--- In
Homebrew_PCBs@yahoogroups.com, Lee Studley <indigo_red@...> wrote:
>
> I still swear this:
> After the scotch brite and cleaner,
> the last thing to touch the board is either a wipe with acetone, or
> denatured alcohol (what I usually have on hand) and a quick little blow
> dryer to remove
> any moisture that condenses from the evaporation.
>
> -Lee
>
I, like Carl and Lee, have excellent results with just a Scotch Brite
pad and dish soap.
I scrub the board in hot water with a strong application of Dawn dish
soap( just plain 'Blue' Dawn as it cleans and cuts grease and doesn't
have any extras). I apply a few drops to the board (a generous
concentration of Dawn) and scrub with a green Scotch pad in both
directions until all is smooth and shiny. Then I rinse well and blot
with a plain cheap white paper towel. That's good enough to do the
trick every time. Sometimes the board gets handled afterwards (such as
forgot to drill the alignment holes) in which case I'll wipe it with
99% alcohol before applying the TT. I soak part of a plain white paper
towel with the alcohol and wipe the board good on both sides. I let it
air dry as the alcohol is 99% and it dries clean. Many solvents don't
dry clean as they are petroleum based and leave an oily residue or
other films behind. Those who remember the old days know there are
only two solvents acceptable for cleaning tape heads ... Freon TF
(good luck finding that one anymore) and 99% alcohol, because these
both leave no residue behind. I always use alcohol for a final wipe if
I need one.
I use Toner Transfer and never have a bonding problem with this
method. Always 100% on trace adhesion with old or new boards. Micro
etching the board is simply not necessary for this process.
One other note, I've seen references to sanding with some pretty
coarse grits. I'd be careful of using the sand paper as 1oz copper is
only 1.34 mils thick (0.00134") and 1/2 oz copper is half that.
Sanding would significantly reduce the thickness of the copper
possibly leaving it very thin in some areas. I'd personally hesitate
to use anything coarser than 600 to 800 grit (and wet) myself.
phil - KA0HBG