Homebrew PCBs

Hello,

I am trying to mill the pcb (FR4) with a taig.

I did not have much luck with a uniform trace isolation even when I hold
the board flat down by clamping down on the board edges. It appears that
the pcb surface might not be uniform and that might be the reason why I
cannot remove/mill out the copper layer consistently. I read about using a
foot (http://hackaday.com/2011/04/22/pcb-milling-tutorial/) to push the pcb
down while milling, but, that was a bit too much for my skill level.

I read somewhere that it is easier to just paint the whole circuit board
with some paint and then remove/scribe the paint off wherever the traces
were being milled. This process is described here:
http://reprap.org/wiki/Scratch_n%27_Etch_PCBs . Just wanted to check if
anyone has experience with this?

On a different note, I read that "paper phenolic" boards are better/easier
on the mill and drill bits. I checked digikey and mouser and could not come
up with any "paper phenolic" boards. Wondering if anyone knows of a
supplier for "paper phenolic" boards?

I used the EM2E8-0625-90VC bit from
http://www.precisebits.com/products/carbidebits/scoreengrave.asp to mill
the board. Maybe, I need to use a 45 degree bit as noted in this article:
http://millpcbs.com/index.php?option=com_content&view=article&id=23&Itemid=47

Any thoughts or advice, please?

Thanks
Joe


[Non-text portions of this message have been removed]