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Subject: [Homebrew_PCBs] Re: Consistency of TT (was TT for silkscreens)

From: "Dean Thompson" <deanthom@...>
Date: 2004-02-17

dkesterline wrote:
> That's pretty good results for a first time!
> Did you do anything special for the large copper area? As I mentioned
> in a recent post, when I print the large area, the toner isn't dark
> enough and I have to go over it with a pen- or I get etch through
> and 'pitting'.

Sorry I've taken so long to reply, busy making things work :) I didn't do
anything special for the large copper area. I have the printer set on the
darkest setting with no toner save. I just looked up the MSDS for the toner
in my printer (OKI 4w LED printer) and it seems to have a lower melting
temperature than other toners, 110C. Wether this helps I don't know. The
paper I am using is ordinary magazine paper, Jameco/Time magazine style.
Transferring with an ordinary clothes iron set on the highest setting, it
has a nice flat Teflon coated base without too many holes, which might help.
I've found if the toner has stuck well the paper will bubble up nicely where
the is no tracks.

> I've been TT'ing component print layer for a while now. Somthng you
> might want to try is "Jet PRINT PHOTO Multi Project Paper Gloss

Thanks for that tip, I might try that. The magazine paper does leave a bit
of a mess for silkscreens but if you are careful you can scrub off the paper
with only minor damage to the toner.

> Two problems I havent been able to overcome:
> I can't get a good layout transfer to the copper side of the board-
> including the component side of a DS board. Seems the paper won't
> conform to the uneven surface.

Are you using a clothes iron? What kind of printer are you using? I am only
new to this but I have a feeling that the type of toner has quite an
influence on the consistency of the transfer as well as paper. I don't do
much surface prep at all, just a scrub with a cheap kitchen pad (which isn't
very rough) under some hot water and the toner still transfers perfectly
with no dropouts. Maybe I'm just lucky but using what I have here and not
even going to any special effort I've managed to etch a few perfect boards
without dramas.

Have fun,
Dean