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BobW

Active Member
Coincidentally, the methanol that I have is also sold as fuel line antifreeze. I'd forgotten that they've migrated to IPA, because methanol causes problems with fuel injectors. I'll have to check out the auto supply store as soon as they're open for business again.
 

gophert

Well-Known Member
Most Helpful Member
Coincidentally, the methanol that I have is also sold as fuel line antifreeze. I'd forgotten that they've migrated to IPA, because methanol causes problems with fuel injectors. I'll have to check out the auto supply store as soon as they're open for business again.
the convenience store at the corner gas station is likely open.
 

BobW

Active Member
Yes, but they'd only have in little bottles. I'm looking for the 4 litre jug.
Meanwhile, I remembered that I have a 10 litre jug of plumbing antifreeze—denatured ethanol—which would probably be fine for this application, except that it's likely diluted with water, and I don't have a suitable hydrometer to test it.

BTW, handy trick for converting 70% or 90% IPA to 99% IPA: Add a little bit of ordinary table salt (NaCl) to it and shake it up. The salt combines with the water and separates out. The pure IPA floats on top and can be decanted off.
 

gophert

Well-Known Member
Most Helpful Member
We had some students try that a long time ago. i don't remember the result.
 

BobW

Active Member
I've tried it. It works remarkably well. You can clearly see the division between water and IPA. Just like oil floating on water. Unfortunately, it doesn't work for ethanol. I just tried it, and nothing happened.
 

Pommie

Well-Known Member
Most Helpful Member
You can work out the S.G. and hence the percent alcahol the old way, weigh a known volume. If you're not certain of a volume then weigh empty and filled with water. Should be a doddle for a man of your caliber. :D

Mike.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
IPA still seems to be readily available on ebay.

eg.
 

BobW

Active Member
You can work out the S.G. and hence the percent alcahol the old way, weigh a known volume. If you're not certain of a volume then weigh empty and filled with water. Should be a doddle for a man of your caliber. :D

Mike.
It's not that easy to do when there's not a big difference between between the SG of the two components. However, I decided to give it a shot, using a digital kitchen scale with a resolution of 1 gram, and a 150 ml graduated cylinder. The SG came out to 0.967, which is just barely within the range of my hydrometer after all. So, measuring it with the hydrometer, I get SG of 0.972 which should be more accurate than the scale method.

Assuming that the antifreeze is only alcohol and water, then the percentage comes out extremely low: less than 15% alcohol. There may be another component in the mix such as propylene glycol which has a SG > 1. I poured a sample into a saucer to evaporate and see if a heavier component emerges. No results yet. But, in any event, this stuff will be useless for cleaning.

As for getting IPA locally, I haven't made a serious effort yet. Drug stores and grocery stores are still sold out. I'll need to go to an auto supply store to get IPA in 4 litre jugs, and I'm not sure whether they're open for business yet. Anyway, I've got other things I can work on for now.
 

gophert

Well-Known Member
Most Helpful Member
IPA still seems to be readily available on ebay.

eg.
I'm not sure I'd call 50£/5 liter bottle "available". It is IPA! not extra virgin olive oil from a remote Greek Island.
IPA should be selling under $10 per gallon for single-gallon quantities.
 

BobW

Active Member
The operative phrase is "Lab Grade," free of mystery contaminants, suitable for controlled chemical processes, etc. That jacks up the price tremendously.

I think I've just found a local source of denatured ethanol for less than half the price of normal IPA.
 

Pommie

Well-Known Member
Most Helpful Member
I nearly bought 5Ltr of IPA off ebay for AU$25 (US$13) about 4 months ago. Now, 100mL is AU$20!!!

Mike.
 

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