Is there anywhere I can read about the possibilities of solvent washing PCB's after I've soldered them?
I mean, I would like to remove all the flux spatter and the flux on the terminals. It leaves a tacky residue, it looks horrible, it doesn't help the join, if anything it helps attack it, and it's going to help stick other muck onto the join. I'd clean it off the terminals by hand, but there are too many and they're too complex; any kind of cleaning implement, like a Q-Tip, just gets taken apart after cleaning a single terminal.
I read that the guys who use wave soldering and such also submerge their boards in some form of solvent to remove the flux afterwards.
Is anyone familiar with this? Or does it only work for surface mount technology? Is it going to anhilate all the axial caps and resistors on a board?
I would assume that whatever solvent they use is very volatile so that it evaporates off all the surfaces quite quickly to prevent electrical failure. My main concern was that it would breach the seals of plastic encapsulated capacitors, clean the markings off components and so on.
I mean, I would like to remove all the flux spatter and the flux on the terminals. It leaves a tacky residue, it looks horrible, it doesn't help the join, if anything it helps attack it, and it's going to help stick other muck onto the join. I'd clean it off the terminals by hand, but there are too many and they're too complex; any kind of cleaning implement, like a Q-Tip, just gets taken apart after cleaning a single terminal.
I read that the guys who use wave soldering and such also submerge their boards in some form of solvent to remove the flux afterwards.
Is anyone familiar with this? Or does it only work for surface mount technology? Is it going to anhilate all the axial caps and resistors on a board?
I would assume that whatever solvent they use is very volatile so that it evaporates off all the surfaces quite quickly to prevent electrical failure. My main concern was that it would breach the seals of plastic encapsulated capacitors, clean the markings off components and so on.
Flux removers do exist: http://www.mgchemicals.com/products/413b.html but I use methanol. Very cheap, not drinkable and effective. I wash the pcb with a brush doped in methanol, dry it with a hairdryer and polish it with another large stiff brush.
/Hugo
/Hugo
Thanks Hugo,
I have been used surgical spirit, ethanol denatured with methanol, to clean it off up until now. One thing that annoyed me about the surgical spirit was that it left a slightly greasy layer behind on the board. I only know that it was denatured using methanol, but it may have also contained some other trace chemicals. Whatever it is, it needs cleaning off as well, as it makes the board slippery and mucky.
The surgical spirit was from a store, not a chemical supplier's, so they may have just not gone to any great lengths in purifying it.
You don't get this layer with pure methanol do you?
I have been used surgical spirit, ethanol denatured with methanol, to clean it off up until now. One thing that annoyed me about the surgical spirit was that it left a slightly greasy layer behind on the board. I only know that it was denatured using methanol, but it may have also contained some other trace chemicals. Whatever it is, it needs cleaning off as well, as it makes the board slippery and mucky.
The surgical spirit was from a store, not a chemical supplier's, so they may have just not gone to any great lengths in purifying it.
You don't get this layer with pure methanol do you?
I use pure methanol.
Indeed the pcb becomes grey/white.
I rinse it with methanol after scrubbing it very well with the brush. Polishing it with a hard brush makes it shine like new.
Left of picture unwashed, middle washed and right washed and polished with my favorite brush.
Some may have other tricks, I'd be happy to hear them.
/Hugo
Indeed the pcb becomes grey/white.
I rinse it with methanol after scrubbing it very well with the brush. Polishing it with a hard brush makes it shine like new.
Left of picture unwashed, middle washed and right washed and polished with my favorite brush.
Some may have other tricks, I'd be happy to hear them.
/Hugo
Attachments
The picture is a great help. The methanol sure does seem to work!
The white muck on your board isn't the same as the guck I was thinking of, but since it all wipes off, it isn't a problem anyway. The muck being left by the surgical spirits is more like a transparent, clear, oil. Soapy water cleans it off, but I'd rather not have to work round the terminals afterwards to clean muck off left by the solvent it's self. The board layout kind of prevents the brush cleaning method.
However... I HAVE AN IDEA!
Isopropyl!
Edit - I found some information on it here
click me...
Scroll down to the bottom. Since iso-propyl alcohol isn't taxed, even in it's chemically pure form, I'll try it out. Even if it is slightly less effective at flux removal, compared to ethanol, so long as it doesn't leave a film behind it's great!
Edit x2 - Even better... RS sells it! Search their catalog for IPA
The white muck on your board isn't the same as the guck I was thinking of, but since it all wipes off, it isn't a problem anyway. The muck being left by the surgical spirits is more like a transparent, clear, oil. Soapy water cleans it off, but I'd rather not have to work round the terminals afterwards to clean muck off left by the solvent it's self. The board layout kind of prevents the brush cleaning method.
