scruff
Part of things
Posts: 621
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Wow, I love it when a plan comes together.
I don't think any of my projects has worked first pass.... Usually there is a degree of smoke and swearing!
(Mind you my recent projects have all involved boosting 12V to 200VDC or 400VDC which makes things more exciting!)
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1994 Lotus Esprit - Fragile red turbo with pop up lights. 1980 Porsche 924 - Fragile red turbo with pop up lights.
I spy a trend...
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Toy RobotsDeleted
@Deleted
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Nov 16, 2011 18:56:23 GMT
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ace stuff !!! never realised it could be so simple to make a pcb board... might have to google that a bit more
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Nov 19, 2011 23:58:25 GMT
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I've let this thread rot. I'll pull my finger out and post an update soon. The PCBs take a bit of practise to get right, and I found the stuff I read on the web wasn't quite right for me. My secret sauce is: Prep the copper by a decent rub over with 600 grit wet n dry in soapy water (hand soap seems to work ok). The last quarter inch around the edges needs particular attention as it's where finger pressure drops off as you go over the edge if you see what I mean. Dry with paper towel and a quick wipe over with neat acetone on a paper towel. Careful to only pick it up by the edges after that. I had absolutely no luck at all with photo paper as some folk on the net suggest. I find a centre page out of the BT's regular junk mailshot, preferably without too much print on it seems to work best. Make sure you don't handle it too much as finger grease really knackers the results. That's a page from a cheap magazine in the photo above which is also fine. Basically you're looking for a full colour page with a satiny finish. Lidl's Monday Madness pages are too thin and get jammed in the printer, pages out of quality mags are a bit too thick and the clay surface doesn't separate cleanly, for me anyway. I print off several copies of my artwork on the same page and cut out the one with least streaks in it on the whitest bit of page. I use a Lexmark monochrome laser printer as it was cheap to buy and run and gets used a lot for other stuff. The Lexmark toner works ok if you turn up the darkness a bit. Cheap toner refill off ebay was just a terrible gooey mess when ironed, but a decent refill kit from www.tonertopup.co.uk/[/ur] works best of all. I use the normal 50% setting on my printer. Ironing it on, I set the iron to just off the maximum temp, no steam. I put a wad of newspaper underneath and a bit of greaseproof paper on top to stop the gloss off the other side of the paper getting baked onto the bottom of the iron. I don't push down or rub the iron around too hard as the toner will tend to flatten out and you end up with bridged tracks. You have to push a bit though and move the sole plate about some to avoid cold spots where the toner doesn't stick. Takes me about a minute overall, depending on the size of the copper board. I have a bit of cold water ready in the sink and I just drop the hot board in it immediately after ironing so it sizzles. The paper will blister and soak off really quickly, but I use a dish sponge scourer to get the remnants of the paper off and leave crisp black edges. You can go at it quite hard as the toner sets like concrete when cold. The gloss (clay) in the paper comes off in tiny flakes which get embedded in the toner. You need to break up those flakes as much as possible to avoid masking the gaps in places and bridging tracks. It's easy to to double sided boards. Just align the front and back artwork on the page and leave a half inch gap between them. Cut round the both of them together and fold the paper over so they lie face to face. Hold the paper up to the light to get the alignment spot on and make the crease really sharp to keep it in place. Then just slip the double sided copper board into the fold and iron it on both sides. I can do pads on a 0.5mm pitch without too much trouble now. I might have to run a scalpel blade between the odd adjacent tracks where the toner has splurged a bit under the iron. If the ironing goes totally wrong, it doesn't take long to clean all the toner off the board again with the wet and dry and have another go (another reason for printing several copies of the artwork onto the page).
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