I'm looking to etch my first PCB soon and I have bought some FeCl from maplin in a powder/crystal form.
It says that it will make 0.5l of solution. Shall I mix the whole batch together and store it in a plastic bottle for later use, or should I mix only enough for what I need to use at the time? I plan to use a tupperware box to etch in. I read somewhere that the crystals can give off quite a bit of heat when mixed/ re-hydrated. Any tips? Should I use boiling water to mix them with or use cold water and stand the tupperware tub in a bath of hot water to speed etching?
I'd mix with warm water. And I don't see any reason not to mix the whole batch. BUT!!- remember; ALWAYS add the acid to the water; pouring the water into the acid will cause some pretty exciting, but bad, things to happen.
I don't intend to steal this topic but while you're at it:
Hey, out here where I live I haven't been able to locate any solution form of ferric chloride whatsoever, and all I can get are these weird grains that you're supposed to dissolve into water. Does anyone know what's the concentration supposed to be? I'm thinking I put too little of the grains into water because the etching is so devilishly slow, but I don't want to use more than is needed, either.
Here's a picture: http://www.partco.biz/verkkokauppa/images/tuotekuvat/f/ferrikloridi-large.jpg
I mix mine in batches (just enough for however many boards I will do) and use a 60W light bulb over the top to keep it warm. Also, agitating and etching with the board suspended face down in the solution will help. I mix into warm water and just kind of estimate (e.g. use about half the powder in about .25l of water). It has worked well for me thus far.
Hi,
I too have the powder from Maplins.
I mixed half my powder into half the amount of warm water. From memory I think I used about 50ml water.
I keep mine in an old medicine bottle (washed thoroughly...), and simply pour our as much as is needed into a small plastic tub (from an Indian Takeaway, would you believe).
I keep *this* tub warm during etching by floating it on a larger tub of hot water, but have also been known to put the takeaway tub on a USB cup-warmer - which also does the job.
Good luck with your etching, I'm sure you'll get the hang of it.
p.s. Warming your boards before immersion can also help. I leave mine on a radiator (flat, face down) for 10 minutes or so while I prepare the etching bath.
Quote from: newfish on March 06, 2009, 04:48:45 AM
I keep mine in an old medicine bottle (washed thoroughly...), and simply pour our as much as is needed into a small plastic tub (from an Indian Takeaway, would you believe).
The spice residue helps speed up the etching. Sometimes I just order the extra-extra spicy curry and etch my boards in that :icon_wink:
The spices add extra Mojo.
...seriously...
:icon_razz:
Rapid sell a 'safe' etching system. All it comprises is a long, plastic bag, some clips to isolate the board from the etchant at various stages, and etchant. Might seem a bit of a rip-off for the money, but the etchant seems to be a lot better than the stuff that Maplin sell (and everyone else - it's all made by the same manufacturer). The etchant that comes with the kit looks different (it's lighter) and appears to be more efficient: I've etched using bags for a while, but the Rapid stuff does the job quicker.
Just thought I'd mention it.
Tape "handles" as in this picture make it easy to follow the etching process.
http://web.telia.com/~u85920178/data/pcb-etch1.jpg
By occasionally lifting the pcb up you can see when it is ready. Occasional lifting also breaks possible air bubbles under the board. Bubbles can leave round, un-etched areas.
i mix mine per batch at about 1:3 powder to water ratio, then put on rubber gloves and rub it in the etch with a sponge. sometimes i'll let it soak a bit before the rub, but this speeds up etching profusely. it seems as if you can rub the copper right off once it's been soaking a bit.