Sunday, 13 June 2010

Pretty in Patras

The weather has been too bad to permit of further developments on the magnetic loop antenna (not strictly true - I have made v0.2, which has a 0.7m diameter main loop and does resonate in the 30m band - but the weather has prevented any outdoor testing). Accordingly, I was looking for something to do in the shack...

Yesterday, whilst strolling around Tesco, I slipped a laminator into the trolley...


The model number is H0L09 and I paid about £21 (there is a cheaper "Tesco Value" laminator at around £15, but the model I chose offers hot or cold laminating and a release feature - which, I figured, meant that the roller spacing can be changed - important when you're trying to squeeze thick PCB through the machine!)

Anyway, this afternoon I decided I'd see if it makes PCB production any easier - with GREAT results!

I decided to give Alberto's junk-mail paper stock method another try, this time chosing a page from the Patra summer catalog. Patra is a sort of up-market Cotton Traders. I don't know if the name derives from the eponymous city on the Peliponese (where my friend leads the Audio Group of the Wire Communications Laboratory) but the catalog is full of pleasant images of even more pleasant YLs, many of whom have dark hair and look as if they could hail from Greece.

I prepared a trial PCB pattern (actually the layout I'd made for Francesco, ik3oil's Frequency Counter, as previously used in my Funster Plus ), cleaned up a piece of copper-clad board and passed it through the laminator.

It goes through smoothly enough - but the machine does emit a few groans and sighs during the process!

I didn't count, but I guess I passed the board through twenty times, before putting it in a cold water bath. Sure enough - just as Alberto promised - the paper soaked away cleanly, leaving a PERFECT transferred pattern. Most wonderfully of all, there was NONE of the irritating "chalky" deposit between the traces that has compromised so many of my recent attempts at PCB manufacture. In fact, THIS IS THE CLEANEST, SIMPLEST RUN THROUGH THE TONER TRANSFER PROCESS I'VE EVER ENJOYED.

There were some "paper fibres" left on the toner, clearly visible in the photo below...


... but this is irrelevant to the final quality of the board, which is seen here after etching and trimming to size (I've still got to drill all those pesky holes)...


To be hyper-critical, there is a tiny degree of "porosity" in the ground-plane (but I think selecting a thicker layer of toner in the printer settings and - perhaps - a few minutes less in the etch bath - will fix this). That aside, this is a really significant improvement in the m0xpd PCB process.

Thanks to Alberto.
Thanks to the Tesco Laminator.
Thanks to the pretty girls of Patra.

...-.- de m0xpd

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