Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

The board I did on the new hot plate, between the clothes iron and the hot plate, preheated for 3 min @ 160C worked good.

Tried that on the next one, and got bad trace adherence and transfer.

Paper is turning brown. When I overcooked and smoked the paper it turned real brown...

Decreased temp to 150C and run a board. OK but not great. Still loosing traces.

Decreased temp to 140C. Much better, very little browning, good "stickage" and transfer, even of the fine alignment lines. But still some traces didn't adhere.

Got to thinking. Yeah, I know, a dangerous thing. I got really good results at 160C and 3 minutes, but only moderately good results at 150C and 140C for four minutes. Got to wondering if I was actually "cooking" the toner. Damaging the plastic with the heat.

Broke out the tiny type-K probe that came with the multimeter and a stop watch. Soldered the probe tip to the edge of a board, and had someone call out 10 second intervals as I wrote down the temperatures.


Heated between the good aluminum top hot plate and the clothes iron, both at 140C, the board reaches full temp in less than 60 seconds....

So any time I spend on the preheat, with my setup, beyond 1 minute is just overkill, and is probably baking the toner and making it non-sticky.


I figure run it for like 90 seconds, give everything time to reach pre-heat temp, then run it through the laminator.

Thoughts?