, that lengthens the time you have to wait for the shellac to fully dry/cure/set.


*slightly* easing sharp edges helps any finish bond better. And when using a toner like garnet shellac, it helps minimize a lighter line right at the edge caused by the finish being thinner there. Just a quick swipe or two with 220 grit on a sanding block is good enough; you don't want to round them over, just knock off the sharpest bit of the edge.

If you use compressed air to dust off the finish, make sure there's no oil in it, or water for that matter. Probably safest to just avoid the compressed air. I use a lint free cloth moistened with DA to wipe the work off before (not after) applying shellac.

[Mel Fulks]

I see the main reason for straining shellac is bug parts. Shellac is made by bugs !

[Nick Crivello]

Thanks you guys.

I’m going to sand everything down to 120 and start fresh.

Running short of the GF HP; local shop was out but did have GF enduro clear. Will give that a shot this time around.

[Jim Becker]

I see the main reason for straining shellac is bug parts. Shellac is made by bugs !

That is fortunately (!) not an issue in most shellac that folks buy today in flake form, especially for wax free products. But straining out any "stuff" that accidentally gets in it while mixing or any undisolved flake is just a good practice.

[Mel Fulks]

It’s been perhaps 20 years since I needed shellac , but I used the flakes and there were some bug pieces in it. I read the book
“Shellac and its Uses” …or close to that, and that is where I read the bug thing ….and I did strain out some bug limbs. It’s a simple
process thanks to women’s thinner clothing.

[Jim Becker]

Mel, there are some grades of shellac that do often have "bug parts" in them, they tend to be dark and are often referred to as SeedLac because they are less refined. Folks who use them do so for specific reasons. The more refined products (both waxy and de-waxed) are not as likely to have this "feature" because of how they are refined/processed to get the color and other properties like being wax free. And yea, "back in the day", old nylon stockings were a staple for straining things. In "modernity" we can simply buy disposable filter cones.