Shellac trouble, help!

cmjohnson

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I'm working on a restoration of an '80s Hamer Steve Stevens model guitar for a friend.

Dispensing with the details that may be interesting but don't really matter, here's the problem.

For this one I want to use a shellac ground coat under the touch-ups. (Full neck refin plus some other spot work on the body.)

But my shellac (obtained from stewart-macdonald) won't melt! Following the directions, it's not melting hardly at all, using either straight denatured alcohol or the highest proof ethanol I can get locally, 175 proof.

So, is 175 proof too low and does denatured not work well? Is that it, or do I have a bad batch of shellac?
 

Wallied

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A quick googling tells me 175 proof equals 100% alcohol, so no problems there. The flakes take from an hour to overnight to dissolve, depending on the amount. But a picture would be a good hint for me to give a more educated guess on your problem.
-How much shellac and alcohol did you use?
-How long did you give it time to dissolve?
-Did you shake the container every once in a while?

regards, Will
 

the great waldo

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This might sound daft but make sure you didnt mix alcohol with bone glue flakes, it happened to me once when I didnt read the label on the jar and mixed alcohol up with stewmac hide glue which does look like blonde shellac. It took me a while before I had figured out what I had done. Live and learn I suppose!!!
cheers
Andrew
 

cmjohnson

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It's not bone glue flakes. I don't use anything but Titebond, ever. Unless I'm working on a violin and I haven't done that in years.

Proof is twice the alcohol percentage. I thought everybody knew that? 200 proof is pure alcohol. 80 proof is 40 percent.

I know that the mixed shellac has a shelf life but it's been together so long, without appreciable amounts of shellac dissolving, that it's probably past its shelf life.

Since it's not dissolving the effective cut is very low. I was trying for a 1 pound cut.

I'm asking again, is 175 proof high enough? Does denatured work with it?

It appears from some searching I've done that I've got an old batch and it's not going to dissolve well,
so I'm just going to scrap it and start with freshly ordered shellac and a quart of true reagent grade ethanol from a chemical supply house.
 

Ripthorn

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I have never had a problem with dissolving fresh flakes in denatured alcohol. I've never tried to use old flake, but I do recall reading that even in flake form, it can begin to become less effective over time.

When mixing mine, I usually mix a 2 lb. cut and it takes 1-2 days at room temp to dissolve, giving it a good swirl every couple hours or whenever I remember.
 

jkes01

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Send StewMac an email. They are pretty good about responding.
 

Subterfuge

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I bought Everclear in New Jersey, I believe it's 195 proof and 97.5% pure ethanol .. six bucks for a big bottle
 

Subterfuge

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over time, alcohol, which has an affinity for water, will absorb it and become useless. Anhydrous alcohol ( unopened Everclear) has had all of the water removed, hence 195+ proof (97.5%+ alcohol). It is only high proof when you first use it, it then starts taking in water (hydroscopic) and the proof drops. Alcohol (ethanol) dissolves 85-98% of the shellac. Testing for proof, when a sample is shaken; higher proofs form bubbles that immediately go away, lower proof the bubbles linger ....
 

Subterfuge

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ok I found out that Everclear StraightGrain alcohol ( 190 proof, 95% alcohol, 5% water) is the preferred solvent for mixing shellac, furthermore, make sure it is 190 proof as it is also available in 151 proof EverClear (75.5% alcohol, 24.5% water), which is too much water, which will not work as a shellac thinner
 

Wallied

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Sorry for my mixup on the proof. Here in Finland we speak only of percentages (alcohol by volume), so in my hurry while googling I mixed degree proof spirit as used by the British in the past with the abv-based American proof rating.

Still hoping the whole world used same units and markings ;)
 
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Pleximan

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You can get 99% isopropyl alcohol at most pharmacies or 91% at the very least. That would dissolve shellac.
 
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CB91710

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ok I found out that Everclear StraightGrain alcohol ( 190 proof, 95% alcohol, 5% water) is the preferred solvent for mixing shellac, furthermore, make sure it is 190 proof as it is also available in 151 proof EverClear (75.5% alcohol, 24.5% water), which is too much water, which will not work as a shellac thinner
And 190 is not available in every state.
California limits spirits intended for consumption to 151. I had to go to AZ to get a bottle of 190 for dehydrating briar smoking pipes.
 


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