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Isopropyl + shellac

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Forum topic by leftcoaster posted 12-15-2019 08:29 PM 775 views 1 time favorited 23 replies Add to Favorites Watch
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leftcoaster

284 posts in 1486 days


12-15-2019 08:29 PM

I found some 99% isopropyl alcohol at ACE. Any reason I shouldn’t use this for shellac?

Alternative is Kleen strip denatured.

Prefer fast drying.


23 replies so far

View AlaskaGuy's profile

AlaskaGuy

5523 posts in 2919 days


#1 posted 12-15-2019 08:37 PM

Isopropyl rubbing alcohol is no good for thinning shellac because it contains about 30% water. The water will cause the shellac to turn white, or “blush.” If you have access to 95-to-100 percent pure propanol or isopropyl alcohol, you could use it for thinning without a problem.

https://thefinishingstore.com/blogs/news/tip-shellac-thinner

-- Alaskan's for Global warming!

View Kazooman's profile

Kazooman

1412 posts in 2562 days


#2 posted 12-15-2019 09:18 PM

Well, Alaska. He did say 99%.

OP. If you want fast drying you should go with ethanol.

View OnhillWW's profile

OnhillWW

209 posts in 1842 days


#3 posted 12-15-2019 09:55 PM

AG has it right. BTW – you will never find 100% ethanol. I worked in a lab and the purist possible is 99.9%; and, as soon as you open the bottle that drops because alcohol has such a strong affinity for water it pulls whatever there is in from the exposed air.

-- Cheap is expensive! - my Dad

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Kazooman

1412 posts in 2562 days


#4 posted 12-15-2019 10:09 PM

Just picking a nit. While you can’t buy 100% ethanol in a can at the big box store, you can, with access to proper equipment and technique, prepare ethanol that is much drier than 99.9%. Very low parts per million residual water can be achieved. The comment about absorbing water on exposure to air are spot on. My favorite way to increase the water content of ethanol is to add a small splash of water to a good single malt whiskey.

View AlaskaGuy's profile

AlaskaGuy

5523 posts in 2919 days


#5 posted 12-15-2019 10:57 PM



Just picking a nit. While you can t buy 100% ethanol in a can at the big box store, you can, with access to proper equipment and technique, prepare ethanol that is much drier than 99.9%. Very low parts per million residual water can be achieved. The comment about absorbing water on exposure to air are spot on. My favorite way to increase the water content of ethanol is to add a small splash of water to a good single malt whiskey.

- Kazooman

And I was just trying to help.

-- Alaskan's for Global warming!

View Lazyman's profile

Lazyman

4545 posts in 1997 days


#6 posted 12-15-2019 11:32 PM

Does DNA also have the same tendency to absorb water from the air?

Shipwright (#24 here) said that he preferred using isopropyl in a thread asking for DNA alternatives since it is almost impossible to find in California (or Canada) these days.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Ted78's profile

Ted78

407 posts in 2609 days


#7 posted 12-15-2019 11:32 PM

I don’t have a good answer for you, I’ve only ever seen 50, 70, and 90% Isopropyl. I doubt 99% would stay that way for long, it absorbs water from the air. BUT this is no different with ethanol, or methanol, all alcohols are hydrophilic ‘water loving’ so I suspect any type of alcohol above 90% or so would work just fine.

-- Ted

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shipwright

8453 posts in 3407 days


#8 posted 12-16-2019 01:00 AM

I just bought a gallon of 99%pure Isopropyl alcohol last week and yes it works great for dissolving and thinning shellac. If you prefer more brush marks by all means use DNA if you can buy it where you are but if you don’t, give isopropyl a try. You might never go back. It also works well for French polishing.

-- Paul M ..............the early bird may get the worm but it’s the second mouse that gets the cheese! http://thecanadianschooloffrenchmarquetry.com/

View Lazyman's profile

Lazyman

4545 posts in 1997 days


#9 posted 12-16-2019 03:09 AM

Sorry to go a little off topic but I often hear people say that as soon as you open a container of alcohol it will be contaminated with water from the air and it always makes me wonder. I don’t doubt that alcohol will absorb some water from the air, It just seems like an extreme statement that is often repeated and I have never heard anyone provide any facts about the phenomenon. I hear similar statements about alcohol/water in gasoline, though that may just be conspiracy theorists. I would think that if you keep your alcohol container closed except when pouring some out, water absorption should be negligible.

