Methylated spirit vs IPA - Page 1
Forum section: electronics / general

author: img
author_rank: Regular Contributor
timestamp: July 29, 2011, 06:36:10 pm
content: Please educate me: why is it that some people 'believe' in IMS and others in IPA? What's the difference? When do you use one, when do you use the other?Personally, I use IPA for everything, a friendly camera shop uses IMS only, but when I asked for an explanation all I got is a shocked stare.

author: Richard W.
author_rank: Regular Contributor
timestamp: July 29, 2011, 06:59:34 pm
content: methylated spirit leaves a white residue, IPA doesn't.

author: IanB
author_rank: Super Contributor
timestamp: July 29, 2011, 10:24:22 pm
content: They are different solvents with different dissolving properties. Methylated spirits is predominantly ethanol, whereas IPA is predominantly isopropyl alcohol. IPA is quite good at cleaning greasy marks, fingerprints, solder flux etc, from glass, circuit boards, tape heads and optics. It evaporates more slowly than meths. The IPA in my cleaning supplies is >99.9% pure and it should evaporate with no residue.Pure anhydrous alcohol >99.9% would also be a clean solvent except you can't obtain it outside of a chemical laboratory and in any case it does not dissolve flux or grease very well. Methylated spirits is ethanol mixed with some methanol to make it poisonous, a bitter substance to make it undrinkable, and a purple dye to warn you what it is. It should be a fairly clean solvent but the dye and bitter substance could be left behind as a residue when it evaporates.In the USA methylated spirits is rarely found. What you find instead is denatured alcohol, which is ethanol mixed with some gasoline and other adulterants to make it undrinkable. I really wouldn't want to use this as a high purity solvent, but in any case it doesn't dissolve solder flux so it's of little use for cleaning circuit boards.For optics, methanol is often chosen as a cleaning fluid. This you may find from an optics supplier like a camera shop or a telescope shop. However methanol is poisonous so it should be used with care. Wear rubber gloves, use it in a ventilated area, don't get it on your skin and don't breathe the fumes. If you get 99.9% pure methanol it is a very clean solvent that will leave behind no residue at all and will evaporate quickly.

author: RCMR
author_rank: Frequent Contributor
timestamp: July 30, 2011, 12:42:59 am
content: Quote from: IanB on July 29, 2011, 10:24:22 pmDon't tell this to the millions of RC model fliers who regularly find themselves bathed in methanol.It is true that methanol is highly toxic but you've somewhat overstated the dangers.The skin provides a good barrier against absorption and the fumes are more dangerous due to their wide stoichiometric ratio than because of any toxic effect on the body -- at least in the concentration levels you're likely to find when using a small bottle of the stuff in a room larger than your toilet.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 30, 2011, 01:14:47 am
content: Wow nice descriptions IanBIn Greece we have isopropyl alcohol but is extremely expensive but very high quality.The lesser expensive alcohol ( for general use ) it is painted blue, and it is alcohol mixed with water.About cleaning lens I got one cleaning kit from Carl Zeiss,it has a bottle with some fluid, but it does not evaporate that fast.The set includes 10 moistened wipes, those does miracles,but they are for one use only.https://photo-shop.zeiss.com/epages/cz.sf/en_GB/?ObjectPath=/Shops/CZ/Products/1216-071

author: IanB
author_rank: Super Contributor
timestamp: July 30, 2011, 01:33:16 am
content: Quote from: RCMR on July 30, 2011, 12:42:59 amIt never hurts to emphasize the dangers of something. On matters of fact I need to point out to you that skin is not a barrier to methanol absorption and this is one of the primary ways methanol can enter the body. Also note there are many toxic effects of methanol short of death to be wary of. Just because you haven't died doesn't mean you are not in danger of injury.Honestly, splashing methanol over your skin with wild abandon is foolish. It's a risk you really don't need to take.See, for instance:http://avogadro.chem.iastate.edu/MSDS/methanol.htm

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: July 30, 2011, 02:13:26 am
content: I'm a fan of Acetone. It has a much higher vapour pressure, so it vapourises quicker. And they are great for removing toner.

author: IanB
author_rank: Super Contributor
timestamp: July 30, 2011, 02:19:18 am
content: The trouble with acetone is it removes anything and everything. Often it will remove parts of the thing you are trying to clean. Acetone is the mutually assured destruction of cleaning solvents...nothing useful may be left after you use it.

