Homebrew PCBs

I only use the thinnest cheapest Chinese ... 70x100mm PCBs  from EBAY

What do you mean by center punched?
Smacked a hammer and nail against the copper pads?
I would not mechanically abuse the copper like that.
Etch the hole ... with a PLUS sign to keep the drill bit from walking 
away from the target hole.

And etch time? 20 minutes?
I've been getting 4 to 6 minutes etching with room temperature.. same 
mix you do... 50mL muriactic acid to 100mL peroxide.

and
the only time it took longer is when the peroxide was low in the bottom 
of the peroxide container
soooooo....
I'm not a chemist so I can't declare why "old" peroxide takes 30 minutes 
while new peroxide takes less than 5 minutes.






On 11/22/2016 01:56 PM, kbyrne10@... [Homebrew_PCBs] wrote:
>
> I recently etched some thin brds .032 size with muratic acid and hydrogen
>
> peroxide per 3/4 cup muratic acid & 1 & 1/2 cup hydrogen peroxide 
> mixture. I coated the traces with liquid tin then center punched the 
> pads. I started drilling the pads with a dremel like variable speed 
> moto tool and brand new high speed drill bits only to have pads pull 
> away from copper clad brd.  Why did this happen? Does anyone know as 
> all I can tell is these are cheep orient type board stock bought in 
> large pieces from a E-Bay buyer. It also took 15 to 20 min to etch 
> boards at 120 degree temps. Professional positive brds in 1/16 
> thickness etched quite fast plus the pads did not pull away from 
> fiberglass
>
> at all. Am I right to assume that I got a bad batch of boards from 
> E-Bay. Any input would help me figure this one out as other board 
> stock did not behave like tis over the past 4 years also.
>
>