--- In
Homebrew_PCBs@yahoogroups.com, "rlspell2000" <rls@...> wrote:
>
> 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.
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> Paper is turning brown. When I overcooked and smoked the paper it turned real brown...
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> 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.
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> 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....
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> 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.
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> Thoughts?
>
I never do any preheating. I just set the laminator to 160C which is as high as it goes and then run the board through a couple of times. perfect transfer every time.