90% isopropyl alcohol

Aadecktor · Sun Nov 15, 2020 7:32 pm

I’ve been trying to get away from using acetone for cleaning my material. I’ve heard of people using 70% alcohol, but I recently scored a 5 gallon jug of 90% from work. Are there any issues with cleaning with this?

Poland308 · Sun Nov 15, 2020 8:30 pm

That’s what I use 90% of the time. Unless I need extra clean.

LtBadd · Sun Nov 15, 2020 8:52 pm

I always use 90% IPA, unless it's a critical weld or the oil/grease is heavy, even then I start with the IPA to get most of the contaminate off, and finish with acetone.

taylorkh · Mon Nov 16, 2020 8:55 am

Just remember... 90% isopropyl alcohol is flammable.

Ken

BugHunter · Mon Nov 16, 2020 9:36 am

taylorkh wrote:Just remember... 90% isopropyl alcohol is flammable.

Ken

Highly...

Aadecktor · Mon Nov 16, 2020 10:48 am

Right on!

Mon Nov 16, 2020 2:56 pm

Isn't acetone flammable as well?

BugHunter · Mon Nov 16, 2020 3:49 pm

weldin mike 27 wrote:Isn't acetone flammable as well?

Yes it is. But I'd say alcohol is more likely to make people careless because the 70% stuff we normally use, isn't flammable.

Louie1961 · Mon Nov 16, 2020 5:21 pm

70% stuff we normally use, isn't flammable.

I would beg to differ.I used 70% Isopropyl (rubbing alcohol) as fuel in my spud gun all the time. It burns quite well.

BugHunter · Mon Nov 16, 2020 9:12 pm

Louie1961 wrote:
70% stuff we normally use, isn't flammable.
I would beg to differ.I used 70% Isopropyl (rubbing alcohol) as fuel in my spud gun all the time. It burns quite well.

Hmmm...

Not doubting you here, I know hairspray Works real well in a spud gun. I don't know how 70% would have worked. Maybe the vapors, after it sits for a while are more flammable.

I just took a lid off a gatorade bottle and put some 70% in it. Put it on the sidewalk and hit it with a propane torch. Until I put the torch flame right in it, it did not light. Once lit, it was a very slow, very weak flame. It never melted the lid. The lid was probably 7/16 of an inch tall, 3/8 deep, and the flames barely rose above it.

I've used a fire extinguisher to put out 90% in the past so I can say there is a very big difference between the two. I have some 91 upstairs but I didn't bother lighting that up.

I poured some 70% on the sidewalk which is of course cold outside. I had to keep the torch aimed at it for several seconds to get it to light. I'm wondering if it wasn't too cold to evaporate enough alcohol so it could light. Maybe the torch warmed up the concrete and then it would burn. It did burn for a little while and was a pretty cool experiment all things considered.

Spartan · Mon Nov 16, 2020 9:42 pm

I use 90% IPA quite often for metal prep. I also always keep a bottle on hand of 90% IPA mixed 50/50 with acetone as a cleaner that is sort of "best of both worlds" and not too harsh especially if working near any plastics. That 50/50 mix is also an excellent flux remover for soldering.

I use 70% IPA for the initial cleaning of parts that are particularly dirty. The higher water content is ideal for that since it dissolves dirt and helps to wash it away.

JayWal · Mon Nov 16, 2020 10:21 pm

Whats the advantage of the 90% over acetone?

I dont do much tig, so i don't use a lot of either

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Spartan · Mon Nov 16, 2020 10:28 pm

JayWal wrote:Whats the advantage of the 90% over acetone?

I dont do much tig, so i don't use a lot of either

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For me, 90% IPA is just cheaper, more readily available, and is less caustic (better for your skin, won't melt some plastics, latex gloves, etc.). However, I do also use straight acetone quite a bit.

hey_allen · Tue Nov 17, 2020 2:02 pm

Would Denatured Alcohol work as well?
I don't know what is used as the "denaturing" additive to make the alcohol non-potable, but would think that any 90%+ alcohol should work as a passable cleaner.

