PCB Cleaning

Check an LED first. Those transparent plastics aren't as tough chemically or thermally as IC-type epoxy. Otherwise, should be fine.

John

I'd say no and err on the safe side. Acetone can do nasty things to plastics.

Just soak in methylated spirits for a few minutes, much milder on both the hardwar and your lungs and fingers.

I'm not sure if the name methylated spirits is used globally - maybe you know it as denatured alcohol ???

You really do not need to use nasty toxic organic solvents that may spoil components. You can buy proper pcb cleaning stuff from Farnell or anyone similar. I recomend ( and use) Safewash which is water soluble. (You need to rinse several times in de-ionised water and then dry). It comes in 5l packs or

Michael Kellett

I think acetone, MEK and similar solvents are too harsh. They can dissolve or swell some plastics and may damage components.

I use 91% isopropyl alcohol or denatured ethanol both are mild and work well. Use a small brush to loosen flux then wipe with a soft clean cloth. Re-do if any residue remains.

Do you think the epoxy used in making the PCB might react?

I would not "soak" anything in a solvent other than something like a metal or other NON-porous material.

PCB material is VERY porous, even though it may not appear so.

It is epoxy and fiberglass.

I've never seen a pcb be affected by a short time in acetone.

If an little acetone did penetrate into the edge of the board - which it won't - it will evaporate in an instant. And it's non-conductive.

John

"...soak for several minutes" is NOT "a short time".

...but as acetone evaporates, the area gets cooler and water condenses, adding to the water in the acetone.

Alcohol worked pretty well. It left a small amount of residue in some areas(white stuff which I have no what it is) and didn't get teh really burned flux off well. I'd say it was about 97-99% effective in removing the flux but not greating in making a pretty board. Luckily I only care about looks with my women ;)

Once the heavy buildup is loose, put paper towel between the board and the brush and repeat allowing the papertowel to absorb the liquified flus and alcohol mix.

As I understand it - the alcohol is a non-polar solvent and removes the rosin component of the flux. The white crap left behind is acid salts. These need a polar solvent like water to dissolve and remove them. Do alcohol first then brush & rinse with distilled water. Then bake off on a cool oven. The boards come up nice & shiney with no streaking or crap left behind.

IPA tends to leave white residue when used to clean rosin flux.

For really clean boards, the last step should be a squirt rinse with clean solvent.

John

Unless leakage matters!

John

Not the same thing. Methylated spirits is methanol, denatured alcohol is ethanol with something really bad tasting added--used to be benzene, now usually kerosene IIRC.

Cheers

Phil Hobbs

Alcohol is a polar solvent like water. Nonpolar solvents are things like gasoline and xylene.

Cheers

Phil Hobbs

No, "Traditionally, the main additive is 10% methanol, giving rise to the term methylated spirit"

Denatured, in general, can include bitter stuff, but AFIAK benzene and such were removed a long time ago because people kept dying or something. OTOH, the article also says British regs add mineral spirits.

Tim

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IPA dissolves the rosin. The white stuff left over is not soluble in IPA but is soluble in water. I always follow IPA cleaning with a good scrubbing w/toothbrush and warm water then blow dry. Baking in warm oven is optional. al

No, methylated spirits is ethanol with *some* methanol added. Additionally, sometimes a bluish tint is added with dye, and at one time at least pyridine was added to provide a distinctive odour.

By alcohol I was referrring to 190 proof Everclear from the liquor store. Seem I always have some handy for some reason. Keep the cap closed tight so it doesn't absorb water.

I've never had a problem with white residue.