Making PCB's? Child's play - literally!

[Yorkie]

I abandoned ferric chloride as an etchant some years ago when I found out about sodium metasilicate (often termed 'metso'). It's in the form of white crystals and when mixed with water, is clear. It etches more quickly if the water is warm - about 50C, and as the exposed copper is etched away, (15 mins or so), the etchant becomes light blue but doesn't form a ghastly sludge, unlike ferric chloride. It can be used several times over if carefully stored in a marked non-metallic container. It's not expensive to buy and widely available on e-bay etc.

The reason I found the link to the bright little lass was that I was searching for info on using the laser toner/iron on method of applying PCB artwork to the plain board preparatory to etching. For many years I've used the UV light box technique, using artwork printed onto OHP transparency sheets. I used to get excellent opaque tracks printed on an HP Photosmart printer till it gave up the ghost last year. I did some research to choose a new printer to e what I'd hoped would be similar or better results. I chose an Epson SX535, which was about three times dearer than budget printers at the time, and had assumed tat it would print transparencies. Big mistake - it's hopeless. I contacted Epson 'helpline' (a oxymoron if ever there was one) and was told in a very casual way 'well of course you can't print onto acetate with it'. Basically, from that angle, it's just landfill. (I don't think other current makes and models of ink-jet printers are any better on acetates).

Hence, I thought that at some point I might get monochrome laser printer to try the 'iron-on' method and abandon the UV technique, which in any even produces variable results depending on factors such as the exposure time and developer concentration. All you need to use for paper on which to print the iron-on artwork in the laser printer is glossy paper torn from magazines such as newspaper supplements. It doesn't matter that it already has print on the paper - the laser toner isn't like ink. (Sylvia explains in the video!)

I'm still a bit sceptical about the technique and haven't heard first hand from anyone who has used it. I'll perhaps have to sub-contract the work to young Sylvia - she's got the job well sorted! (PhD by 22? Professor by 32? CEO of Apple by 35? Nothing would surprise me about that kid - what a star eh, and what fun to be around!)