Wb Shellac Vs Sealcoat

[David Scigliano]

I would like to convert to all wb products, but have not tried wb shellac yet. I see that Target coatings sells wb shellac and was wondering if anyone has tried it? I will mainly be using this as a barrier coat between wb dye and wb toners or laquers. I like sealcoat but dont like the clean up or unable to spray in garage.

[Doug Shepard]

Just my $0.02 - I think you might risk some color bleed leaching back out of the wood over the WB dye. You'd be using the same 'solvent' and might cause some of the dye to re-dissolve and get smeared or blotchy. I'd be interested myself whether this is/isnt a problem though.

[Steve Schoene]

Haven't used it myself, but feedback I've heard is sort of OK but...

In particular using it as a barrier coat over waterbased dye doesn't strike me as a good idea. It would have the same problem of picking up dye as other waterborne finishes would. I know spray is generally the faster way to go, but with one coat of alcohol dissolved shellac, brushing it on should be pretty quick and not generate a lot of problems, and add zilch for clean up since you don't even have to clean the brush. (It resoftens in the next batch of shellac.) And while flammability concerns do exist for shellac, the mostly ethanol alcohol solvent isn't generally considered to be as noxious as petroleum based solvents.

[Howard Acheson]

Keep in mind that waterborne "shellac" is nothing like standard shellac. It is basically a waterborne acrylic with a very small dollop of shellac added so the marketing department can call it "shellac". It is not water and vapor impervious, does not work as a barrier coat and it does not create the same type of appearence as standard shellac. Like other waterborne finishes it about equal to lacquer in durability.

It is always risky to apply a waterborne finish over a water based stain. The water in a waterborne finish will tend to dissolve the coloring dye. Think of what happens to a watercolor painted picture when it gets wet. Same thing happens when water gets onto waterbased dyes. That's the reason finishers will apply a barrier coat of real shellac over a waterbased dye if they plan to use a waterborne clear coat.

Many waterborne acrylics are fine finishes in their own right. It's unfortunate that their manufacturers frequently see fit to apply common finish names to them. It's done to give a familier name to a product in the hopes that the prospective finisher thinks it is something familier. At least Minwax is most honest in using "Polycrylic" as their name for their waterborne acrilic finish. It's not waterborne varnish and they don't call it that. Now, if we could get them to stop calling their linseed oil/varnish product "Tung Oil Finish".

[Steve Schoene]

I don't think the WB shellac is mostly acrylic. What I understood is that it is shellac modified with an alkali making it water soluable--rather like shellac used in hats. (The MSDS shows up to 30% modified shellac resin, a few percent of gycol ethers in different forms, and a minimum of 66% water. Target's MSDSs show the acyrlic in its other coatings so I don't think the omission is an artifact of loopholes in the MSDS requirements.)