Author Topic: Everyone's Favorite Solvent?  (Read 12812 times)

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Offline rdl

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Re: Everyone's Favorite Solvent?
« Reply #25 on: February 28, 2014, 05:11:25 pm »
In general, ethanol is a better solvent than isopropanol, but not as good as methanol for some things. I wonder if the reason IPA seems to be used more in electronics has something to do with the solubility of rosin flux.

Ethanol is probably a little safer to use, after all people have been drinking it for thousands of years, whereas methanol is classified as a poison and will cause blindness or death if consumed and isopropanol will make you extremely sick at best. Warning, do not drink denatured ethanol, they put a small amount of other solvents in it to make it undrinkable, otherwise it would have to be taxed as liquor.

The plastics used for electronic parts are almost always "thermoset" types such as nylon, polypropylene, polyethylene, etc. These are not affected by solvents much, if at all. Others like ABS and polystyrene however, are thermoplastic and will dissolve in the active solvents such as acetone, MEK, etc.
 

Offline JoeyP

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Re: Everyone's Favorite Solvent?
« Reply #26 on: February 28, 2014, 06:12:05 pm »
For cleaning rosin flux off of PCBs I always default to acetone. For anything else, I progress through these until something happens:

1. Water (cleans organic compounds like coffee which don't respond as well to chemical solvents)
2. Methanol
3. Acetone
4. Mineral spirits
5. MEK
6. Xylene (about as strong as MEK, but some things respond better to it)
7. Sand blasting
8. Torch
9. Hammer
 

Offline M0BSW

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Re: Everyone's Favorite Solvent?
« Reply #27 on: February 28, 2014, 06:18:11 pm »
I don't mind any of them, as the law is over here in the UK, your asked if your 18 years old, when you try and buy them, and at almost 60, that makes my day when I'm asked.
no one would or will tell me how to delete this account
 

Offline 6E5

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Re: Everyone's Favorite Solvent?
« Reply #28 on: February 28, 2014, 06:21:56 pm »
Hi,

Sorry, I buy it from a small local store who's friends with the family. But yes, from home depot its usually $20 a gallon.


I buy everything but the DeOxit in 5 gallon tanks for $20.
Where are you finding it that cheap?

I'm used to seeing 1 gal containers for ~20 (denatured alcohol), and cheapest price on a 5 gal ~$43 FWIW, so a cheaper source/s would be extremely helpful. Could also use sources on cheaper IPA and maybe some MEK ($92 for 5 gal).
 

Online David Hess

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Re: Everyone's Favorite Solvent?
« Reply #29 on: February 28, 2014, 06:29:43 pm »
In general, ethanol is a better solvent than isopropanol, but not as good as methanol for some things. I wonder if the reason IPA seems to be used more in electronics has something to do with the solubility of rosin flux.

I have noticed before that some rosin thinners use IPA but in cleaning applications, I suspect isopropyl alcohol is used because of easy availability and lack of tax or denaturing issues.  If it were not for the BATFE, I suspect ethanol would be the preferred choice between the two.
 

Offline nanofrog

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Re: Everyone's Favorite Solvent?
« Reply #30 on: February 28, 2014, 07:34:15 pm »
nylon, polypropylene, polyethylene
These are all thermoplastics as well, not thermosets. Take nylon for example (6 or 6,6). Comes in pellets for injection molding, and though it's resistant to most common solvents, it will dissolve in resorcinol for example (Benzene-1,3-diol).

Sorry, I buy it from a small local store who's friends with the family. But yes, from home depot its usually $20 a gallon.
Wish I had contacts like that.  ;)
 

Offline N2IXK

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Re: Everyone's Favorite Solvent?
« Reply #31 on: February 28, 2014, 07:34:53 pm »
The plastics used for electronic parts are almost always "thermoset" types such as nylon, polypropylene, polyethylene, etc. These are not affected by solvents much, if at all. Others like ABS and polystyrene however, are thermoplastic and will dissolve in the active solvents such as acetone, MEK, etc.

