Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

I've always found tinning to be one of those things I could never get
the hang of the "traditional" way using solderwick.

Today I tried something which actually worked remarkably well and very
easy, solder paste and flux gel.

I mixed very small amount (a small blob on the end of a toothpick) of
solderpaste with probably 3 or 4 times the amount of a gel type flux
(Amtech type stuff from a syringe) until it was an even colour quite a
lot lighter than the original solder paste. Then I simply spread this
"weak" solder paste mixture over the (small) board, not too carefully,
with a toothpick.

Turned my handy clothes iron to it's hottest setting, flipped it upside
down, and sat the board on it.

The flux liquified immediately, and a minute or two later the solder
reflowed really nicely, a very thin shiny and reasonably even coating.
A couple of areas looked like they needed a bit more so I just touched
it with the toothpick that had some of the mixture on it and it
instantly wicked out and gave a better coat. I was surprised just how
well the solder coated from such a thin mixture (thinly and unevenly
applied at that). Admittedly this was on a ("from the failure drawer" -
the etch had too many problems) board which had a ground fill so there
was quite a bit of copper to "soak up" the solder.

Slide the board off, let it cool a bit, then wipe down with methylated
spirits to clean off the flux residue.

Naturally this won't work well with double sided boards, but a hot air
gun might do the trick in that case (I guess that'd make it something
like DIY HASL :))

The solder paste ("Best" in a "50g" jar, which weighed 26g when it
arrived) and flux (M-223, typical 10cc syringe) were both just cheap
ebay stuff.