However... I HAVE AN IDEA!
Isopropyl!
Edit - I found some information on it here
click me...
Scroll down to the bottom. Since iso-propyl alcohol isn't taxed, even in it's chemically pure form, I'll try it out. Even if it is slightly less effective at flux removal, compared to ethanol, so long as it doesn't leave a film behind it's great!
Edit x2 - Even better... RS sells it! Search their catalog for IPA
I use isopropyl and it works OK. Leaves a bit of residue.
The stuff they used in pc board shops was some kind of Freon. Nowadays they use water soluable fluxes though, so there's no need for nasty chemicals.
1.1.1 Trichlor works well but it's hazardous. Same with MEK. Laquer thinner and carburettor cleaner work too. Be aware that some solvents will destroy electrolytic capacitors.
Alchohol is relatively safe.
The stuff they used in pc board shops was some kind of Freon. Nowadays they use water soluable fluxes though, so there's no need for nasty chemicals.
1.1.1 Trichlor works well but it's hazardous. Same with MEK. Laquer thinner and carburettor cleaner work too. Be aware that some solvents will destroy electrolytic capacitors.
Alchohol is relatively safe.
Maylar,
That's kind of what was concerning me. I know that in commercial production the boards are either pressure washed with the solvents or submersed in it for a short period of time. But a lot of the components they use are also of the unmarked surface mount type.
I only want the solvents to dissolve the flux, but I'm sure all of them are probably going to dissolve the board's markings and component's seals as well. I'll keep reading and see what has been done.
I'm going to buy a roll of Multicore's 96SC Colophony Silver solder with my next order from RS. It uses Ecosol 105 flux. Is 105 water based?
Even still, while water may not strip the board of anything but the flux, it still takes forever to dry out of small pockets. I suppose deionised water would be a good idea, since it will be much less conductive should any be left behind.
Here's a note I found earlier -
"Cleaning: Multicore Ecosol 100 cored wires have been formulated to leave a pale flux residue and to resist spitting. Cleaning will not be required in most situations but if necessary this is best achieved using Multicore Prozone in a semi-aqueous process with a final rinse in deionised water. Other proprietary solvent or semi-aqueous processes including saponification may be suitable. Customers are advised to check the desired level of cleanliness is afforded by their chosen cleaning process."
That's kind of what was concerning me. I know that in commercial production the boards are either pressure washed with the solvents or submersed in it for a short period of time. But a lot of the components they use are also of the unmarked surface mount type.
I only want the solvents to dissolve the flux, but I'm sure all of them are probably going to dissolve the board's markings and component's seals as well. I'll keep reading and see what has been done.
I'm going to buy a roll of Multicore's 96SC Colophony Silver solder with my next order from RS. It uses Ecosol 105 flux. Is 105 water based?
Even still, while water may not strip the board of anything but the flux, it still takes forever to dry out of small pockets. I suppose deionised water would be a good idea, since it will be much less conductive should any be left behind.
Here's a note I found earlier -
"Cleaning: Multicore Ecosol 100 cored wires have been formulated to leave a pale flux residue and to resist spitting. Cleaning will not be required in most situations but if necessary this is best achieved using Multicore Prozone in a semi-aqueous process with a final rinse in deionised water. Other proprietary solvent or semi-aqueous processes including saponification may be suitable. Customers are advised to check the desired level of cleanliness is afforded by their chosen cleaning process."
Just put them under a hot shower for a couple of minutes, rinse with de-ionised water, then dry in a warm place for a day or so. This is the way I have cleaned many PCBs of dust/beer/food/flux etc. whilst servicing kit. If you have any really stubborn marks, or dirty pots, you can use a little diluted vinegar as a presoak before the shower.
Don't use any detergents, it will go horribly wrong!
Don't use any detergents, it will go horribly wrong!
maylar said:
lacquer thinner is part methyl ethyl ketone -- and a whole bunch of other ketones.
everyone be mindful that all these organic solvents are very flammable -- i clean my pcb's in the garage. isopropyl alcohol is usually pretty dilute when sold in drugstores.
also -- if you use a cloth to apply the solvent, don't store it with a bunch of rags after finished -- spontaneous combustion can result from the heat of evaporation.
ethyl alcohol is safe in moderation! sante!
Doesn't thinner, methyl, ethyl or isopropyl actually solve plastic parts like ICs and capacitor "caps"?
I use "safewash" to solve and "saferinse" to clean, btw. (google finds them, and even most electronic parts dealer around here know them as a couple).
They come with brush on a spray can, are not that flammable, rinse without leaving any film and are "safe" to parts and component placement prints.
