If some one tries this can sum 1 mail me pics as I cant find my shiny paper atm Things to remember 1 check all of this yourself cos I don’t know how safe some of this is 2 I do not recommend a drinks bottle it is a very bad idea as they tend to leak slightly after 1st opened and someone might think it’s a drink (though I don’t know what drink youll see what I mean if u make any up 3 I do not take responsibility for anyone else I am saying I did it this way and it worked 4 be VERY VERY VERY careful this acid is nasty stuff Tools needed 1 a laser printer (picked mine up from a car boot for £3) 2 either some shiny paper (the stuff you print @ high quality on) 3 some copper clad board 4 some etching acid (I used Ferric Chloride (FeCl3) from maplins (Maplin code: XX12N 5 a plastic container to store your ferric chloride in (I used a drinks bottle) 6 a plastic container to etch in (I used a Chinese take-away plastic box) 7 rubber gloves 8 plastic washing up bowl 9 an iron (not of the soldering type) Part 1: Printing the pcb layout The first thing you may need to do is mirror the image on your computer because you mirror it again when you iron it onto the pcb. NOTE YOU MAY OR MAY NOT NEED TO DO THIS BIT Then load up your printer with nice shiny paper (ooooh shiny) and print out your pcb layout. If it’s for a small PCB I normally put 6 or more on one sheet with a small line between them in case I screw up later. Part 2 putting the layout onto the pcb Try not to touch the printed tracks at all during this process as it can cause trouble Cut out 1 of the layouts. and soak it in water until you can peel the sheet in half. It will take less time if you scratch the side you haven’t printed anything on with a pin now you have a thin piece of soaked paper with your layout on it. Time to set up the ironing board and warm the iron up. Go get yer copper clad board (try not to touch the copper side n clean it before you do the next bit put it copper side up on the ironing board with a paper towel underneath it just to make sure you don’t get toner on the ironing board. The next important thing is that the IRON MUST NOT PRODUCE ANY STEAM because this causes the paper to bubble up. Put the soaked paper on the copper clad board toner side down and make sure its really flat with no air bubbles and iron it on (the heat settings r a pain to find and I cant remember the settings ill try to work em out later) if its too hot the toner will melt completely and become a liquid and you will smudge the print out if its not hot enough the toner wont stick down properly. You may need to iron it over several times with the edge of the iron and using a lot of pressure *(pic will come when I sort my printer out again and work out how to take the pic in another room with my webcam :-/ )* now that you think its stuck down dunk it in water again, wait till its really soaked and gently rub the remaining paper off with your thumbs. If successful you will have a mask of the layout on the copper clad board in toner. (fill in any small gaps with a cd labelling pen If it didn’t work you need to get something to remove the toner and try again L turps, meths and nail varnish remover only had limited success and I eventually had to use very fine wet and dry paper (I know you really shouldn’t but It was the only way the stuff would come off) heres an example of a board done with pen (i cant find stupid paper ) taken about 3 seconds after i put it in the acid Part 3 Etching WARNING ETCHING FLUID IS NASTY IT WILL HURT IF U GET IT ON YOUR SKIN SO WASH IT OFF QUICK IF U DO WARNING ETCHING FLUID CAN STAIN THINGS INCLUDING PLASTIC (so don’t use anything that cant go missing ) Mix up your etching acid whatever you use by the instructions on the packet. I did this by putting the acid crystals into a bottle and adding water but I also did this in the plastic washing up bowl on the wooden varnished table away from any metal wearing some rubber gloves because this stuff can be quite nasty. When you’ve finished you will have your etching fluid in a container the stuff from maplins is a redish brown with yellowy orange foam it just bodes nastyness Get your plastic etching tray and pour a bit of your acid into it (BE CAREFUL) then get your pcb and put it in the acid. For best results keep the acid moving I did this by lifting and dropping one of the sides of the plastic takeaway tin. After a few mins youll start to see areas with no copper so just wait till these areas expand to fill the areas without toner and take the board out n wash it off. Get rid of the acid by either pouring it slowly down the sink with lots of water (not recommended really) or put it in a container to use again later. the board after a few mins in the acid with some of the copper having been "eaten by the acid" the board having been fully etched Then remove the toner as described earlier cleaned board ready for use As this guide only deals with etching I wont go into drilling, tinning or soldering this seems to be quite reliable and heres a pic of my 3rd attempt with only 2 breaks in tracks Hope this helps someone again if someone tries this can they mail me pics pls EDIT: i read on a link from epanorama (i think it was from there) that u can use acid from a car battery to etch but it sounds a bit dodgy to me and the proper stuff isnt that expensive from maplin a more up to date version of this is kept on www.eaterofpies.co.uk does ne one actually read this?
Interesting method there, Nick Veys' way is similar but he does it dry - does the soak and peel work better for you? Says you can also use a photocopier to get the toner image onto shiny paper if you don't have a laser. Check out Mr Baybus 2 at the site if you like PICs
Man, that rocks. I was in maplins waiting to be served and this uni student new one of the staff, the student was saying how he got the pcb back for his beer meter and it cost him a bomb to get it done.
i tried the dry but the paper was too thick so it bubbled up and bent the paper when i either ironed it on or when i put it in water at the end to take the paper off so i worked out this way so that the paper dosent bubble up so much but ill try going through his way at some point cos theres a circuit i really want to make but i can never get it quite right my way because the diagonal tracks r too close together ant the toner tends to spread out so u end up with 1 big track instrad of about 10 smaller tracks (and the tracks r too small to just cut the gaps in using a craft knife i tried)
