Homebrew PCBs

On Wed, 07 Feb 2007 11:08:39 +0100, Sebastien Bailard  
<penguin@...> wrote:

> I'm looking for paper-reinforced epoxy since I've got this cnc-converted  
> mill
> and I was reading that I should stay away from glass-epoxy boards.
> Also, what are the guidelines on board thickness and copper thickness?

Might have a bit of a hard time finding it, although the parts suppliers  
here sell it. Surplus FR4 from ebay is far cheaper though.

> Do
> people typically use 1oz copper 1/6" thick boards for most projects?   
> (I'm
> building stepper controller circuits.)

Typical is 35u and 1.5mm thick (1oz and 1/16"). 18u is common because  
board houses use it plating it up to 35u, it will be fine for most  
applications and etches a little faster. You can also get 70u or 2oz  
boards, for high current or thermal conductivity (although again board  
houses tend to plate it on if they need more copper). Common thicknesses  
are also 1mm, 0.5mm, much more rarely thicker boards with 3mm. But you  
really want 1.5mm unless your boards are very small or something.

ST