DJ,
From my own testing, when using the "green stuff", you actually "flattening"
and evening out the toner a bit. After removing the paper, the toner is
actually filled with micro hills and valleys.The green film is based on a
high temperature mylar and this combined with heat evens out the toner.
There is nothing special about the green color, any color heat transfer film
works. I've tried gold and other patterns.
You can get a similar effect by using the silicone coated release sheet from
labels.
Myc
On Mon, Jun 1, 2009 at 12:57 AM, DJ Delorie <dj@...> wrote:
>
>
>
> Did another board today; the lines were big enough to use toner
> transfer so I did it that way, to try out the hotter laminator too.
>
> Things that didn't go so well:
>
> First time, I put the TT paper on the board and ran it through. Came
> out curly, I suspect the paper and board have different heat-expansion
> amounts. Second time I ran just the board through once, seemed to
> help. Since the first time through some of the toner came off,
> perhaps the pulling stress was a factor.
>
> First time, I put the hot board into the cold water. Not sure if
> stress was a factor here too. Second time I cooled the board first
> (see details below).
>
> First time through, the laminator had been at temperature for 7
> minutes. By the second time, it was plenty "warmed up". I also
> boosted the temperature from 350 F to 360 F.
>
> The green TRF seems to want to put down foil over the spaces beween
> close-together lines. This resulted in some micro-shorts. Not sure
> if the hotter temperature is causing this, but I sent my whole process
> to Frank (Pulsar) to see if he had any ideas.
>
> What worked:
>
> Board was prepped with soap and green scrubbie, as usual. Sanded with
> 2000 grit paper under running water until the water no longer beaded
> off. Dried the board.
>
> Artwork on TT paper as usual, nothing special here. Smallest details
> are 11 mil lines with 8.66 mil spaces. The printer doesn't seem to
> have a problem printing this.
>
> Laminator at 360 F. At least 10 minutes warmup, probably more like
> 15. Run board through once to preheat (cover copper with blank paper
> in case there's junk on the rollers), then three times with TT paper
> on it - short edge first, then long edge first, then diagonally. Once
> might have been enough, but I wanted to compensate for cheap rollers ;-)
>
> Place board on table saw (cold cast iron), board side down. Press on
> top (paper side) with push block, which has rubber sole. This held
> the TT paper and hot toner against the copper while cooling it, which
> took only a few seconds as the cast iron sucked away the heat.
>
> Put in cold water. DON'T POKE AT THE PAPER! It will come off on its
> own. I poked it the first time, again, that may have been a factor in
> the toner detachment.
>
> Dry. It was fairly well stuck; I could gently wipe it with a paper
> towel and nothing came off.
>
> Green TRF - one pass, short edge. Cool as above, peel. 100%
> coverage, aside from the issue with the micro-shorts it was nearly
> perfect.
>
> Etch, 4-5 minutes heated CuCl. Strip toner, tin plate.
>
> Cleaned up micro-shorts with an x-acto knife.
>
> To those who use TT without TRF: comments on how well toner alone
> blocks etchant? Do you get pinholes in the copper?
>
>
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