Hi, don't take me wrong i don't want to kill both your enthusiasm, but
forget the molten solder stuff. You will never do through holes with it.
And even for finishing purposes is a thing of the past. Most machines
used for that are forgotten on some corner or already in the junk for
various reasons. Roller tinning i have seen it foolishly buy new and
putted in the corner after first run (seller didn't accept it back).
PTH, is a chemical process of desmear + activating holes + copper
plating. There are almost 10 chemistries for that. Tin finish is done by
electroless chemistry. There are at least 4 very simple chemistries for
it.
On Thu, 2009-05-14 at 17:37 +0000, stuart wrote:
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "Daniel Howard Bryant"
> <coloradobryant@...> wrote:
> >
> >
> > I have not tried this, but I have thought about it a lot. My
> thinking was to use some sort of temporary solder mask(perhaps
> peel-able or regular) , mask off the entire PCB except where the via's
> would be, then dunk the entire board into molten solder, dunk into a
> solder pot like the 2000W unit sold by jameco.com (part# 149876),
> using some sort of ceramic tongs to hold the board.
>
> OK I had not thought of something like that. How would you attached
> the masks and what would make them out of?
>
> > If this method worked you would be able to make through holes on
> PCB's whose dimensions would be less than 12" by 8"(a lot of circuit
> can fit that area).
>
> The ones my contractor does with his electro-plating machine are all
> sizes from about 5mm square up to 400mm square.
> I would hope my idea would enable me to do the same.
>
> > My greatest curiosity to the above mentioned idea, is to how well
> would the joints hold up if one was to then reflow the board with
> components (I presume the surface tension of the solder would keep the
> joints sound...but only trials would prove the concept.)
>
> Yeah good point. I will try and find out how the pros do this.
> The contractor we use at work has a electro-plating line to do PTH,
> and I know he uses a reflow system, but it is very different to a
> toaster oven (lots of blets and flow solder baths).
> I would love to try to make an electro-plating system but I am not
> sure how to go about it so, based on what I have seen for sale by Mega
> I came up with the pressure roller idea.
>
> > Basically if you decide to reflow paper phenolic PCB's, make sure to
> let them dry out for a good long time before reflowing them.
>
> Thanks for the tip. I wonder if I could use an old toaster oven I just
> happen to have spare to dry the board first.
> A simple mod to the circuit I have to control the SMT oven would make
> something suitable for that.
>
>
>
>
>