Klean Strip Denatured Alcohol be suitable for French polishing?

Construction and repair of Classical Guitar and related instruments
SteveL123
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Klean Strip Denatured Alcohol be suitable for French polishing?

Post by SteveL123 » Thu Dec 28, 2017 2:35 am

When it gets warmer outside April- May around here, I want to learn to French polish. I have some Klean Strip Denatured Alcohol left over from flushing an AC system in a car. The MSDS https://www.korellis.com/wordpress/wp-c ... atured.pdf

says its composition is:

Ethyl alcohol {Ethanol} 30.0 -50.0 %
Methanol {Methyl alcohol; Carbinol; Wood alcohol} 40.0 -60.0 %

Will it make a good solvent to dissolve Shellac flakes for French polishing?

jim watts
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by jim watts » Thu Dec 28, 2017 4:04 am

It'll work, but if you can get Kleen Strip Green it would be much healthier for you as it has a much higher Ethanol content.

Bill
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by Bill » Thu Dec 28, 2017 4:11 am

Everclear is 190 proof (95% pure ethyl alcohol), and will dissolve the flakes. It is a bit more expensive than denatured alcohol, but it does not contain the adulterants.
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Michael.N.
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by Michael.N. » Thu Dec 28, 2017 10:12 am

That's an extremely high methanol content, probably fine if you do it in a very well ventilated room and wear suitable gloves. Everclear is certainly a little less harmful but you should use similar precautions.
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simonm
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by simonm » Thu Dec 28, 2017 12:40 pm

I wouldn't use it. Way to much methanol which would seriously scare me. Try and find something with 90%+ ethanol. Some people use an ethanol/acetone mix too. Isopropanol is another option.

Here is a thread which if you skim you will find options. viewtopic.php?f=11&t=102890 I see there that 95% alcohol is not available in NY.

To answer your question exactly. It is probably a very good solvent for dissolving the shellac. It is unfortunately a very good solvent for making yourself very sick. With french polishing your will be exposing yourself to hours and hours of inhaling the fumes very directly. Spend the money. :-)

Alan Carruth
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by Alan Carruth » Thu Dec 28, 2017 9:49 pm

I have gotten ethyl rubbing alcohol at the drug store. It's listed as 70% ethyl alcohol, with acetone, denatonium benzoate, and methyl isobutyl ketone as denaturants, plus water. I would think that it would be relatively harmless so long as you don't ingest it. I have yet to try it as a FP solvent. Given that water is the last listed ingredient it may not have much over the 5% that you get in any ethyl alcohol that has been opened. At very least it could be a way to stretch your stock of Everclear, which is both quite expensive, and harder to get these days than it used to be.

SteveL123
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by SteveL123 » Fri Dec 29, 2017 1:08 am

Thanks for the replies!

OK, so Klean Strip Blue Denatured Alcohol is mostly Methanol which is most harmful if inhaled. Ethyl alcohol {Ethanol} 30.0 -50.0 %
Methanol {Methyl alcohol; Carbinol; Wood alcohol} 40.0 -60.0 %

I plan on wearing appropriate protective mask and do it outdoors so I would not inhale any of it no matter which one I end up using.

I can get Klean Strip Green Denatured Alcohol from Home Depot for $8.40 a quart
MSDS https://www.homedepot.com/catalog/pdfIm ... b04f5c.pdf
Composition:
Ethyl alcohol {Ethanol} 80.0 -90.0 %
Methanol {Methyl alcohol; Carbinol; Wood alcohol} < 5.0 %
Acetic acid, ethyl ester {Ethyl acetate} 1.5 %

There's a Woodcraft not too far from me where I can get BEHLEN Behkol - 1 Quart for $12
MSDS http://www.behlen.co.uk/safety/B650-2816.pdf
Composition:
Ethanol 81-90%
n-Propyl Acetate, Propyl Ester, Propyl Acetate 1-10%
Isobutyl Alcohol 1-10%
isopropanol 1-10%

I can't find Everclear grain alcohol anywhere locally. I do not want to ship it so it's out.

Which of the ones above is best and why? Is one quart enough to practice and learn French polishing on scraps and have enough left over to refinish one guitar top?

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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by James Stephens » Fri Dec 29, 2017 3:44 am

I'll leave those with more experience to answer your question but in case you reconsider shipping, there's a company called Duda Diesel that has their own *denatured alcohol and a 99% isopropyl alcohol that might be worth checking out.

* They have it listed as denatured ethanol and it lists 90.5% ethanol, 4.5% isopropyl alcohol, and 5% NP acetate.
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Michael.N.
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by Michael.N. » Fri Dec 29, 2017 6:50 am

You are OK with your Home Depot $8.40 stuff. It's much less methanol. In fact it's pretty much the same content as the old purple 'methylated spirits' that we had in the UK and elsewhere in Europe and that was used for decades in French polishing, virtually always done without the precautions that I mentioned. Take the precautions and it will be perfectly safe.
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SteveL123
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by SteveL123 » Fri Dec 29, 2017 7:02 pm

James Stephens wrote:
Fri Dec 29, 2017 3:44 am
I'll leave those with more experience to answer your question but in case you reconsider shipping, there's a company called Duda Diesel that has their own *denatured alcohol and a 99% isopropyl alcohol that might be worth checking out.

* They have it listed as denatured ethanol and it lists 90.5% ethanol, 4.5% isopropyl alcohol, and 5% NP acetate.
Thanks for the Duda Diesel suggestion. They sell biodiesel making supplies. Their denatured ethanol 950 mm for $9 has a $11 Fedex ground Hazmat shipping so not very economical. There's a wine shop in Westport CT near me that sells 750 mm of 190 proof Everclear for $18 + tax. I think I am going to start with the Klean Strip Green from Home Depot for $9 / Qt which is convenient to obtain. I'll be dilligent to not inhale any of it.

jim watts
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by jim watts » Fri Dec 29, 2017 8:44 pm

The Kleen strip green works well.

Tom Sommerville
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Re: Klean Strip Denatured Alcohol be suitable for French polishing?

Post by Tom Sommerville » Fri Jan 05, 2018 6:14 pm

It's been awhile since reading the OSHA recommendations, but I determined that I could do everything I needed with three solvents:
everclear 190 for mixing and polishing, acetone for polishing and cleaning, and isopropyl for cleanup and such. These were the safest ones that I could identify based on OSHA s recommendations of maximum concentrations.

The everclear costs about $18., acetone is around $8. and isopropyl is about $4. a quart at the dollar store. The isopropyl is the listed as 91% pure, with water as the inert ingredient. All in all, it works out to little if any added expense for safety's sake, not a bad trade off.

The isopropyl alchohol is sold under the Rexall label. If your familiar with the brand you may be able to find it in town.

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