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Dingdoc

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Joined: 23/09/2009
Location: Australia
Posts: 76

Posted: 01:22pm 29 Jan 2013

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Klaus

Please let me know what sort of results you get - as I said before, some brands of toners work better than others so it would be interesting to compile a list of the ones people have found to work well and those which don't.

Just a comment too on using the PVA glue. Try to make sure it is a really thin bead along the edge. I put a spot of it about the size of a grain of rice on the end of my finger then slide it along the very edge of the tt paper. This amount dries within minutes.Too much glue wrinkles the paper and could also transfer to the rollers in the printer possibly damaging it. I also allow 10-20 mm extra paper along the top edge so that it can easily be cut away from the backing sheet.

Another helpful hint is to preheat the blank pc board by leaving it laying on top of the laminator while it heats up for 20 mins or so.

Regarding the Lowell laminators, I suspect that they do not apply even pressure right across the width of the board due to flexing of the roller axles. This seems to be more of a problem with the thicker boards due to limited travel at the spring loaded ends of the rollers. When I get more free time I plan to have a closer look to see if I can make some improvements here.

Regarding the chore of drilling, I must admit to often getting slack and simply mirroring the pattern then mounting the components 'surface mount' style on the copper side of the board. It does not look pretty and can be tricky with the soldering but works OK for quick lashups.

Regards
Trev

MOBI
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Joined: 02/12/2012
Location: Australia
Posts: 819

Posted: 01:37pm 29 Jan 2013

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Regarding the chore of drilling, I must admit to often getting slack and simply mirroring the pattern then mounting the components 'surface mount' style on the copper side of the board. It does not look pretty and can be tricky with the soldering but works OK for quick lashups.

That is a trick I used in the 70's and got "growled at" because it wasn't mechanically strong. I couldn't see a problem with it, so I did it anyway. That was before SMD was the norm. The best part was, there was no drilling.

It was also easier to replace faulty components - no cutting IC legs and removing pin by pin. Wish now I'd patented the idea.

David M.

Tinker

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Joined: 07/11/2007
Location: Australia
Posts: 1904

Posted: 04:58am 17 Mar 2013

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Today I had a chance to use the TTP (toner transfer paper) that 'dingdoc' mentioned above.
It performed much better than the other two TTP's (Pulsar & Altronic's blue) I had tried. And its so cheap, I got enough for many projects now.
A hint for others: it is shipped in A4 pages rolled up and is too 'curly' to use straight away. But a few days under a heavy book straightened it out easily.

I did find the backing was not lifting off by itself after a prolonged soaking but picking up a corner with tweezers and carefully pulling it back did the trick.

Another thing I found is the green TRF (toner resist foil) from Pulsar works very well with it. With Pulsar's TTP I got at best about 75% TRF coverage, with the cheap Chinese TTP the green TRF coverage was 100%.

The toner by itself on the blank PCB is still porous even though the Chinese TTP had transferred all of it. Putting the green film on top of it produces PCB tracks of a much better quality.

I did use the same Samsung laser writer & toner cartridge as well as the same Lowell laminator for my boards but I have no idea why the green Pulsar TRF works better on the Chinese TTP than on Pulsar's own TTP.

Klaus

Dingdoc

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Joined: 23/09/2009
Location: Australia
Posts: 76

Posted: 11:01pm 17 Mar 2013

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Glad to hear you are happy with the tt paper Klaus.

Also interested to hear that it works with the Pulsar TRF as well. I had planned to try that on a board if I was not happy with the straight toner results but never had any noticeable pinholeing or etch-through problems. The HP laser printer has a 1-5 density choice and I have mine permanently set on the max of 5.
The only downside of this is that it may be affecting the resolution of boards requiring extreme res such as the ones required for the 100 pin sm pic chips. I did a test print of one of these and the pads all ran together. Perhaps lower print density along with TRF may have been better - will try it one day.

Incidentally, I even managed to make a 'perfect' board with that paper once, in spite of forgetting to clean the blank board first. The board was fairly new phenolic with no tarnish but had fingerprints all over it.

You may ask why I use phenolic. As much as I dislike it I got dudded by an os seller - It was advertised as FP4 glass board - buyer beware!

In that regard, does anyone have a supplier of blank glass board they would recommend?

Trev

Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 12:07am 18 Mar 2013

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Trev,

Aztronics here in Adelaide often have PCB offcuts at a budget price, If you contact the guys tell them i sent you to them and Pete said they will look after you.
I know all the staff well and its my favorite local electronic supplier. (great service and excellent prices)

If you want i can pick you up some board and send it down with Gordon on his next visit seen you are around a few 1000m apart.

Pete.

Sometimes it just works

Dingdoc

Regular Member

Joined: 23/09/2009
Location: Australia
Posts: 76

Posted: 02:54pm 18 Mar 2013

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Thanks for the offer Pete
Will PM you
Trev

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