Alcohol versus Lighter fluid for cleaning? - Page 1
Forum section: electronics / general

author: kalel
author_rank: Frequent Contributor
timestamp: November 06, 2017, 03:45:54 am
content: I've seen in the "Electronics repair school" channel Petrol often used for two purposes.1 - Cleaning2 - Detecting shorts by applying some petrol, applying power to a circuit, and then observing if any part dries faster than others (seems to work for him)Being an amateur, I'm wondering about whether or not alcohol or petrol (lighter fluid) is better for cleaning circuit boards from things such as dirt, dust, flux residue. Should I have both, or is one enough.Considering concentrations, I understand for both liquids that they should be as concentrated/clean as possible.

author: rdl
author_rank: Super Contributor
timestamp: November 06, 2017, 04:01:55 am
content: Alcohols and petroleum distillates are two very different types of solvent. What one type is good for, the other may be useless. Even among each type there are considerable differences.

author: rdl
author_rank: Super Contributor
timestamp: November 06, 2017, 06:00:07 am
content: You could mix them together. You'd have something that's about as good as you can get without much chance of damaging plastics. Of the commonly available alcohols, I'd choose ethanol, with isopropanol (IPA) as second choice. Most electronic parts are fairly solvent resistant and will tolerate stronger stuff such as esters and ketones, but testing first is recommended. A blend such as "lacquer thinner" is useful to have around.

author: Mjolinor
author_rank: Frequent Contributor
timestamp: November 06, 2017, 06:02:17 am
content: IPA needs to be better than 99.6%. If you have any water in it it will dissolve a lot more stuff for some reason that I do not know.

author: helius
author_rank: Super Contributor
timestamp: November 06, 2017, 06:40:28 am
content: Many electronic board cleaners use a mixture of alcohols and alkanes, sometimes with ketones also. For example,MG 4050Acontains isopropyl alcohol, isomers of n-hexane, ethanol, and ethyl acetate. There are similar products from Chemtronics (ES1035 Flux-Off, Rosin).Petrol/gasoline is a blend of primarily alkanes, mostly of higher weight than hexane. Something like camp fuel or "white gas" would be suitable for cleaning non-ionic residues or as an ingredient in a flux remover mixture. The problem is that vehicle fuel contains other chemicals, of unknown reactivity in electronics. Some are toxic.

author: amyk
author_rank: Super Contributor
timestamp: November 06, 2017, 06:46:25 am
content: Maybe it's a vocabulary issue, but I wouldn't use petrol (the motor fuel) for cleaning electronics. Pure octane might be OK, but it's also extremely flammable.

author: rdl
author_rank: Super Contributor
timestamp: November 06, 2017, 07:08:16 am
content: Anytime discussion about solvents occur there is always much confusion because of using common names, which often differ wildly from one part of the world to another. In my replies I did assume the "petrol (lighter fluid)" mentioned in the first post to be some kind of light aliphaticnaptha. Hopefully that was what was meant.

author: IanB
author_rank: Super Contributor
timestamp: November 06, 2017, 07:23:22 am
content: Yes, there is the (non-butane) kind of lighter fluid, which is a light petroleum spirit. A similar substance can be purchased as a fuel for camping stoves and lamps. There is also kerosene, less volatile and much safer, also used as a camping stove fuel. These solvents would be very good for removing tar, oil and grease, but not necessarily good as general purpose cleaners.I think alcohol remains better as a gentle, safe cleaner for most purposes.

author: kalel
author_rank: Frequent Contributor
timestamp: November 06, 2017, 07:57:55 am
content: I was confused myself by the name petrol, but I do mean the type of liquid you can find as lighter fuel, but not butane.For instance, the guy from "Electronics repair school" channel likes to use it often to clean boards:https://youtu.be/VxpSAAjNhd8(Go to time 301)In the example above, he's cleaning some wine.

author: IanB
author_rank: Super Contributor
timestamp: November 06, 2017, 08:01:51 am
content: This is an area where you can get the best answers by testing for yourself. It is always helpful to keep a variety of solvents and cleaners on hand. Try them out and choose the ones that work best for the job at hand.

author: Cubdriver
author_rank: Unknown
timestamp: November 06, 2017, 08:58:54 am
content: Quote from: Mjolinor on November 06, 2017, 06:02:17 amIPA/water solution dissolves more than pure IPA because the water contained in the mix also acts as a solvent. Some things that won't dissolve in pure alcohol will dissolve in the water, and things that the water won't touch dissolve in the alcohol. Thus, the combination will clean more than either will by itself.-Pat

author: rbm
author_rank: Regular Contributor
timestamp: November 06, 2017, 09:13:21 am
content: Watch repair involves cleaning very fine mechanical parts to remove oil residue and other contaminants. Lighter fluid, aka naphtha, is recommended followed by a rinse in 99% pure IPA. The reason naphtha is used is because pure alcohol will dissolve the shellac used to secure pallet stones to the escape lever if left for soaking but naptha will not. The subsequent IPA rinse removes any residue that may be left from the naphtha but it does not remain long enough to affect the shellac.If these ideas are applied to electronics cleaning, there probably is no reason that naptha cannot be used to remove the same type of oily contaminants that plague watches.Personally, I do all my PCB cleaning with IPA, Kimwipes and a brush, followed by a blow dry to evaporate any remaining alcohol.

author: Ian.M
author_rank: Super Contributor
timestamp: November 06, 2017, 09:41:22 am
content: We've had this discussion fairly recently:https://www.eevblog.com/forum/repair/cleaning-wd-40-of-contacts/msg1328380/#msg1328380TLDR: IPA isn't very good at removing longer chain oily residues. With vigorous scrubbing, its somewhat effective as it reduces the tendency of oil droplets to re-adhere. Lighter fuel grade light Naptha is effective for oil and wax removal and is compatible with more plastics than many other readily available non-specialist alternatives.If you use an oily paste flux, or have contaminated your board with WD40 or similar, Naptha can probably help. However, for most board cleaning applications which do not involve removing oil or wax contamination, IPA is more effective.