Around my area, getting any high proof alcohol has become difficult with the virus going around and people buying up any/everything for cleaning purposes.

Louie1961 · Tue Nov 17, 2020 3:35 pm

Whats the advantage of the 90% over acetone?

In 1981, when I took Organic Chemistry in college, we used acetone to clean our glassware before and after experiments. Back then they used to make us use it under a fume hood, and we were told that breathing it would give you liver damage. I don't think that is true, but I suspect it is that sort of thinking that will have some people interested in using isopropyl alcohol over acetone.

LtBadd · Tue Nov 17, 2020 5:28 pm

hey_allen wrote:Would Denatured Alcohol work as well?

Yes, maybe not for code work but it does the trick.

sbaker56 · Tue Nov 17, 2020 7:57 pm

The nice thing about isopropyl is while not as aggressive as acetone, it doesn't evaporate away nearly as fast, but still dries fast enough it doesn't become an inconvenience. I doubt I'm the only one to have SOAKED a paper towel in acetone only for it to start drying before I was done cleaning, or even started.

LtBadd · Tue Nov 17, 2020 8:29 pm

sbaker56 wrote:The nice thing about isopropyl is while not as aggressive as acetone, it doesn't evaporate away nearly as fast, but still dries fast enough it doesn't become an inconvenience. I doubt I'm the only one to have SOAKED a paper towel in acetone only for it to start drying before I was done cleaning, or even started.

I have chemical resistant gloves for using acetone, although they are a bit cumbersome, I use the IPA probably 80% or more of the time, most of the parts I weld are machined stainless, so nothing too dirty

Wed Nov 18, 2020 2:42 pm

I've also heard that acetone is quite nasty. I believe that people think that if something evaporates, that it's somehow safe.

Side note, in Australia, we call denatured alcohol, methylated spirits.

BillE.Dee · Wed Nov 18, 2020 8:00 pm

Quick note....tonight went to walmart...denatured alcohol is $.60 more per quart than acetone.

LtBadd · Wed Nov 18, 2020 9:41 pm

BillE.Dee wrote:Quick note....tonight went to walmart...denatured alcohol is $.60 more per quart than acetone.

So what's the take away, buy IPA?

BugHunter · Wed Nov 18, 2020 10:19 pm

LtBadd wrote:
BillE.Dee wrote:Quick note....tonight went to walmart...denatured alcohol is $.60 more per quart than acetone.
So what's the take away, buy IPA?

Yep. I'm drinking one right now.

BillE.Dee · Thu Nov 19, 2020 7:38 am

dunno Richard,,,didn't get into the area with ipa to compare the price of that against the others. the queen said, LET'S GO!
I "try" to not get into the affluence of incohol as some thinkle peep I do it too often.

buggy, IF I didn't live 2 hours out, I'd be over to help.

clavius · Sat Nov 21, 2020 10:29 pm

hey_allen wrote:Would Denatured Alcohol work as well?
I don't know what is used as the "denaturing" additive to make the alcohol non-potable, but would think that any 90%+ alcohol should work as a passable cleaner.

Around my area, getting any high proof alcohol has become difficult with the virus going around and people buying up any/everything for cleaning purposes.

I believe that the denaturing agent is typically methanol, hence the name "methylated spirits" used in some places as noted in an earlier reply.

Sat Nov 21, 2020 11:00 pm

clavius wrote:
hey_allen wrote:Would Denatured Alcohol work as well?
I don't know what is used as the "denaturing" additive to make the alcohol non-potable, but would think that any 90%+ alcohol should work as a passable cleaner.

Around my area, getting any high proof alcohol has become difficult with the virus going around and people buying up any/everything for cleaning purposes.
I believe that the denaturing agent is typically methanol, hence the name "methylated spirits" used in some places as noted in an earlier reply.

yes, tho there was a move here years ago to leave the methanol out to stop people getting poisoned by it ie from drinking it.

however afaik ethanol is a poorer cleaner than ipa or acetone.