I often heed Mike Pekovich’s advice to use a wash coat of shellac before assembly to make cleaning up any glue squeeze-out an easier process. Like Mike, I use Zinsser Seal Coat cut 50% with denatured alcohol.
For reasons I cannot fathom, Seal Coat is becoming difficult to find in my area (west coast of Florida, not Mars). The big box stores, hardware stores and even Woodcraft, only seem to have Seal Coat by the gallon, if they carry it at all. I know Seal Coat is de-waxed and the regular, “clear” Zinsser Shellac is not. Since I often use shellac as my final finish as well, ergo most of the time I’m not bothered by the presence or absence of wax.
So, can I simply dilute the regular, clear Zinsser shellac to synthesize Seal Coat? What would be the ratio of shellac to denatured alcohol? I’ve asked Rustoleum/Zinsser the pound cut equivalent of both Seal Coat and their regular shellac. They say that’s proprietary and won’t reveal it. Has anyone just experimented and come up with anything? Any thoughts? Thanks for your help.
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If you have internet you can look at the material safety data sheet for many of these products. Also Zinsser has a technical data bulletin about this same subject. I don't know who you spoke with but this company puts the information you want out their.
Thanks. Here's the reply to my email received from Rustoleum/Zinsser
Thank you for contacting Rust-Oleum Product Support.
The pound cut information is not available as it is proprietary information however I can tell you that the Seal Coat is a de-waxed shellac and the Shellac is waxed.
If you have any additional questions or concerns please do not hesitate to contact us.
Thank you,
Geoff
I'll look for the technical data bulletin but I'm not a chemist. If its not expressed in terms I can understand, I'm back to experimenting. Appreciate the tip.
Just an FYI,
Highland Woodworking Online sells Seal Coat by the quart. Also, their B&M store is located in Atlanta, GA. That might be a short road trip for you.
Interesting, the fact that Seal Coat was a 2lb cut wasn't a secret several years ago. There are even tables on the internet that help folks cut the stock product even further.
Since you will be putting shellac on top of shellac I would not hesitate to hit Zinsser Clear or other product 50/50 with DNA to make a sealer. I keep Seal Coat handy in 3 squeeze bottles since use it for so many tasks; 1 bottle of straight 2lb cut, 1 bottle of that hit 50/50 and 1 bottle of that hit nearly 50/50 again. another
Proprietary ... that’s kind of silly given how easy it would be to work out for an undergraduate in Chemistry. My guess is that they don’t want to commit, giving them the ability to change it whenever they want.
I was doing some research on Shellac and a few FW articles note that Zinsser sealcoat is a 2lb cut dewaxed. The clear and amber are 3lb cut with wax. An article from Jeff Jewitt in 2014 said a shortage of Clearcoat was due to a poor crop of shellac driving up the price causing some distributors to stop stockin it in favour of the clear and amber.
Yes, Sealcoat is 2lb and their other canned shellac are 3lb. I wouldn't use the waxed version if other finishes are going on top.
I know that the Sealcoat has some isopropyl alcohol in it. I don't know about the other canned types. They also do something to the Sealcoat, and I can't remember what, but it has a much longer shelf life than other shellac, even the mix it yourself varieties.
I use Sealcoat for the first one or usually two coats of pretty much everything. It adds some color and depth under water based finish, which I usually put on top. I never thin the Sealcoat. I find 2 lbs pretty thin already, and have no problem applying it. I honestly can think of no advantage to thinning it, whatsoever.
Over the past several years, I've moved to waterborne top finishes... primarily Deft's Acrylic - usually sprayed; and, I use Sealcoat as the base coat(s) on the raw wood. I've never thought of thinning the Sealcoat, and I can't think of a good reason to do so...
Here is a dilution chart that might be useful: https://www.finewoodworking.com/2007/05/07/mixing-shellac
Is there a reason you don't want to use flake? I use flake as my local stores don't go through cans fast enough (sits on the shelf for years). Flakes are not hard to mix up at all.
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