The distinction between thermoplastics and thermoset plastics has NOTHING to do with solvent compatibility. Thermoset polymers will not remelt when heated.  Bakelite is the classic example of a thermoset resin. Other examples are epoxies, melamine, and polyurethanes.

Nylon, polypropylene, and polyethylene are all thermoplastics.
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Offline gibbled

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Re: Everyone's Favorite Solvent?
« Reply #32 on: February 28, 2014, 07:59:39 pm »
Methylene chloride is my solvent of last resort.   Available by the gallon at plastic fabricator shops.

 

Offline rdl

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Re: Everyone's Favorite Solvent?
« Reply #33 on: February 28, 2014, 08:09:41 pm »
Yeah, I was kind of in a hurry. I meant to say something like "types that act more like thermoset", but I got in a hurry because I was late to an appointment. It has more to do with molecular weight and crystallinity, but I didn't want to get that detailed. At the coatings companies I've worked at, we'd to use a lot of polypropylene cups and beakers and such. We'd wash them with MEK or acetone, they could withstand weeks of soaking without much degradation. Whereas something like polystyrene will just melt almost instantly in acetone.
 

Offline JoeyP

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Re: Everyone's Favorite Solvent?
« Reply #34 on: February 28, 2014, 09:01:06 pm »
Methylene chloride is my solvent of last resort.   Available by the gallon at plastic fabricator shops.

Methylene chloride (AKA Dichloromethane) is one I've never tried. What is it particularly good at as compared to the others? Does it for example dissolve something like epoxy quickly?

In looking it up, I came across this site which has properties of a very wide range of solvents (and apparently online ordering of same):

http://www.sigmaaldrich.com/chemistry/solvents/dichloromethane-center.html
 

Offline robrenz

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Re: Everyone's Favorite Solvent?
« Reply #35 on: February 28, 2014, 09:09:27 pm »
I have always thought of methylene dichloride or trichloride as a solvent glue for acrylic/plexiglass.

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Re: Everyone's Favorite Solvent?
« Reply #36 on: February 28, 2014, 09:24:06 pm »
Nothing dissolves epoxy (though fuming nitric acid burns it away pretty reasonably...along with everything else..), but DCM is one of the few solvents that softens it, IIRC.

Speaking of solvent welding, THF (tetrahydrofuran) is a primary constituent of PVC cement.

Oh, for something around IPA or acetone, but a little heavier, one could try ethyl acetate (typically a component of nail polish remover).

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Offline gibbled

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Re: Re: Everyone's Favorite Solvent?
« Reply #37 on: February 28, 2014, 10:00:00 pm »
Methylene chloride is my solvent of last resort.   Available by the gallon at plastic fabricator shops.

Methylene chloride (AKA Dichloromethane) is one I've never tried. What is it particularly good at as compared to the others? Does it for example dissolve something like epoxy quickly?

In looking it up, I came across this site which has properties of a very wide range of solvents (and apparently online ordering of same):

http://www.sigmaaldrich.com/chemistry/solvents/dichloromethane-center.html

It is the active ingredient in the good paint strippers but doesn't have the gelling agents and wax.   A little in a sealed mason jar overnight with smps transformers and they come apart easily.
A long soak softens many potting compounds too. (although it often softens the potted components :-\)

Also handy to rapidly solvent weld some plastics.



 

 

Offline Zepnat

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Re: Everyone's Favorite Solvent?
« Reply #38 on: February 28, 2014, 11:43:03 pm »
Although not exactly a solvent my favourite liquid in a can is plain old gas lighter refill from discount stores.

It is, I believe, similar to butane/propane or isobutane mix that is used in Air Duster cans, in the UK at least not sure about other parts of the world.

With a nozzle and small tube it works great for only 99p, against the ~£5 cost of proper air duster its a bargain.
Turned upside down its also useful for freezing stuff too  >:D

But people get a bit uptight about it, spray Air Duster all over the place and although Highly Flammable is prominently written in red no ones minds, grab a can of 'lighter fluid' with a tube on it and people are like 'WE'RE ALL GONNA DIE'!
 

