Quick cleanup tip - flux removal

[Mark Hammer]

If you are like me and pre-tin your boards with liquid flux and solder, or if you have an older E-H or MXR pedal and find their "manufacturing style" (complete with blobs of solder) a little ugly or messy, or if you are trying to debug a board and want to be able to tell the difference between flux and a solder bridge, or if you have modded something and simply wish to make the modded portion of the board look as neat and nice as the rest of it, you will likely be interested in knowing how to get flux blobs off the board.

While there ARE commercially available bottles and spray cans of substances calling themselves flux remover, I was very pleased to find that a much cheaper and readily available substance work beautifully as a flux solvent and remover: methyl hydrate, AKA paint thinner, methyl alchohol, or wood spirits.  You can find this just about anywhere you can buy paint.  A small dab on a Q-tip quickly dissolves any flux in the immediate vicinity, and you can use the other clean end of the Q-tip to wipe away the dissolved flux and residue.  Very little stink, relative to other solvents I've tried in past (e.g., acetone).

Just make sure you are mindful of all the safety instructions on the side of the container, and don't leave it where kids can get at it.

[tranceracer]

Mark,
Thanks for sharing, I was looking for an alternative for my acetone.  For one it smells and two, evaporates to fast.

Does any or all of those solvents work on removing the toner trace from the copper board?

-tR

[Mark Hammer]

Funny you should ask.  I whipped up a couple boards over the weekend, and methyl hydrate did diddley squat as far as dissolving toner.  Personally, I just use 220-400 grit sandpaper followed by buffing with fine steelwool.  You're going to want to buff the copper anyways.

Though not germane to getting rid of things adhered to the surface, I'll just mention in passing that I've been changing the order in which I do things over the years.  I used to etch, buff, tin, then drill.  Eventually, I moved to etch->buff->drill->tin.  Yesterday, instead of removing the toner before I drill, I decided to drill first and then sand/buff (etch->drill->buff->tin).  I found that the larger targets provided by white dots in the middle of the black (remnants of the phot-paper emulsion that got dragged to the board when I peeled the paper off) made it far easier to visually centre my holes for ICs than the usual process of cleaning the etched board to a shine and searching for the little dimples in the middle of the pads.  That may be a function of my eyesight and lighting conditions on the bench (I don't have one of those laser-sighted drill presses either), but I found the toner pattern assisted in lining the bit up with the pads.  YMMV, but I'm sold on it.

[jrem]

Mark,
Thanks for sharing, I was looking for an alternative for my acetone.  For one it smells and two, evaporates to fast.

Does any or all of those solvents work on removing the toner trace from the copper board?

-tR

Aerosol brake cleaner takes toner and flux off, works great, fairly inexpensive, too.

[Papa_lazerous]

I always drill with toner still on for the same reason of making it marginally easier to centre the drill, also if you drill the holes and end up deciding not to solder the board for a while the copper doesnt tarnish as its still protected by the toner.  when you tin are you using a liquid fluz pen then applying the iron and lots of solder or what?

[Mark Hammer]

when you tin are you using a liquid fluz pen then applying the iron and lots of solder or what?

I have some thinned out liquid flux that I apply with a Q-tip then apply just a dab of solder here and there and spread it around so that it is thin.  Just a little goes a long long way.  I do it for the same reason you leave the toner on; to prevent tarnish over time before component installation.  I tried liquid tin once but it just didn't cut it for me.

[Papa_lazerous]

what is a Q-tip?  It doesnt translate too well from American to English 

[Mark Hammer]

Cotton-tipped swab, suitable for cleaning out your ear.  The same sort of thing we used to use for cleaning tape heads back in the day.

[Papa_lazerous]

ahhhhhh

Q-tip=cotton bud