Is acetone or isopropyl alcohol better for removing rosin flux?

For removing rosin flux from my board, should I use Acetone or Isopropyl Alcohol? I need an easily available solvent.

• IPA is widely used for removing flux, I'd say go with that. Acetone can dissolve certain plastics, it may be too aggressive for cleaning a PCB (but I haven't tried). – marcelm Jul 17 '17 at 11:03
• @marcelm If you want to answer the question, please do so in the appropriate place. Comments are for requesting clarification or pointing out problems. – pipe Jul 17 '17 at 11:08
• I do love a good pint of it: anchorbrewing.com/blog/wp-content/uploads/2014/02/… – Andy aka Jul 17 '17 at 13:13
• Weigh in the toxicity. IPA is quite harmless unless you drink a lot of it. Acetone has noxious fumes and is hard on your skin. – winny Jul 17 '17 at 14:32
• did anyone define "better" before the answer was accepted? I like Andy's IPA better. – Sunnyskyguy EE75 Jul 24 '17 at 22:00

Acetone being used to clean circuit boards can be problematic. The biggest issue that I found was that it leaves a residue in the board that still requires several other cleaning steps to get rid of including IPA and hot water.

Even IPA can leave a residue as it dries.

There is also the problem mentioned in the comments that the acetone can dissolve certain plastics to the great detriment of your electronics assembly. I've seen it eat away the plastic winding wraps on small transformers as an example.

• I've also seen acetone eat away at the casigns of connectors and trimmer pots – Joren Vaes Jul 17 '17 at 13:28
• Acetone is a definite no-no when cleaning PCB. It eats half your components and who knows what it does with the rest. Stay away from it at all times. – Mast Jul 18 '17 at 9:06

If you want real results to clean PCBs after rosin-based fluxes, you should use a specially-formulated solvent. Typically the solvents are based on IPA, but contain Toluene, Heptane, and Difluoroethane. Note - no acetone there.

• I need a more environmentally friendly option, and these solvents are not easily available in India. – NullCoderExists Jul 17 '17 at 22:46
• @NullCoderExists rubbing alcohol (IPA) works fine, especially the 99% type (faster dry, doesn't leave water behind.) – wbeaty Jul 17 '17 at 23:18
• @NullCoderExists, special chemicals are always hard to find for household use. You need to find a manufacturer for the flux-removing mixture. Some producers (like the Chemtronics) charge too much ($12-$25 per can). I took the cheapest one (\$6.99) from Fry's (Puretronics #6000 from T.E. Emerald), it works extremely well. – Ale..chenski Jul 18 '17 at 18:57

For rosin based flux I clean with IPA (93%) and then hot water with a detergent. Then dry. That is for one-of's or a small number of pcbs.

• De-ionized water, I assume and not tap? – Dirk Bruere Jul 17 '17 at 14:12
• @DirkBruere No just tap water. If it's a high impedance board (>=10 Meg ohm) then I just clean locally with acetone. – George Herold Jul 17 '17 at 14:16

Just adding to the answers because nobody's mentioned it yet - as well as melting plastic, acetone can strip the insulation off enameled (magnet) wires. So if you decide to use it be super careful not to spill any on motors or transformers!

Use methal spirit, it’s similar with IPA, the difference is methal spirit dry a bit slow. Sometimes people use it to clean windows

• Do you mean Methylated Spirits. (Methyl alcohol) – RoyC Nov 10 '18 at 13:21
• yes, that 's what I mean – Klng Lim Nov 11 '18 at 14:22
• Since beginning I used IPA to clean old & flux PCB, I felt a bit sticky on the board, when I change to use Methylated Spirit, no issue at all. – Klng Lim Nov 11 '18 at 14:33

Easily available solvent: I have used for years trichloroethane, cheap, effective, and not visible residue.

• Hi - Is it still easily available? Its use as a solvent was banned in the EU from 1 Oct 2000 by EU Ozone Regulation 2037/2000 (later superseded by EU Regulation 1005/2009, I think) due to it being an ozone depleter. (Other dates apply to counties outside the EU.) I agree it was a very good cleaner when we could use it, but unless you have a legitimate source now, and have found some rules that allow its use, then I don't see it being easily available now. :-( – SamGibson Sep 23 '17 at 21:54
• Hi Sam, I didn't pay attention and didn't know. Honestly the last time I bought is 4-5 years ago, at supermarket; I resumed doing pcbs only in the last year so 2 bottles are still there... I will keep an eye if I can find it. If not available any longer: IPA is expensive, why not using simple ethyl alcohol (C2H5OH)? the coloring agent maybe leaves residual, but then one can always buy that for food use, pure (and good taste :) ); I think it is easier to find than IPA, and - guessing - less expensive. – andrea Sep 24 '17 at 8:03
• Expensive? A couple of bucks for the good stuff (90%). – Robert Endl Nov 10 '17 at 15:30

Acid based would be Acetone.

ISO is more than enough for what I'd assume 99.99% of Engineering@Home Apps. to need. However that being said, they both work wonders on hardened, nasty, PCB, with flux everywhere. So if you want to rejuvenate your board, get acetone, less aqueous the better. Flammable, be careful like you would with a grenade. Use a gritted cloth and rubber gloves to slowly wipe away and immediately let dry your PCB. Circuitry should be ready for Re-Flux within 3-4 hrs if done properly. (Full-ATX Motherboard sized, etc.)

• Please use a more appropriate language – clabacchio Jul 18 '17 at 12:16
• look! it's trying to communicate! but seriously, this looks like a spam bot trying to talk – Makoto Sep 24 '17 at 13:58