author: img
author_rank: Regular Contributor
timestamp: July 30, 2011, 06:27:02 am
content: Thank you all for the explanations (IanB, you're my hero).I'll stick with my trusty IPA from now on.

author: vk6zgo
author_rank: Super Contributor
timestamp: July 30, 2011, 07:46:24 am
content: The "white residue" problem with Methylated Spirits tends to be overstated by many people,as a lot of the residue you see on PCBs is simply dissolved flux.In the case of repaired PCBs,any residue does a lot less harm than the crud commonly found on the boards due to their operating environment."Metho" in Australia does not contain dye,& the amount of Methanol included is quite small,to the point that the only health warning on the label is "Do not drink".Many commonly used domestic cleaners are much nastier,as is Unleaded Petrol (Gasoline).In earlier times,we used such delightful substances as Carbon Tetrachloride!VK6ZGO

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: July 30, 2011, 09:15:03 am
content: Quote from: IanB on July 30, 2011, 02:19:18 amAnd that's why it's awesome... but yeah, choose your surface carefully.Quote from: vk6zgo on July 30, 2011, 07:46:24 amThey are not too bad, the one I got from Bunnings is 95% pure.

author: Unknown
author_rank: Unknown
timestamp: July 30, 2011, 01:25:12 pm
content: Quote from: IanB on July 30, 2011, 02:19:18 amIt doesn't remove everything, but it dissolves many kinds of plastics. I used once it to clean some glue from a calculator. The glue was gone, but it also damaged the plastic case, so the end result was just as ugly. Metals, ceramics, glass and some types of plastics are just fine. In optics, some filters and mirrors are also cleaned with acetone, although you should check with the manufacturer whether the coating will tolerate it.

author: vk6zgo
author_rank: Super Contributor
timestamp: July 30, 2011, 02:28:27 pm
content: Quote from: AntiProtonBoy on July 30, 2011, 09:15:03 amYeah! that's where I got mine!Nail polish remover is mostly acetone.At my last work we had a big switchmode power supply blow up,& before we could replace the PCB we had to remove a lot of brown "scunge"from it.We tried everything to no avail,so eventually I brought some of my wife's Nail polish remover to work.A couple of drops on a rag,& the disgusting mess was gone.It is also good for removing Polymer fallout from car windscreens---but be careful!VK6ZGO

author: FreeThinker
author_rank: Frequent Contributor
timestamp: July 30, 2011, 03:55:12 pm
content: Quote from: vk6zgo on July 30, 2011, 07:46:24 amWhoa! Carbon Tet, I can still smell it now. We used to use it as a general degreaser for motors etc. in the maintenance workshop and had degreasing pots in the heat treat department which were 5 to 6 metres deep, 1.5 metres diameter with heater coils in the bottom covered by 50 or so gallons of Carbon Tet. When heated you could see a white mist in the bottom of the tank as the vapour re condensed. Really healthy!!

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 30, 2011, 03:57:01 pm
content: Quote from: IanB on July 29, 2011, 10:24:22 pmagain, your teacher taught you well. the sound makes it the same class as viper sting. recommends youngs to stay at home. "dont open the unit, no user repairable inside". i bathed with spirit, thinner (what is thinner constitutes anyway?), and sometime... fiberglass resin.

author: Gall
author_rank: Frequent Contributor
timestamp: July 30, 2011, 04:26:29 pm
content: In fact, methanol DOES absorb through the skin. It is unlikely to get poisoned by an occasional splash, just do not put your hands intentionally into methanol bath.Methanol is not so toxic as some other organic solvents as long as it isn't ingested. The only thing that's really dangerous is that methanol's toxic effects are delayed (several hours after exposure) and can be permanent. So there's a chance to get poisoned without noticing it until it's too late.A good antidote is ethanol. If you suspect you're in danger of methanol poisonong - just go to the bar and get drunk!

author: Zero999
author_rank: Super Contributor
timestamp: July 30, 2011, 04:44:23 pm
content: Methylated spirit doesn't contain a massive concentration of methanol and is certainly not enough to cause poisoning by occasional skin contact. It's a good idea to wear gloves when using methylated sprint because it dissolves natural skin oils which can cause dermatitis, like any harsh organic solvent. It's a good idea to be in a well ventilated area whilst using methylated spirit because it smells horrible and can cause headaches, just like most other organic solvents.I'm not saying you should wear thick rubber gloves and only use methylated spirit in a fume cupboard, just don't use it in confined spaces, keep the windows open (if possible and practical) and avoid getting it on your skin.

