Homebrew PCBs

> First off, I tried the unmodified laminator with some 32 mil boards.
> It worked fairly well and took about 8 passes through to get
> sufficient toner adhesion.  Basically, one needs to get the board hot
> enough to fuse the toner and that's why so many passes.  The trick is
> to keep the board in laminator as much as possible - as soon as its
> out, feed it right back in the front.

That's the impression i get too.
It's why i have made my fuser _really_ slow and only need 1 pass now.
It seems more reasonable to heat it in one pass to full temperature  
because obviously
there is no chance to cool in between. If you need multiple passes longer  
boards might
need more passes than shorter ones.



> I found that when feeding 64 mil stuff, you really need to make a
> *lot* of passes.  20 seems to work ok.  I did a number of boards, the
> largest being 6" x 2.75".  The results are pretty good - nicely
> uniform adhesion and reasonably clean traces.

that's really a lot of passes?
how long does one page take to feed completely?

>
> My biggest issue is alignment of the toner pattern for double sided
> boards.  The pinch rollers tend to pull the top paper so I had to
> resort to using an iron to tack the paper onto the board before
> feeding it.

I have exactly the same trouble and so far not found a reasonable  
workaround.

>
> So, is it better than ironing?  Yes but not as much as I would have
> thought.  The results are more uniform than ironing, especially for
> larger boards.  For smaller ones (2"x3" or so), an iron will produce
> similar results.  People who are making small boards won't benefit as
> much.  Also, given the number of passes you have to make, ironing is
> a little faster.  Another issue I found is that you need to let the
> device warm up even after the light comes on.  If you feed a board as
> soon as the light comes on, about halfway through the light will go
> off indicating that the board cooled off the heater.  I let it warm
> up about 5 minutes more.  Overall, ironing is faster.

Only with your GBC H200 which is in my opinion far from a good idea.
The fuser is really nice, i usually turn it on before starting to clean  
the PCB,
but it is hot a lot faster than that time. On pass (2 passes for  
double-sided or
broad tracks) is really not that long, and hugely easier than ironing.

>
> One thing I am thinking about doing is figuring out how to slow the
> feed motor to expose the board to more heat for a longer time.  The
> objective is to do the board in a single pass.  Anyone done that?

See above.


I thing the alignment problem could be solved by "tacking" the paper to  
the board
with a iron. I haven't tried so far. I must really find a solution to that  
alignment problem,
it is very annoying.

ST