Doing the math:
  • At 100% RH at 25° C (~77F), 1 cubic meter of air contains about 20 gram of water.
  • A 1 gallon can is about 0.003785 cubic meters (264 gallons/m3)
  • 1 gallon of air would contain about 0.0757 grams of water at 100%/24°C
  • 1 gallon of Isopropyl alcohol weighs about 2721 grams.

So, unless I screwed up the calculation, in order to raise the water content 1% by weight (27 grams), 1 gallon of alcohol would have to absorb all of the water from 1.36 cubic meters or about 360 gallons of the air.

Perhaps I am missing something.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View smallerstick's profile

smallerstick

28 posts in 1787 days


#10 posted 12-16-2019 12:36 PM

Find a marine supply store and get some stove fuel. That is usually denatured alcohol (ethanol) and is relatively inexpensive.

-- Peter

View Fred Hargis's profile

Fred Hargis

5929 posts in 3103 days


#11 posted 12-16-2019 01:25 PM


So, unless I screwed up the calculation, in order to raise the water content 1% by weight (27 grams), 1 gallon of alcohol would have to absorb all of the water from 1.36 cubic meters or about 360 gallons of the air.

Perhaps I am missing something.

- Lazyman

There’s always someone trying to screw up a good myth with solid facts! :)

-- Our village hasn't lost it's idiot, he was elected to congress.

View Dark_Lightning's profile

Dark_Lightning

3766 posts in 3718 days


#12 posted 12-17-2019 01:39 AM

Any alcohol will mix with water. If one uses a closed container and pours out what is needed and then closes the container, it will be a long while before the alcohol is significantly “contaminated” by water. Not having seen the discussion about isopropyl alcohol, where can one buy that at a decent price? We used it at work to clean spacecraft parts, but I don’t need it that pure. Reviewing the thread, I’ll look at ACE for some isopropyl alcohol. I will also note that denatured alcohol isn’t just ethanol. It has a bitterant added to keep people from drinking it. If it was pure ethanol, it would require a tax stamp. We used that for cleaning the lenses of spacecraft optics, and a five-gallon can (with a tax stamp) seemed to evaporate much quicker than one would expect. Heh heh heh. Wasn’t me, though. I like to keep my wits about me around that kind of expensive hardware.

-- Steven.......Random Orbital Nailer

View shipwright's profile

shipwright

8453 posts in 3407 days


#13 posted 12-17-2019 05:54 AM

Steven, I get mine at a feed store. They sell it as horse liniment but it’s 99%pure isopropanol.

-- Paul M ..............the early bird may get the worm but it’s the second mouse that gets the cheese! http://thecanadianschooloffrenchmarquetry.com/

View CaptainKlutz's profile

CaptainKlutz

2263 posts in 2104 days


#14 posted 12-17-2019 06:54 AM

+1 Isopropyl Alcohol 99% works
Feed store Isopropyl Alcohol is usually cheaper than hardware store too.
Try looking for a Farm & Fleet, or Tractor Supply Corp (TSC).

+1 Another source for denatured ethanol alcohol is ‘stove fuel’.
Sold at camping and marine stores.

From another thread on this is topic; if you use DNA, use the GREEN label version from Keenstrip, not the red label. It has less methanol alcohol and dries with less streaking when brush shellac.

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

View OnhillWW's profile

OnhillWW

209 posts in 1842 days


#15 posted 12-17-2019 02:26 PM

I never said that water absorption would be such that it would alter the product enough to matter – my point was that it is not sold in a100% formulation because it is so hydrophilic and if it is stated to be 100% it is false advertising. Whether 99.9% or 99% or 90%, it will not make any real world difference to us when thinning finish.

Ethanol fumes are less harmful (less harmful) than isopropyl so I always go that route – it’s your liver treat it to whatever you want.

-- Cheap is expensive! - my Dad

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