Shop Test -
Denatured Alcohol
190 Proof Grain Alcohol

By David Knipfer
June 3, 2004

Not that anybody out there cares much for an esoteric topic like this...   but I figured I'd save you some $$$$ and report on my recent test of shellac solvents.

Some of you know that I'm a fan of shellac as a base coat for finishing my boxes.   The solvent for dissolving raw shellac is alcohol.

I've always used denatured alcohol that can be found at any big box store for $2 to $3 a can.

A few months ago our local WW Guild had a presentation by a really knowledgable finishing expert who knows more about shellac than anybody I ever met...   and he claimed that the impurities in Big Box denatured alcohol are poison to shellac...   don't use it.

Soooooo...   I snuck into the liquor store and bought a 750ml bottle of 190 proof grain alcohol...   $11.75 plus tax!.

Well...   I've used up that first batch of 'pure' shellac...   and I say there is no difference that I can tell.

Soooo...   if you are into making your own shellac mixtures...   from my experience that denatured alcohol works just fine at 1/4 the price.

Of course...   my super blonde shellac flakes mixed with that grain alcohol are 100% food safe...   so they did have the advantage of being able to safely drink the finish at the end of a tough day. :)


oxhoward, 06-03-2004 09:27 PM.
I work in the chemical industry and know quite a bit about the production of alcohol and specifically its testing for impurities.

Most denatured alcohol (ethanol) is VERY clean.   The denaturing agent is normally methanol or isopropanol and is added so the material is not fit for human consumption.   There are countless blends.   What would normally "ruin" shellacs are impurities such as silicates, which are a BIG no-no in the coating industry (fish eyes).   Companies (like mine) that produce ethanol blends are VERY careful not to have these around.   The same goes for acetone, and other ketone solvent blends that you can buy at the BIG BOX stores. .

I agree with you whole-heartedly!!!!   Buy the cheap stuff!   Don't worry, drink a homebrew (beer).


DMoening. 06-03-2004 11:30 PM.
When I was in college I mixed a couple super blondes with 190 proof grain alcohol....

I couldn't tell the difference between'em. :)

Dave thanks for the experiment.   I'm at the finishing stage of my kids stepstools and am out of solvent.


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