Homebrew PCBs

On Fri, 15 Jul 2005 22:56:05 +0200, <JanRwl@...> wrote:

> One point I have never seen touched-on in this group:   Much copper-clad
> (all?) seems to be manufactured with 1/2 oz. copper, as MOST  boards are  
> "plated
> through" after drilling but before resist is applied, and  tin-plated.   
> Then,
> the copper is "1 oz."
> I picked up some ca. 4" wide x 3' waste, double-sided copper,  from a  
> local
> PCB house (they explained anything narrower than 4" just won't work  in  
> their
> plating- and etching machines, so once stock gets that narrow, they   
> scrap it).
>  It etched MUCH faster than I THOUGHT I had used before, and I  did some
> forensics.  That prompted a call to the PCB house folks, and they   
> confirmed, they
> buy-in 1/2 oz. stock, as it is less expensive than 1  oz., so saves  
> money,
> etchant, and time.  What about this,  Gang???            Jan  Rowland


fact, not fiction ;-)

I too have loads of 18u board that is intended to be plated.
No problem with using it, just use wider traces accordingly.
Etches faster etc, as you say.

Cutoffs from board houses are really cheap, even at ebay, and many are  
wide enough for all boards i want to make.


I would not prefer to buy board cut to a specific size, as i need a few mm  
spare on one side for the clamp in the etcher.
Also, if i want a finished board of a certain size, i cut it bigger first  
and only trim it to dimension after etching, i wouldn't like having to  
align precisely. Starting out with bigger pieces gives me less  
cutoff/waste as i can divide it like i want. The small strips that i cut  
off after etching (from 5mm to 2cm or so) are great for loads of stuff,  
 from mixing two component glue to becoming a part in someting else i build  
etc..)
I inspect boards carefully before drilling, if it is unuseable for some  
reason i prefer getting bare FR4 without holes, as it is useful for many  
things.


ST