Offline N2IXK

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Re: Everyone's Favorite Solvent?
« Reply #39 on: March 01, 2014, 01:57:00 am »
Most of the "canned air" products I have seen here in the states were non flammable HFC-based, not hydrocarbon.  Is the use of hydrocarbons a recent development related to ODP?  I'm lucky enough to have shop air, so haven''t used one of the canned products in years.

DCM is good stuff for reverse engineering applications. Will soften most epoxy potting compounds with long term exposure/submersion. I have fond memories of using the stuff to depot/ reverse engineer cable TV descrambler circuits back in my high school days.  :) And as mentioned, great stuff for solvent welding styrene, acrylic or polycarbonate. Nasty fumes, though (and probable liver toxin/suspect carcinogen), so use in sealed container, or outdoors if you don't have access to a fume hood.







« Last Edit: March 01, 2014, 02:02:50 am by N2IXK »
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Offline vk6zgo

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Re: Everyone's Favorite Solvent?
« Reply #40 on: March 01, 2014, 02:11:41 am »
Nothing dissolves epoxy (though fuming nitric acid burns it away pretty reasonably...along with everything else..), but DCM is one of the few solvents that softens it, IIRC.

Speaking of solvent welding, THF (tetrahydrofuran) is a primary constituent of PVC cement.

Oh, for something around IPA or acetone, but a little heavier, one could try ethyl acetate (typically a component of nail polish remover).

Tim

We had a Switch mode power supply self-destruct at work,so ordered a replacement from the equipment manufacturer in the PRC.
It duly arrived,mounted on a different sized heat sink which wouldn't fit our gear,so we had to swap the guts over to the old one.

There was a layer of black crud across the old heatsink,witha very large blob of melted gunk right in the middle.
I tried  denatured alcohol (Metho in Oz talk),Turps, "White Spirit"& Eucalyptus oil---nothing would budge it.

I borrowed my wife's Nail Polish remover---about a teaspoonful on a cloth removed the stuff easily.
 

Offline rstoer

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Re: Everyone's Favorite Solvent?
« Reply #41 on: March 01, 2014, 06:16:18 pm »
I can't get away from methanol. I used it for over twenty years when I had my electronics repair business. When I started in 1969 I bought it by the gallon at the local hardware store. By the time I sold out in 1992 we had to special order it from a lab supply for big $ (at least compared to the hardware store).
I've tried everything else since. The substitutes either don't do the job as well or they eat plastics. Now that I'm back into electronics (mostly as a hobby), I got myself a liter of it (through Amazon) and it works as well as I remember.
They say it doesn't take much of it to kill you but after all these years I'm still here. Probably isopropyl is the closest in results and it's much safer, but once you've used the real thing...

I have a litter of methanol for optics stuff, but I rarely use it out of fear it will absorb though my skin (really, its more of a laziness to get up and find a pair of gloves). Did you always use gloves?
No, I don't wear gloves. I know I should but before anyone knew you were supposed to I had been using it for decades without. No harm came to me (that I'm aware of) so I can't be bothered to start now.

In the US it was not until the 80s that restrictions began to be put on it. Before that all that was said about methanol was if you drank it you'd go blind or die. Now you practically need a hazmat suit to handle it. I would not suggest anyone not wear gloves when using it but if you're unhappy with your present cleaner of choice, it may be worth it to 'suit up' (or at least 'glove up') and give methanol a try. It's much gentler with plastics than ethanol and it cleans better than isopropyl.
 

Offline PedroDaGr8

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Re: Everyone's Favorite Solvent?
« Reply #42 on: March 01, 2014, 10:44:21 pm »
Yay my world. As a chemist I have a world of solvents at my disposal. I often use solvents like chloroform abd methanol liters at a time. Methanol isn't that bad. For bulk toxicity the rule of thumb was half as drunk twice as dead in comparison to ethanol. So it's twice as toxic but had half the energizing effects. The bigger issue is it's potential carcinogenicity. Our body, as well as the bacteria in our gut, naturally produces small amounts of methanol as byproducts of metabolism. That being said wear gloves if you have them. Plus be very aware of open flames. Pure methanol burns with a faint blue flame it can be very very hard to see.

