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| Cheapest way to make up to 99% pure isopropanol |
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| tooki:
By the way, this article from HP (copied from one of several recent flux cleaning threads) says on p.11 that the optimal concentration of IPA for flux removal is 80%, because some of the activators in flux are soluble in water, but not alcohol, and so ~100% solvent will not produce optimal cleaning. As such, this entire exercise in raising the concentration is likely completely in vain. http://hparchive.com/Bench_Briefs/HP-Bench-Briefs-1982-07-10.pdf |
| magic:
It could probably be distilled without a trace of salt but why bother when 99% is available off the shelf. --- Quote from: tooki on July 04, 2019, 02:53:37 pm ---By the way, this article from HP (copied from one of several recent flux cleaning threads) says on p.11 that the optimal concentration of IPA for flux removal is 80%, because some of the activators in flux are soluble in water, but not alcohol, and so ~100% solvent will not produce optimal cleaning. As such, this entire exercise in raising the concentration is likely completely in vain. http://hparchive.com/Bench_Briefs/HP-Bench-Briefs-1982-07-10.pdf --- End quote --- Good to know. Cleaning rosin flux with pure IPA always leaves a bit of white residue. I'll try with some deionized water added next time. |
| Ian.M:
--- Quote from: magic on July 04, 2019, 05:23:21 pm --- --- Quote from: tooki on July 04, 2019, 02:53:37 pm ---By the way, this article from HP (copied from one of several recent flux cleaning threads) says on p.11 that the optimal concentration of IPA for flux removal is 80%, because some of the activators in flux are soluble in water, but not alcohol, and so ~100% solvent will not produce optimal cleaning. As such, this entire exercise in raising the concentration is likely completely in vain. http://hparchive.com/Bench_Briefs/HP-Bench-Briefs-1982-07-10.pdf --- End quote --- Good to know. Cleaning rosin flux with pure IPA always leaves a bit of white residue. I'll try with some deionized water added next time. --- End quote --- In the other recent IPA topic: https://www.eevblog.com/forum/projects/drying-ipa-with-silica-gel-will-this-work/msg2522505/#msg2522505 I posted a link to an IPA concentration vs density (specific gravity) table. 80% IPA by volume would be a density of 0.85 g/ml @20 deg C. Due to IPA's tendency to adsorb atmospheric moisture, if your stock bottle is getting low, or you suspect it has been poorly sealed, I would strongly recommend weighing a known volume to check its density *before* dilution. |
| Brumby:
To date, I've been getting the 2 litre IPA from Altronics which costs $26.95 and I have to drive more than half an hour to get it or pay for shipping. I've never been able to work out what % it is, but it seems to work OK for me. What I have recently found is a supplier in Sydney who offers 5 litres of 100%, 99% or 70% IPA delivered to my door the next day for $29.50 - or I can go for a 25 minute drive and pick it up (for the same price). They also have other sizes including a 200 litre drum of 100% (but that's a bit much for me to handle). I haven't ordered any, so I don't know if there are any hoops to jump through, but I'm not expecting anything too onerous if there are. |
| westfw:
--- Quote --- --- Quote ---I don't know why. --- End quote --- Because 70% is the concentration for optimal effectiveness --- End quote --- I meant "why Isopropyl in the US and Ethanol elsewhere." |
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