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, i have a can of zinnser dewaxed shelac, it says it is a two lb cut .I want to seal the edges of my top before routing my binding channels, and then later use it to french polich the guitar. can someone give me an idea of what ratio to thin down to for french polish ? thanks Jody

I typically use 1# cut for FP. I use Everclear (100% Ethanol) and cut the shellac in half for a 1# cut. For sealing prior to routing, I often use it straight from the can.

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JJ
Napa, CA
http://www.DonohueGuitars.com

Ditto! Everclear is sold in stores that sell booze and is not available in all states/places - it is grain alcohol and lacks some of the additives that make denatured alcohol hazardous.

Jody--

Take JJ's advice if you can get Everclear. Everclear is good stuff, probably the best, but you can't get it in a lot of states. It comes from the liquor stores. You can use a good denatured alcohol from Ace or any good paint store. You should use a glove on your 'padding' hand if you are using denatured alcohol as one never quite knows what the denaturing agent is. Sometimes its just naphtha. Keep the can sealed as alcohol really absorbs water even from the air.

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Jim Howell
Charlotte, NC

Thanks guys ! I appreciate the warnings about the biohazard,looks like its a trip to the liquor store for some ever -clear and that heavier than air stuff . thanks Jody

If you’re smart you get a copy of the MSDS on any chemical you have in your shop. Not only to know it's exact chemical make up but to know the proper handling and first aid treatment. They are provided by the manufacturer at no cost and most are on line. If your doing this as a business and if you have employees or helpers of any type paid or not you are required to have them on file and easily accessible to everyone.

Thanks Micheal , right now I am operating as the lone ranger , but i will keep your advice on file for future refference! Jody

If you're thinking of using it for shellac, I'm not sure it'll work. It works with an oil finish, like Tru-Oil, because oils cure by exposure to air, and water can't spoil it because oil repels water. Mixed shellac cures by evaporation, so even though a coating of heavy gas may slow evaporation of the alcohol, it won't keep the water out because water is also heavier than air. And as we know, alcohol is hydrophilic and LOVES water. It wants to have water's baby. Just limit its exposure to air as much as possible, and you'll be okay. And don't try to French polish in high humidity.

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Carlton Macksam
Muskegon, Michigan

thanks for the additional information ! Jody

[quote="JodyCan someone give me an idea of what ratio to thin down to for french polish ? thanks Jody[/quote]

Jody, I’m not sure if you got your question answered about what ratio to use to thin a 2# cut to a 1# cut using grain alcohol.
100% alcohol is 200 proof and will absorb residual water from the air. 90% alcohol is 190 proof and 10% water, this is most commonly what you get in the liquor store. Everclear is a name brand which my local store doesn't carry. They sell a brand called Gem Clear but it is still 190 proof grain alcohol.

Ronald Louis Fernandez uses a 1# cut for sealing and 2# cut to polish.

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"After forty-nine years of violin building, I have decided that the search for a varnish is similar to the fox hunt. The fun is in the hunt."
Jack Batts Maker and Repairer of Fine Violins

thanks Chuck I will keep that in mind . Jody