Now for my favorite solvents:
1) chloroform/methylene chloride
2) alcohols (methanol, isopropanol, 1-butanol)
3) Non-polars (xylene, toluene, benzene, hexanes)
4)DMSO/DMF (great for polar materials that aren't handled by the above)
5) ethers
6) ketones and acetates

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Offline CaptnYellowShirt

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Re: Everyone's Favorite Solvent?
« Reply #43 on: March 02, 2014, 04:43:20 am »
In the US it was not until the 80s that restrictions began to be put on it. Before that all that was said about methanol was if you drank it you'd go blind or die. Now you practically need a hazmat suit to handle it. I would not suggest anyone not wear gloves when using it but if you're unhappy with your present cleaner of choice, it may be worth it to 'suit up' (or at least 'glove up') and give methanol a try. It's much gentler with plastics than ethanol and it cleans better than isopropyl.

I had worked worked with Hg manometers for years before the health and safety people got wind of it. From their response, you'd think have 2 oz of this stuff covered by water in a glass tube was like forcing orphans to refine Plutonium with their bare hands.
 

Online T3sl4co1l

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Re: Everyone's Favorite Solvent?
« Reply #44 on: March 02, 2014, 06:23:47 am »
Heh...

Mercury is given a lot worse rep than it deserves.  AFAIK, metallic mercury isn't really harmful, until extended exposure is had.  The *real* nasties are organomercury compounds, like dimethylmercury (a recent case being several years ago, a researcher working with the stuff got only a drop on her hand -- it diffused through two layers of gloves -- and succumbed to the symptoms several months later :o ).

On topic... mercury is a good solvent for many metals, including gold, silver, copper, tin, aluminum, etc.  At STP, it evaporates...rather slowly to say the least, especially compared to the organic solvents listed in this thread.  So it usually requires heating to achieve the same effect (ideally, by distilling it off under vacuum).  The first samples of calcium, magnesium, etc. metals were obtained in this way (by forming an amalgam, then distilling the mercury off).

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Offline SeanB

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Re: Everyone's Favorite Solvent?
« Reply #45 on: March 02, 2014, 07:37:39 am »
Still have a kilo of mercury around in a bottle, wrapped in a cloth and packed in a tin outer just in case. You need to take a big block of Aluminium and drill a small dent into the top of a smooth block, place a drop of mercury there and scratch through it to expose the metal to the mercury and leave it in a glass dish in a warm spot for a month. It vanishes leaving the mercury behind, and a dish full of oxide flowers.
 

Offline JoeyP

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Re: Everyone's Favorite Solvent?
« Reply #46 on: March 03, 2014, 06:26:19 pm »
I can't get away from methanol. I used it for over twenty years when I had my electronics repair business. When I started in 1969 I bought it by the gallon at the local hardware store. By the time I sold out in 1992 we had to special order it from a lab supply for big $ (at least compared to the hardware store).

Your comment got me wondering about methanol. I've been using "Denatured Alcohol" for a long time, and thought it was mostly methanol. I buy it from Home Depot by the gallon. Doesn't say on the can just what it is, but does say it contains methanol, so I thought it was mostly methanol. Just looked it up, and found that it's about 50% methanol, 50% ethanol and a little methyl isobutyl ketone.

As far as exposure, I've been soaked up to my elbows in this stuff many times over decades, with no known effects so far (other than temporarily very dry skin) - I'm extremely healthy, and no spring chicken. I just had a look at the MSDS, and it appears that acute exposure (like drinking the stuff) can kill you or cause blindness, but typical skin contact or inhalation is likely to only cause various temporary forms of irritation like nausea or headache.
 

Offline CaptnYellowShirt

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Re: Everyone's Favorite Solvent?
« Reply #47 on: March 03, 2014, 06:45:37 pm »
I can't get away from methanol. I used it for over twenty years when I had my electronics repair business. When I started in 1969 I bought it by the gallon at the local hardware store. By the time I sold out in 1992 we had to special order it from a lab supply for big $ (at least compared to the hardware store).

