Canned shellac

[Daniel Kurtz]

Is canned shellac, of the type sold in hardware stores, of any use? I think the brand that's most common around here is Bullseye. Or is it hopeless and should we all buy flakes?

Thanks.

rabbit

[Waddy Thomson]

Zinsser Seal Coat is a dewaxed shellac. It works fine for spraying or French polishing. I sometimes use it for spit coats before I start the polishing process. It's a bit darker than the lightest blond shellac. I like the tint it gives.

[Chuck Tweedy]

IF it is fresh - then it is fine stuff.
That is the caveat.
I don't know how to tell if it is old other than to put some on glass and see if it forms a hard film.

[Charlie Schultz]

Zinsser claims the shelf life of their current product is 5 years(!).

The below info on how to interpret their date code (bottom of the can) is 3-4 years old, not sure if it is still accurate.

The batch code on the shellac should always be a 6- or 7 digit number, beginning with a letter. For example: S01231D
The letter indicates plant of origin.
The first number after the letter will be the last digit in the year of manufacture
The second character will correspond to the month; O, N or D for October, November or December, otherwise the single number for the month.
The third and fourth numbers will relate to the actual day of the month.
In this case a batch code reading S01231D will have been made in the year 2010, in the month of January, on the 23rd day.

[Daniel Kurtz]

OK, so I see that Zinsser and Bulls Eye are the same thing. It looks like it comes in 'clear' and 'amber'. Can anyone say how 'clear' the 'clear' is? I'm looking at a guitar body that's already got some color on it - the finish was either never completed, or it was partially stripped off... either way, I think it's interesting and want to use it. Also, I'd like to try working with recovered/salvaged materials, which might have remnants of previous finishes (paint etc). From what I've been reading, shellac might be the best choice for using as a sealer/filler on these materials because it sounds like it's compatible with just about everything in the universe. But anything with a tint in it might not work because it could alter the existing colors.

I appreciate people's thoughts.

rabbit.

[Waddy Thomson]

Remember, if you want de-waxed shellac, the only ones that will be de-waxed are the one marked Seal Coat, or the spray can. The others contain wax. Not saying wax is bad for French polishing, but it won't work under other finishes.

[Mark Swanson]

Use only the Zinsser Seal Coat. The other Bullseye stuff has additives, besides the wax. The only pure stuff is the Sealcoat.

[Daniel Kurtz]

Thanks Mark. Extremely useful to know. See, this is one of the things that makes dealing with finishing materials so hard: sometimes it just seems impossible to determine just what stuff is. On the Zinsser web page for what they call 'Sanding Sealer' they nowhere indicate that this is in fact shellac... though you can see on the label of the can in the picture that it is '100% wax-free shellac'. They don't tell you anywhere in the description of the product they DO call shellac that it NOT de-waxed, but I suppose you can assume that if they don't say it, then it isn't. Then there's the stuff they call 'B*I*N Sealer" which is either de-waxed shellac, 'shellac-based' (with what else?), or synthetic (??) shellac. And this is on their web site!! A trip to the finishes/paint aisle of the hardware or home improvement store is like a trip down the rabbit hole.

[David King]

You can mostly de-wax any shellac by simply letting the wax settle out of solution to the bottom of the can. When the shellac looks transparent it should be wax free. Scoop out what you need as if you were skimming the fat off your gravy. I haven't had many issues with adhesion using waxed shellac so I'm not sure it's that big a deal.

[Michael Brose]

Is it ok to cut the canned stuff? It said not to thin on the can, but I was reading the canned stuff is usually 3-4lb cut ( On Stew Mac). Just curious

[Michael Lewis]

Whether to thin or not depends on your intended use. I usually thin the first coat significantly whatever material I am using. You need penetration to get good adhesion, and thicker material often doesn't penetrate as well as thinner material. This causes finish adhesion issues all too often.

[Michael Phillips]

I plan on using Chemcraft pore filler on a walnut body. The directions say to seal the wood first. My local hardware store only has the Zinsser Shellac, not the Zinsser SealCoat. Is the shellac OK to use as a sealer or do I need the de-waxed version? Thanks.

[Daniel Kurtz]

I usually thin the first coat significantly whatever material I am using.

Do you thin with just denatured alcohol?

rabbit

[Michael Lewis]

Yes, thin shellac with denatured alcohol. Thin lacquer with lacquer thinner, oil varnish with terps or mineral sprits, etc.

[Gilbert Fredrickson]

I am currently using Zinzer canned shellac to finish a Sapele/Lutz parlor guitar. I applied a wash coat, let it dry 24 hrs, filled the pores on the body 3x, letting each filling dry overnight, before slathering on multiple coats of shellac. I've sanded the surfaces flat and applied three more coats of shellac. Now I am wondering how I will finish this instrument to a silky smooth semi-gloss finish. Looks good, so far.