<DIV>Paul- I've got a nice RS UV exposure box that you can have to get you started, I'll send it to you via Business Post...if you want it! I develop large home made pcbs in a large developing tray (photographic for 20"x16" prints. On the cooker I have a glass/pyrex pan which allows you to bring the water up to a temperature so that when the FC crystals are added everything works quickly. I adgitate the tray with the PCB being etched, continuously. When I feel the chemical has to be heated up, I 'boil' the chemical again. It does not take me long to do a large board this way. Understanding missus- yes, I'm divourced, I know. Chemical, in my case, go everywhere, so you do have to watch that. Oh yeah, the sodium hydroxide used to develop the image is bought cheaper as 'drain-cleaner' in your hardware store. Go canny with this stuff- you only need tiny amounts. The boards that Rapid (cheapest) are supplying instruct you that they are now twice as sensitive to Sodium Hydroxide t!
han before. One can get a bit prissy about rubber gloves, lab coats etc. I've never bothered with that. I knock out excellent demo boards though! But some of my clothes, especially footware do look a bit of a state...</DIV>
<DIV>Regards, Ken- still thinking on ideas.</DIV>
<DIV><BR><BR><B><I>Neil Johnson <nej22@hermes.cam.ac.uk></I></B> wrote:</DIV>
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Hi Paul,<BR><BR>> I've decided its time to invest in some PCB etching gear.<BR>> I need a UV box and would like a bubble etch tank.<BR><BR>You'll also need bags of spare time, and a very understanding missus!! I<BR>used to make my own boards, and have a heated bubble-etch tank (bought<BR>from Farnell) in storage, as well as a bottle of ferric chloride<BR>(available most places), and a UV box (from Maplin).<BR><BR>You will also need a PCB drill and a selection of drill bits. If you're<BR>careful, buy tungsten-carbide drills, as they will keep their edge longer,<BR>but (a) they are more expensive than HSS, and (b) they are more brittle,<BR>so have a greater tendency to break.<BR><BR>You will also need a selection of plastic trays to develop and wash the<BR>boards, a lab coat to protect yourself from splashes of etchant,<BR>protective goggles to protect your eyes (you do not want ferri!
c chloride<BR>in your eyes...it hurts...) and some rubber gloves to protect your<BR>hands (ferric chloride stains your hands, making you look like a heavy<BR>smoker!)<BR><BR>Once your board is developed and etched, you then have to drill all those<BR>holes. Unless you want lung disorders, wear a face mask to stop the<BR>fibre-glass dust being breathed in, and/or a vacuum cleaner to suck up the<BR>dust.<BR><BR>As you may have gathered, I used to make my own boards, but now prefer to<BR>spend my time designing and building, rather than drilling more bloody<BR>little holes ("tedium" doesn't even begin to describe how dull a job it<BR>is). I know PCB Pool are not cheap, but when you consider how much effort<BR>goes into making a PCB, I would rather spend that time designing a better<BR>circuit, or improving the layout, than slaving over a bubbling vat of<BR>fuming ferric chloride, or coughing up fibre-glass dust.<BR><BR>> Can anyone recomend any particular brand? and also wh!
ere to get them (in<BR>> the UK)<BR><BR>Rapid Electronics s!
ell most
of what you'll need, including precoated UV<BR>PCB material. If I were mad enough to start out again I'd look at:<BR><BR>34-0760 Heated bubble-etch tank £200.00<BR>34-0695 PCB Production kit C £204.75<BR><BR>For larger boards you might need the larger UV box 34-0705 (priced at<BR>£207.30).<BR><BR>Assuming that you'll be using CAD to design your boards, I had excellent<BR>results printing to thin tracing paper in a laser printer, rather than<BR>clear film as the toner sticks better and gives more solid blacks and<BR>better definition. Remember to arrange it so the toner side is closest to<BR>the PCB, otherwise you get smudgy edges.<BR><BR>Neil<BR><BR>--<BR>Neil Johnson :: Computer Laboratory :: University of Cambridge ::<BR>http://www.njohnson.co.uk http://www.cl.cam.ac.uk/~nej22<BR>---- IEE Cambridge Branch: http://www.iee-cambridge.org.uk ----<BR><BR><BR></BLOCKQUOTE><BR><BR>http://www.macbethstudiosystems.com<br>Home of the M3X Analogue synthesizer...<p><p><br><hr size=1>!
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