Peter Restall wrote:
> Thanks for all the replies; there were some good suggestions there that
> pointed me in the right direction.  I've managed to do my first TT board
> after a fair bit of experimenting and elbow grease.  Brother OEM TN3130 
> and
> TN3170 toners (for HL5240 / HL5270 printers) seem to work alright for TT.
> If anybody's interested, the method I used in the end was:

Peter, looks pretty good. I do have a couple of questions.


> 1). I used some fairly thick glossy magazine paper, with as little print 
> as
>    possible on it (regular paper had too many fibres, so touching up 
> tracks
>    afterwards was impossible without bleeding - and photo paper just 
> wouldn't
>    come off the board in the water).

Have you tried printing on the backing of a shipping label (or similar)? 
Someone recommended this recently, and it sounds like it could have helped 
you avoid transferring the magazine print onto your PCBs.


> 3). I used the 'thin paper' setting for the printer so the toner on the 
> page
>    wasn't fixed at as high a temperature.

Are you sure this setting sets the temperature? IANAE, but AFAIK the media 
setting affects the voltage of the corona wire. Does anybody know for sure?


> 4). The board was rubbed with acetone, scrubbed vigorously with a green
>    pan-scrub and washing-up liquid, and then rubbed with acetone again 
> until
>    there were no more smudges or marks on the paper towel.

Do you think there would be any downside to using fine grit sandpaper, prior 
to using the dishwashing liquid?


> 5). When ironing, I had the iron at its hottest setting and leaned on it 
> for
>    two minutes (no movement).

Was rubbing (as opposed to leaning), producing bad results?


>    I flipped the board over and did the other
>    side the same.  Then I ironed both sides of the board in a side-to-side
>    motion, with some downward force again.

How did you align the two sides so perfectly?


> 6). After ironing I stuck the board in cold water (without any soap) and
>    left it for 15 minutes.

Do you think it is critical to use cold (as opposed to slightly warm) water, 
without soap?


> http://custard.restall.net/bertha/images/dscn1664.jpg
> http://custard.restall.net/bertha/images/dscn1670.jpg
> http://custard.restall.net/bertha/images/dscn1671.jpg
> http://custard.restall.net/bertha/images/dscn1674.jpg
> http://custard.restall.net/bertha/images/dscn1675.jpg
> http://custard.restall.net/bertha/images/dscn1676.jpg

Good work!


> Fairly pleased with the results of the board (very good toner coverage and
> no broken tracks).  The only disappointments are the black mottled look 
> and
> the fact that my drilling was atrocious - really let myself down there :(

Don't be so hard on yourself, the soldering job wasn't your best work 
either... just kidding! :-D


> But overall results were comparable to photoresisting, so I think it's
> definitely worth doing again since it's such a cheap (and pretty quick) 
> way.
> Until I get my CNC machine sorted of course...

You'll post some videos once it's working, right?

Vitaliy 

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