Anyone with something better? Honest, I'd like to hear if there are some methods to do it cheaper and/or better...
Sebastian.
I use "safewash" to solve and "saferinse" to clean, btw. (google finds them, and even most electronic parts dealer around here know them as a couple).
They come with brush on a spray can, are not that flammable, rinse without leaving any film and are "safe" to parts and component placement prints.
Anyone with something better? Honest, I'd like to hear if there are some methods to do it cheaper and/or better...
Sebastian.
Could it be any cheaper than Pinkmouse's solution? Probably not.
My methanol costs € 2 for 1 liter. Pretty cheap too. In some countries the taxman probably wants his share of the methanol too which will make it rather expensive.
Once I had a very good fluid I bought from a guy. I never found out what it was but I guess it was a non chemical thing. It's called SIM-O-TEX and came in cans of 5 liter. A 1/5 solutions in water was enough to clean huge amounts of anything.
So if someone knows this liquid, give me a ring. I lost the guy and his product over the years.
/Hugo
My methanol costs € 2 for 1 liter. Pretty cheap too. In some countries the taxman probably wants his share of the methanol too which will make it rather expensive.
Once I had a very good fluid I bought from a guy. I never found out what it was but I guess it was a non chemical thing. It's called SIM-O-TEX and came in cans of 5 liter. A 1/5 solutions in water was enough to clean huge amounts of anything.
So if someone knows this liquid, give me a ring. I lost the guy and his product over the years.
/Hugo
Multicore make an organic flux solvent called Prozone.
This is a sweet smelling liquid sold in 1 litre containers - quite expensive but VERY long lasting - probably made up of ketones.
I pour an eight of an inch into the cap, dunk a used toothbrush, and gently move it back and forth across the pcb. It takes about 25 strokes at 20C to completely remove flux, but the results are wonderful. On completion I dunk the toothbrush in distilled water, and wash over the entire board, removing all traces of the solvent, although it's quite safe to dry without washing. I leave it out in the hot Australian sun for about an hour to dry, then lacquer it with a conformal coating. The results are marvellous, and the coating can be soldered through without problem.
Important: WASH YOUR HANDS THOROUGHLY AFTER CLEANING AND DON'T BREATHE THE SOLVENT VAPORS.
If you can't get Prozone, use high concentration isopropyl alcohol. It leaves a white residue, not as bad as methylated spirit (methanol), but it too can be cleaned off with distilled water.
Cheers,
Hugh
This is a sweet smelling liquid sold in 1 litre containers - quite expensive but VERY long lasting - probably made up of ketones.
I pour an eight of an inch into the cap, dunk a used toothbrush, and gently move it back and forth across the pcb. It takes about 25 strokes at 20C to completely remove flux, but the results are wonderful. On completion I dunk the toothbrush in distilled water, and wash over the entire board, removing all traces of the solvent, although it's quite safe to dry without washing. I leave it out in the hot Australian sun for about an hour to dry, then lacquer it with a conformal coating. The results are marvellous, and the coating can be soldered through without problem.
Important: WASH YOUR HANDS THOROUGHLY AFTER CLEANING AND DON'T BREATHE THE SOLVENT VAPORS.
If you can't get Prozone, use high concentration isopropyl alcohol. It leaves a white residue, not as bad as methylated spirit (methanol), but it too can be cleaned off with distilled water.
Cheers,
Hugh
Well, so it's isopropyl alcohol for solving and water for cleaning then?
I can adopt to the idea of exposing my plastic parts to alcohol for a short-enough-time
, but washing with distilled water actually isn't such a good idea (as i've read once ). It is too "reactive" (I miss that expression in English: reaction friendly) and could lead to oxidizing copper, if exposed for too long.
I like the idea of drying everything in the sun, as it reminds me of some burning-in but I usually apply SMT components. Water can stay very long underneath an IC (as it forms a capilar) and drying until you can't actually see any liquid any more wouldn't be safe enough here.
OTOH, it's not that I produce boards like hell, so doing it the intelligent way (depending on purpose and availability) would be good enough, anyway
I can adopt to the idea of exposing my plastic parts to alcohol for a short-enough-time
, but washing with distilled water actually isn't such a good idea (as i've read once ). It is too "reactive" (I miss that expression in English: reaction friendly) and could lead to oxidizing copper, if exposed for too long.I like the idea of drying everything in the sun, as it reminds me of some burning-in
but I usually apply SMT components. Water can stay very long underneath an IC (as it forms a capilar) and drying until you can't actually see any liquid any more wouldn't be safe enough here.OTOH, it's not that I produce boards like hell, so doing it the intelligent way (depending on purpose and availability) would be good enough, anyway
Honestly, for the DIY'er I like my method. I buy packages of "acid brushes" cheap at the local flea market. They are the ones that have cheesy 1/2" wide brushes on a metal tube. I cut the brush down to about 3/8" long with sharp wire cutters so it can be used as a stiff scrubber.
