[chbot] PCBs

Mark Atherton markaren1 at xtra.co.nz
Wed Oct 21 00:55:57 BST 2020


Thanks for posting this with suppliers.



On 21/10/2020 12:20 PM, Russell & Heather Phillips wrote:
> Hi All,
> What you need to do your own PCBs.
> Print out design normal for top layer but inverted, bottom layer mirror 
> and inverted.
> Use special film to print your design on RS components P/N 286-6773 A4 
> size on a laser printer. I use our HP Color Laserjet Pro MFP M281fdw, 
> does excellent black, colour, both sides and is not expensive.
> silk screen pcbs with negative photo resist PER-20 using a 100 mesh 
> screen and squeege, all available from Uniscreen 31A Inversen Terrace. 
> bake pcb at about 60 degrees C in an oven, boards will keep for years 
> and not effected under led lights.
> After Using the silk screen clean with Acetone. From the 'Spray store', 
> also from them I use 2 way thinner and MEK for gluing ABS air pipe to 
> the fittings and pipe running from compressor to garage, workshops and 
> Heather's weaving/ sewing room for her air operated computer controlled weaving 
> Loom. To glue the fittings on etc. Make a glue by dissolving scraps of 
> ABS in MEK. If buying from the 'Spray Store' minimum is 5 litres so if 
> you want a small amount I can give you some (I will be pushing up the daisys before I use 
> it all).
> ABS pipe and fittings from PSL Total Air 30 Sonter Road
> Apply the negative art work black side down on pcb under glass expose 
> with UV light source long enough to harden the coating that is exposed 
> through the clear parts and should not wash off if the exposure is long 
> enough.
> My light box is 4 Philips TL 20W/05, now you would use UV LEDs. In my 
> case when I used 5 minutes exposure the board was wiped clean but 7 
> minutes is good, with the new film the black is very dense so is not fussy.
> Make up the DP10 developer from RS components P/N 489-9113  in 1 litre 
> of water at 25 degrees C, immerse  board then after a while brush it 
> down and wash under the warm tap, it is now ready to etch.
> I use Ferric Chloride now available from Element14, Heat to 80 or so 
> degrees, aeration and agitation is the key to getting the copper off 
> quickly, for small boards a 2 liter preserving jar is excellent, half 
> fill with Ferric Chloride,
> heat up in hot water then take lid off, drop in pcb, screw lid on 
> violently agitate and the copper will be stripped off in double quick 
> time. Now I use 'Dipsy'.
> She is made of Perspex, alkathene etc and the best part is the pump I 
> bought from Aliexpress, Magnetic Drive Pump Model MP-6RZ about $40. This 
> solved all the pump problems.
> Perspex and Chloroform for gluing from FAB Plastics Limited.
> Alkathene 16mm used to heat the etchant (garden irrigation pipe)
> Cheers,
> Russell Phillips.

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