# Rubbing alcohol or denatured alcohol?



## thejosh (May 14, 2011)

Hey you woodworking people from around this beautiful earth sphere!

I gotta question. I just used shellac (Zinsser, bullseye) on a sweet box I made for a guy I know. I had never used shellac before. I assumed warm soapy water would clean my brush. I was way wrong and the brush quickly seized up, becoming rock hard. I looked on the back of the can and it said to use denatured alcohol for brush clean-up. I remembered I had some rubbing alcohol (isopropyl alcohol) from last semester's online Botany lab kit (don't ever take an online Botany class (shudders)). So I was able to rid the brush of the congealed shellac but it took a while.

Would denatured alcohol work faster? Or is rubbing alcohol just as good?

Thanks for your input.


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## shipwright (Sep 27, 2010)

Any alcohol will dissolve shellac. For cleaning it's not too important. 
For dissolving flakes or diluting however the different alcohols will give different characteristics. The critical thing is purity. You want alcohol, not water. Look for 99% pure.

Methyl alcohol (methanol, methyl hydrate) is the most volatile and drys too fast to be of much use except for cleaning in a pinch.
Ethyl alcohol (denatured, ethanol, Stolichnaya, Jack Daniels) is slower and is the norm.
Isopropyl alcohol ( isopropanol, rubbing) is slower yet and IMHO is a little easier to use in some applications. I like it for French polishing.


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## dawsonbob (Aug 5, 2013)

Something that I learned here on LumberJocks is that you can clean your brushes with plain old sudsy ammonia. It worked just fine for me.


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## thejosh (May 14, 2011)

Thanks, you two.


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## MalcolmLaurel (Dec 15, 2013)

Just to add a couple of things: "Rubbing" alcohol sold in stores is isopropyl alcohol cut with water; the most common types are 70% alcohol (thus 30% water) or 90%. With the added water, neither are suitable as a thinner. Pure isopropyl alcohol is much harder to find.

"Denatured" alcohol is ethanol (ethyl alcohol) cut with a very small amount of methanol (methyl alcohol) to make it toxic, so people don't drink it without paying liquor taxes. This is the usual shellac thinner, readily available in hardware stores.

Methanol is toxic, and also not readily available in pure form.


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## wapakfred (Jul 29, 2011)

If you intend to dedicate that brush to shellac use only, there's no reason to clean it. Let it set up, and store. The next time you need it, let it sit in your shellac for a several minutes; it will come right back to life. But as mentioned above, ammonia is an excellent cleaner and a lot cheaper than using DNA.


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## Skylark53 (Jan 8, 2010)

Josh, that's all good advice for you. How did you like using the shellac? I had not used it in years until seeing here on LJs that its still the finish of choice for many experienced and accomplished woodworkers. I use it often now. I still have a magazine rack I built (actually assembled with a good bit of help) about 50 years ago at VBS.


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## ssnvet (Jan 10, 2012)

*If you intend to dedicate that brush to shellac use only, there's no reason to clean it. Let it set up, and store. The next time you need it, let it sit in your shellac for a several minutes; it will come right back to life.*

this is AWESOME to know…. I'm digging a brush out of my trash can tonight…. Thanks for sharing.


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## wapakfred (Jul 29, 2011)

Funny place to store it (LOL).


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## shipwright (Sep 27, 2010)

*Malcolm*, I have found 99% pure isopropyl alcohol in gallon jugs being sold as horse liniment.

*+1 Fred*, I am terrible with cleaning brushes but I have a really expensive one from Tools for Working Wood for shellac because shellac will forgive me for neglecting it. .......


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## Vincent (Mar 10, 2009)

+1 to MalcolmLaurel. Rubbing alcohol contains too much water. Denatured ethanol can contain methanol (poison) or ethyl acetate (lacquer thinner) or toluene. Pure ethanol is often sold as Everclear and in many states requires a liquor tax stamp.


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## distrbd (Sep 14, 2011)

Shipwright is right on,99% alcohol for thinning/mixing works like a charm,I use household Ammonia to clean the brush,but Mainiacmatt gave me a new tip.I hate the smell of Ammonia.


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## thejosh (May 14, 2011)

Thanks everyone! I will keep that brush dedicated to shellac then. Good to know. Rick, not sure if I like the shellac, though. Well, Im not that experienced with it yet, obviously. What I did do, however, was after the second coat of shellac on the money-clip box, I sanded it very lightly with 320 sandpaper and that took out any remaining specks. It is very smooth and doesn't look scratched from the sandpaper.


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## Knothead62 (Apr 17, 2010)

FWIW, I used denatured and 91% rubbing alcohol for cleaning up epoxy. Both work great. Buy some of each and test them for what you are going to be doing. Let us know the results.


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## mcoyfrog (Jul 23, 2008)

whoa thats cool i didn't realize you could just leave it in.. WOW I use shellac all the time i'm doing that…

I just buy the 3lb cut shellac then mix it with denatured alcohol for my base finish,(about 3:1 so each coat drys really fast) after several coats of this with sanding in between finish it off with a wipe on poly and walla awesome finish with little fuss. Kind of a modern french polish LOL


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## kelvancra (May 4, 2010)

Malcolm, Regarding your statement "I have found 99% pure isopropyl alcohol in gallon jugs being sold as horse liniment," I hope the liniment you found was cheaper than what I found ($120.00/gal). The denatured alcohol I find in the big box stores only runs around fifteen a gallon.

I'm down to my last gallon, or two. Sears had gallons they were clearing out for "$1.00 per gallon," so, of course, I bought all ten gallons of it.


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## shipwright (Sep 27, 2010)

Yes, the isopropyl alcohol I found as horse liniment was very, very much less than $120/ gal.
Denatured alcohol is notoriously hard to find in Canada. That's what led me to experiment with isopropyl.


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## TopamaxSurvivor (May 2, 2008)

Paul, It is sold by the gallon in Lowes and /or Home Depot. You could probably smuggle a gallon or 2 when you go home ;-))


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