author: IanB
author_rank: Super Contributor
timestamp: July 30, 2011, 04:57:48 pm
content: Quote from: Hero999 on July 30, 2011, 04:44:23 pmNo one is saying methylated spirit is particularly toxic (unless you drink it), but pure methanol as mentioned above is a different story. Pure methanol certainly merits caution in handling. It may not be "very" poisonous, but you certainly shouldn't splash it around like cologne.Incidentally a danger not mentioned yet with both methylated spirits and methanol is flame and sources of ignition. Alcohol fumes will ignite quite readily and when alcohol does burn the flame can be almost invisible and therefore not noticed. People have been injured by pouring alcohol on or near a flame causing a big fireball, especially when topping up an alcohol burner that is still alight.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 30, 2011, 05:04:50 pm
content: Quote from: Hero999 on July 30, 2011, 04:44:23 pmwell tonight i just bought 1 new bottle with big "spirit" written on it.got no smell!, but evaporates quickly and i know its darn flammable. maybe an immitation or only contain <1% methanol?

author: IanB
author_rank: Super Contributor
timestamp: July 30, 2011, 05:28:10 pm
content: Quote from: Mechatrommer on July 30, 2011, 05:04:50 pm"spirit" is not sufficient to say what it is. It must surely say on the label at the back what the bottle contains?Note that methylated spirits is alcohol and smells like, well, alcohol. If you don't know what alcohol smells like, open a bottle of vodka and have a sniff.It is possible that what you have is this:http://en.wikipedia.org/wiki/Mineral_spiritsThat stuff is a good cleaner and degreaser, but it might damage plastic parts or painted surfaces.

author: Zero999
author_rank: Super Contributor
timestamp: July 30, 2011, 06:16:27 pm
content: Methylated spirits have a more bitter, altogether more noxious smell than vodka which could be due to the addition of methanol or possibly other chemicals to put people off drinking it.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 30, 2011, 06:57:32 pm
content: no label on content at the back. i guess it read as "elcheapo". something that can damage plastic, painted surface, or permanent marker, i call it as "thinner", and it smells like you keep your urine for one week in a bottle and smell it. not exactly, but some element of smell is similar. i guess what i've used so far is consumer grade (diluted) spirit.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 30, 2011, 07:06:31 pm
content: ok ok i got the content for "my thinner" toluene 60%, ketone 20%, other solvent 20%. this is the best pcb/flux cleaner i have so far from local, but it still leave slight residue, waterish like that difficult to evaporate, i need to use a blower to get rid of it. maybe i'm talking different vocabulary here, but hey its not my fault, its the manufacturer wrote on it.

author: IanB
author_rank: Super Contributor
timestamp: July 30, 2011, 07:20:23 pm
content: Quote from: Mechatrommer on July 30, 2011, 07:06:31 pmPerfect, what you have there is general purpose degreasing solvent. You might use it for cleaning bicycle chains, car engine parts, paint brushes, stuff like that. I wouldn't recommend it for circuit boards but you could use it if it is all you have.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 30, 2011, 07:26:55 pm
content: Quote from: img on July 29, 2011, 06:36:10 pmok ok maybe i forgot the intro. IMS is "Methylated spirit" what is "I"? IPA, well, from wiki its...International Phonetic AlphabetInternational Phonetic AssociationIndia Pale AleInternational Police Associationi dont think those fit the discussion here?

author: Bored@Work
author_rank: Super Contributor
timestamp: July 30, 2011, 07:30:28 pm
content: Quote from: IanB on July 30, 2011, 04:57:48 pmPeople do that even when there is a visible flame, i.e. ethanol. We had e series of severe accidents last Christmas. Table "bio fireplaces" became popular, because they make such a nice mood lighting and there was an influx of cheap table bio fireplaces from China. These "bio fireplaces" are ethanol burners.Some people managed to wipe the burner from the table, spilling burning ethanol around. Others bought cheap Chinese stuff and then had so learn the burner got so hot it burned through the table. But the most common way to kill or almost kill themselves and to burn down the house was trying to refill a burner while it was still burning.

