Mixing a shellac cut?

Question

This might sound like an obvious question to a lot of woodworkers, but I'm seeing some differing definitions on the web.

What is the formula for a "shellac cut", i.e. mixing your own shellac?

For example, this video defines a "2 lb cut" as "2 lbs of flakes dissolved in 1 lb of alcohol". In other words, shellac/alcohol.

However, the admin on this forum describes it similarly, but uses very different units when he writes, "2 lbs of shellac to one gallon of alcohol".

Now, since "1 gallon of alcohol" is about equal to 6.7 lb, that would make his example closer to a 2/6.7 = 0.23 cut which seems very diluted by the other definition.

I tried mixing my own shellac using the second definition, using 33g of shellac flakes and 183g of iso alcohol, for roughly a 0.18 lb cut, and found it to be basically unusable. It's so watered down, it's like just putting alcohol on wood.

Am I correct in understanding the first definition is the correct one?

Answer 1

It's pounds of shellac per gallon. Yes, a 1-pound cut is extremely light; the lightest I've heard commonly used is 2-pound and traditional "shelf standard" (including premixed stabilized such as sealkote) is 3-pound, commonly diluted to taste before use.

Remember that you don't need to, and usually shouldn't, mix a whole gallon at once. But you can't just divide both numbers by the same factor since they have different density and you're using weight for one and volume for the other. 2 oz. of flakes in 8 oz. of alcohol is also a 2-lb cut.

Websearch will find both tables for the proper mixtures and ratios for dilution if you want a named result rather than "that looks about right".