Isopropyl alcohol versus denatured alcohol or EverClear?
danvgs
| Posted in General Discussion on
Has anyone tried Isopropyl alcohol for mixing with shellac flakes? How does it compare to denatured alcohol or 180 proof alcohol? I can buy 91% from the local drugstore cheaper than the other 2 options. I’m just wondering?
Replies
Denatured has dangerous chemicals that I would avoid at all cost.
Nearly pure ethanol or ever clear would be my first choice.
+1 for Everclear. isopropyl never
Denatured alcohol is Ethanol (grain alcohol) which has some denaturants to make it non-drinkable. So if you are not intending to drink it don't worry about it. It works well with shellac. Isopropyl alcohol is a different animal altogether and should not be used in woodworking. It has a much lower concentration of alcohol and also contains water, not a good thing for woodworking. Everclear is pure Ethanol (grain alcohol) and in some states a license is required to buy it. If you can buy it cheaper than denatured alcohol go for it otherwise I wouldn't bother.
Noooo. Denatured can be a lot of things. It often has methanol in it. And "just don't drink it" is not a valid warning. Those chemicals don't need to be swallowed to cause harm.
I use 99,9% methanol for diluting shellack, the denatured alcool here is 90% ethanol, 10% methanol but it’s hard to find.
Isopropyl does work for shellac flakes and I have used it for that, but meths or DNA is far better. With the former, dissolution is much slower and so is drying so you lose some of the benefit. Finish effect is similar in my experience.
I don't think the small cost saving is worth it.
On the harmlessness of DNA - most is denatured with methanol as this hardly alters the working properties but tastes foul and causes blindness and death if consumed in large quantities frequently.
Studies have shown that you can get significant methanol exposure at 200ppm in air for 4 hours but that this probably does not reach concerning levels of formic acid production.
200ppm is a LOT - think a soaked flannel in a closed garden shed level.
Strictly speaking then, you can absorb methanol in the lungs, but at any reasonable level of use it is insufficient to cause harm - the body has enzymes which break down the toxic products of methanol metabolism and these are completely effective where the dose is small.
With good ventilation (an open window will suffice) it is hard to envisage any way other than spraying you could come to harm from using DNA for shellac.
Spraying at high volumes - well over that which is achievable with rattle cans - could easily generate very high levels of methanol in the air so excellent ventilation and a respirator are essential for spraying large areas. An N95 mask will stop droplets and shellac getting into your lungs, but will not stop methanol. That needs a proper filter - a respirator with a black or yellow labelled cartridge will do.
Thanks, rob_ss, I appreciate the science in your comments.
According to the manufacturer (3M) filter/cartridge respirators for methanol vapors are not effective. I have spoken with tech support at 3M and they state that for methanol, cartridge respirators are not effective. The cartridge (black or yellow) has too short of a service life. Their (3M) recommendation for protection from Methanol vapor is to use a supplied air respirator. Here is a link to 3M's Respirator Selection Guide https://multimedia.3m.com/mws/media/639110O/3m-respirator-selection-guide.pdf Methanol is on page 59. So I would not count on filters for protection if there are significant levels of Methanol present.
Agree 100%. Under normal circumstances, the amount of methanol exposure is essentially harmless, as the body easily deals with the metabolite, which, as you say, is formic acid. So, don't be greatly concerned about using DNA.
And isopropanol works to dissolve shellac. Just don't used the drug store type, as it contains 30% water, which is a no-no with shellac.
In terms of the toxicity of alcohols, the number of carbon atoms is the key; those with odd numbers of carbons will have toxic properties, those with even numbers, much less so. Methanol (1 carbon) metabolizes to some formic acid and some formaldehyde. Ethanol (2 carbons) goes to acetic acid (vinegar) and acetaldehyde. I recall in 1964 eating some dodecanol (12 carbons) in an organic chemistry class. As I recall it was a waxy semisolid.
+1 Everclear (their are other 190 proof brands as well).
Isopropyl alcohol works ok if you can get the 96-99% kind. The standard 70% kind is not so good (too much water).
I prefer to use Lagavulin.
:)
Enough of that and you won't care about the finish! A fine choice...
Good one. Both the comment and the single-malt.
The 16 or 8 year old?
I've used all three and all three work just fine. My preference is 190 proof drinkable alcohol. My though being 190 proof drinkable alcohol is likely the least harmful to my health to breath. Was working with 190 proof drinkable alcohol dissolved shellac this weekend. I keep the garage and side doors open to get better ventilation. Often, I will use isopropanol to clean the brush when I'm finished.
Years ago I used my papaws moonshine.
Not really but I bet that stuff would have worked.
GO VOLS
Isopropyl alcohol can be used as a solvent for shellac flakes, but it is not as effective as denatured alcohol or 180 proof alcohol.
Denatured alcohol is a type of ethanol that has been mixed with small amounts of other chemicals, such as methanol or isopropyl alcohol, to make it unfit for consumption. It is the most commonly used solvent for shellac flakes because it dissolves the flakes more easily and dries more quickly than other types of alcohol.
180 proof (or 90% pure) ethanol is also a suitable solvent for shellac flakes, and it can be purchased from liquor stores or online retailers that specialize in high-proof alcohols.
While isopropyl alcohol can be used as a solvent for shellac flakes, it may not dissolve the flakes as quickly or thoroughly as denatured alcohol or 180 proof alcohol. Additionally, isopropyl alcohol contains water, which can affect the drying time and quality of the shellac finish.
I use Mohawk shellac reducer.
There's nothing wrong with DNA, either. You're not ingesting it!!
Personally I use Johnny Walker Blue, a little for the shellac, a little for me. Looks good to me, especially after two glasses.
. . . and adds a bit of warm amber color to wood.