I tip the board on edge and scrub flux off with the brush and isopropyl alchohol. Put a rag underneath to catch the runoff. I keep the alchohol in one of those plastic bottles with the pump cap. I get minimal residue and the solvent is cheap and ~relatively~ safe. I wouldn't ever consider dipping my boards in anything.
There are specialy products available for flux cleaning in aerosol cans if this isn't good enough for you. Just search for "flux cleaning solvents" on the web.
I tip the board on edge and scrub flux off with the brush and isopropyl alchohol. Put a rag underneath to catch the runoff. I keep the alchohol in one of those plastic bottles with the pump cap. I get minimal residue and the solvent is cheap and ~relatively~ safe. I wouldn't ever consider dipping my boards in anything.
There are specialy products available for flux cleaning in aerosol cans if this isn't good enough for you. Just search for "flux cleaning solvents" on the web.
I use isopropy alcohol. The 90+% drugstore stuff. Lower %'s leave a residue. Actually 90% does too much it's minor. Scrub with an old toothbrush then rinse in warm tapwater and let dry.
I used to think washing a PCB with water was freaky since we are taught since childhood that water+electricity id baaaad. Ever since I was advice to clean a hot cocoa spill on my keyboard by putting the pcb through the dishwasher I've become a little more rational about it.
I used to think washing a PCB with water was freaky since we are taught since childhood that water+electricity id baaaad. Ever since I was advice to clean a hot cocoa spill on my keyboard by putting the pcb through the dishwasher I've become a little more rational about it.
Hugo,
the middle/right part of this PCB looks like if You haven`t washed clean enough.
When You brush or polish those areas (as on the middle of the PCB) this does not mean that You have removed the flux entirely - it just looks nicer.
I use spirit (in German it`s called Spiritus, not sure if "spirit" is the right word in English, ) and a stiff (shorted) paint-brush to wash my boards. After washing once, sometimes areas of the boards still look similar (those white veils) to the middle part of Hugo`s PCB on the photo - this means there is still flux residue and I repeat the procedure. Sometimes in extreme cases I have to repeat the spirit washing several times.
Spirit is cheap and not aggressive - it never happened to me that the spirit solved any kind of parts plastic materials - most other solvents are much more aggressive (in contrary for example it happened to me with a special flux-cleaning liquid that it solved some plastics).
After that I apply ordinary washup liquid (also with the brush) onto the entire board and brush it until it is very spumy and then I flush the boards with hot water.
Then I dry the board with pressed air until even the smallest drop of water has disappeared from everywhere (also under parts etc.).
After this the board looks perfectly clean and shiny without the slightest white veil of flux (or any other) residue.
The washup liquid takes care that the water drops off from the board easily (just like You do when washing up a wine glass very clean).
Thereafter I put the boards on a warm place (sun, heating, radiator etc.) for some time.
The repeating washing with spirit may take some time but it`s save regarding solving plastics, it`s not toxic (well, it doesn`t smell perfume but it does not have such penetrant or toxic odor as many other liquids have) it gives excellent results and it is cheap.
Be careful with acetone - it might solve some sorts of plastic!
I have used 99% (or the strongest you can get in the drugstore, they sometimes call it anhydrous) isopropyl alcohol to clean circuit boards. You need to scrub with a toothbrush to clean off all the flux residude. Canned "Flux-Off" solvent works even better. Stay away from acetone (really eats polystyrene caps), chlorinated solvents of any type (eats electrolytics alive from the inside out, slowly). Isopropyl is about as benign (and as cheap) as you will find for the readily available solvents. Don't use methanol, as it is quite poisonous - you don't want to breathe the fumes or let it touch your skin.
I tend to use rosin core solder becase it is readlily available, and I can live with the fumes. No-clean flux is very irritating to eyes and mucous membranes, the last thing you need to put up with when you're trying to buckle down and get a complicated circuit board stuffed and soldered. The residude is also hygroscopic, and can cause tracking, especially in high voltage applications. You'll end up having to clean off the residude anyway...
I tend to use rosin core solder becase it is readlily available, and I can live with the fumes. No-clean flux is very irritating to eyes and mucous membranes, the last thing you need to put up with when you're trying to buckle down and get a complicated circuit board stuffed and soldered. The residude is also hygroscopic, and can cause tracking, especially in high voltage applications. You'll end up having to clean off the residude anyway...
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