Your comment got me wondering about methanol. I've been using "Denatured Alcohol" for a long time, and thought it was mostly methanol. I buy it from Home Depot by the gallon. Doesn't say on the can just what it is, but does say it contains methanol, so I thought it was mostly methanol. Just looked it up, and found that it's about 50% methanol, 50% ethanol and a little methyl isobutyl ketone.

As far as exposure, I've been soaked up to my elbows in this stuff many times over decades, with no known effects so far (other than temporarily very dry skin) - I'm extremely healthy, and no spring chicken. I just had a look at the MSDS, and it appears that acute exposure (like drinking the stuff) can kill you or cause blindness, but typical skin contact or inhalation is likely to only cause various temporary forms of irritation like nausea or headache.

Good to know. I'm glad to have some practical feedback.

After I ran into the 'health and safety' people over the Hg manometers, I started to wonder how toxic the stuff really was and (if it was) how best to handle it.

I can understand the need to place highly structured warning/exposure information into an MSDS-like format -- especially from a litigation stand point. But, I think the sad thing about the culture surrounding the MSDS is it does't provide for any kind of practical knowledge of mitigating the risk.  A substance is either toxic, or not.  If its in the toxic category people start thinking about it like its an evil spirit -- you cleanse your labs of it using some prescribed ritual, preform the rites of paperwork, and are finally blessed by the high priest of 'health and safety' for continued operation. There's very little information available on what the risks are in a practical sense -- worse than 2nd hand smoke? More risk than driving to work... on a motorcycle? Personally, I'm not trying to avoid all risk in my life. There are benefits to risk. I'm trying to manage it. And to do that I need practical information.

For example, when I wanted to know about mitigating the risk of Hg exposure, I couldn't ask the health and safety people -- all they could say was "its toxic".... yes, yes, I'm aware of that... but if you think in black and white, so is table salt. Should I avoid that too?

You can't look in the MSDS -- all that says is its toxic at some mg/kg exposure. If you ask a chemist they say "go look in the MSDS". In the end I pulled anthropological  papers on gold mining in underdeveloped countries. The anthropologists detailed the ways these people dissolve gold with Hg and then distill the Au out -- and the ways they keep from exposing themselves (what's important to do, and what's not).

Anyway, my point is thanks for the info... :)
« Last Edit: March 03, 2014, 06:50:07 pm by CaptnYellowShirt »
 

Offline JoeyP

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Re: Everyone's Favorite Solvent?
« Reply #48 on: March 03, 2014, 07:24:24 pm »
I totally agree with you. I wish everything weren't "Known to the state of California to be carcenogenic" etc. It would be much more helpful to have some information as to the degree of toxicity for various levels of exposure. The MSDS sort of tries to do that, but doesn't attach any numbers that would help me judge the risk for my level of exposure.
 

Offline rstoer

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Re: Everyone's Favorite Solvent?
« Reply #49 on: March 03, 2014, 07:56:55 pm »
I can't get away from methanol. I used it for over twenty years when I had my electronics repair business. When I started in 1969 I bought it by the gallon at the local hardware store. By the time I sold out in 1992 we had to special order it from a lab supply for big $ (at least compared to the hardware store).

Your comment got me wondering about methanol. I've been using "Denatured Alcohol" for a long time, and thought it was mostly methanol. I buy it from Home Depot by the gallon. Doesn't say on the can just what it is, but does say it contains methanol, so I thought it was mostly methanol. Just looked it up, and found that it's about 50% methanol, 50% ethanol and a little methyl isobutyl ketone.

As far as exposure, I've been soaked up to my elbows in this stuff many times over decades, with no known effects so far (other than temporarily very dry skin) - I'm extremely healthy, and no spring chicken. I just had a look at the MSDS, and it appears that acute exposure (like drinking the stuff) can kill you or cause blindness, but typical skin contact or inhalation is likely to only cause various temporary forms of irritation like nausea or headache.
I tried denatured alcohol back when I had the electronics repair business and the methanol became hard to get. We found it damaged many plastics used in consumer electronics (I think due to the ethanol content) which made it unsatisfactory for our needs.
 


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