author: oPossum
author_rank: Super Contributor
timestamp: July 30, 2011, 07:31:13 pm
content: IsopropylAlcohol

author: Kozmyk
author_rank: Regular Contributor
timestamp: July 31, 2011, 12:03:48 am
content: My dad used to rub Meths into his hands to harden the skin before gardening.My favourite general purpose solvent is Isopropyl Alcohol (99.9% preferred to the 70%with water).I find IPA shifts most flux residues with a little rubbing; most importantly it doesn't attack the soldermask or screenprinting on PCBs.It also insinuates itself under hot glue so it's great for removing that stuff.I first used it in recording studios to clean the tape heads without attacking the resins holding the laminations together.I keep some Acetone handy which is great on metals but will melt a lot of plastics or at least make their surfaces sticky.Colclene used to be some trichloroethylene variant but I think it's moved on to some more eco-friendly formulation now. Very light solvent leaves no trace.Servisol 10 is my switch cleaner, good cleaning properties with a little lubricant residue.Good old WD40, Castrol DWF and other petroleum based is fine for mechanical work but can make the inside of a potentiometer go all gooey.Of course most plastics meant for automobile applications should tolerate WD40 as part of their fuel resistant properties.I'm just beginning to learn that you can thin epoxy resin with both IPA and acetone.

author: Gall
author_rank: Frequent Contributor
timestamp: August 01, 2011, 07:22:19 am
content: The biggest difference between either pure or methilated ethanol and IPA is its activity.Ethanol (pure or meths) tends to dissolve some resins, varnishes and even plastics. IPA doesn't.But IPA stinks.

author: ejeffrey
author_rank: Super Contributor
timestamp: August 01, 2011, 09:26:12 am
content: Generally my order of choice for solvents is water, IPA, acetone, methanol. Water is too often overlooked. If water won't damage your device, it is usually the best thing to start with. It is very polar, so it dissolves a lot of things the organic solvents are not so good at. If you use DI water and have no pockets that can trap water, it is ok to let it air dry. Gentle heating will speed the process. Otherwise, follow with IPA and blow off with compressed air. This will do a pretty good job of displacing the water so it doesn't leave its dissolved salts on the board. Acetone is the heavy duty basic solvent, but is the most likely to damage your device. Methanol is the most heavy duty alcohol, and is good to use when IPA isn't strong enough and you can't use acetone. Both methanol and acetone evaporate very quickly, which can be annoying -- if it evaporates too fast it will just redeposit the crud it dissolved. I don't usually use ethanol because it can be hard to find pure.Mixed solvent cocktails like paint thinners and grease removers can be very effective, but they are not very clean themselves. You may need to follow with water and/or alcohol to get a really clean surface. Another factor here is that lots of devices specify solvent resistance for alcohols and acetone, so you can be more confident it won't do any damage. Other solvents may be more of a gamble.

author: Zero999
author_rank: Super Contributor
timestamp: August 01, 2011, 08:22:12 pm
content: Quote from: Mechatrommer on July 30, 2011, 07:06:31 pmIt may be a great solvent but it's toxic, toluene can cause blindness, brain damage and mental retardation. Your mixture probably also contains benzene which is a deadly carcinogen, much worse than any of the ingredients listed. Use only in a well ventilated area, wear gloves and obviously don't drink it.

author: IanB
author_rank: Super Contributor
timestamp: August 01, 2011, 08:25:40 pm
content: Quote from: Hero999 on August 01, 2011, 08:22:12 pmJust like unleaded petrol (gasoline) then?(When they took the lead out of petrol they had to put in other things like toluene and benzene to keep the octane rating up.)

author: ElektroQuark
author_rank: Unknown
timestamp: August 02, 2011, 06:44:53 am
content: Toluene mixes sometimes also have xylene. They make a good paint thinner/remover but are very toxic. A well ventilated area and protection goggles and gloves are highly recommended.

author: IanB
author_rank: Super Contributor
timestamp: August 13, 2011, 07:13:08 pm
content: I have just discovered that while IPA when used with a rag will nicely clean flux spills off my work bench, IPA when used with a horse hair brush and a gentle scrubbing actionwill notremove flux residues from a PCB. I guess I'm off to the hardware store to find some acetone...

author: Kozmyk
author_rank: Regular Contributor
timestamp: August 14, 2011, 01:37:07 pm
content: Quote from: IanB on August 13, 2011, 07:13:08 pmIPA on a cotton bud will shift post soldering flux residue from a PCB with bit of scrubbing. You need more friction than a brush can provide to get it going.Depending on what flux you have YMMV.Be prepared for the acetone to remove more than you bargained for.

author: IanB
author_rank: Super Contributor
timestamp: August 14, 2011, 02:19:17 pm
content: Quote from: Kozmyk on August 14, 2011, 01:37:07 pmI used a 50/50 mixture of acetone and IPA with decent results. I was cleaning the back of a through-hole board and I didn't let the solvent mix get on the component side of the board.