Can anyone tell me if it's worthwhile/possible to keep a ferric chloride solution to do more etching.
Unless you're doing something really touchy you can keep using it till it wont etch any more, but it gets really scummy. When its on its way out you'll notice the time it takes to etch a PCB will take longer and longer.
Remember to keep the solution in something non-metallic (that includes the lid). I stuck some in a jam jar at one point to find the next day there was no lid left after it had tipped over... Once you make your solution, it should last up to 6 months, but obviously the more you etch, the less effective the solution becomes in the future.
OK, i'll try and find something suitable to store it in as it looks like i'll need gallons. First time i've tried this and not having much success as i've made 8 small boards and none of them are useable. Doing it the UV way and wasted 4 boards getting exposure time correct and the next 4 have what looks like a finger mark that was not exposed but it's in a different place each time i etch them. I've tried to keep everythig clean but this random blotch keeps appearing on the boards.Anyone any ideas as this is expensive and takes a lot of time with the hacksaw. I'm using that Seno photo-resist on a well cleaned copper board to make them.
ohh... spary on photoresist... if this is your first time, try with presensitised board as it is alot easier to get used to, then go onto spray sensitising after that! did you make your UV exposure box or buy it? I am having a darkstrip issue with mine ATM so your issue may be a similar issue.. Sorry not much help but it took me about 8 boards to get it right, and my siccess was last night... proper transparantsies.. OH, make sure there are no fingermaks on them as itll show too! good luck!
"ohh... spary on photoresist... if this is your first time, try with presensitised board as it is alot easier to get used to, then go onto spray sensitising after that! did you make your UV exposure box or buy it?" The photoresist stuff i'm using comes in a small container with a foam application pad on the end and can end up quite streaky and thick in places.I made a lightbox with an old scanner I had and a large flykiller i bought and it's got 2no. 15w 300mm uv tubes and works fine. I ordered some presensitised board today as i'm really cheesed off as I made another 6 failed boards today. The developer comes in the same type of tube and you dab the wet foam pad onto the exposed board and wash it off and it don't seem to be much good. The trouble i'm having now is the etcher is eating into the copper tracks before the surplus copper is removed from between the tracks. I cut and copied from your post as I don't know how to put quotes in.
dab on developer? oh no, you need to immerse the board into the developer for about 45seconds, during whihc time the design should show up clearly , then wash then etch. i cant see dabbing on being much affective.. besides, its a strong alkali and iritant... Edit: try using rapidselectronics eco photoresist board and their developer, thats what i use and it works pretty well!
I've been making more or less perfect PCBs for a while now, after a lot of trial and error. Here's what I use: - Pre-sensitised copper clad board - http://maplin.co.uk/Module.aspx?ModuleNo=2033&TabID=1&source=15&WorldID=&doy=3m11 - Sodium persulphate based etch powder - http://maplin.co.uk/Module.aspx?ModuleNo=17355&TabID=1&source=15&WorldID=&doy=3m11 - Caustic soda (NaOH), from Boots Follow all the instructions on those Maplin pages for etching and exposure times. To start off with, print the circuit design onto some acetate. Using a UV lightbox, expose the copper board to the UV light for around 10 minutes. After the 10 minutes, develop it in the NaOH solution, dry, and etch. Perfect results every time. Whenever I started off with copper board that I had to apply photoresist to, the results have never been good.
Solved problem. Thanks for replies,I have already ordered sensitised boards and will use normal method in future.I tried this method as I thought I might have a few failures and this would be cheaper while learning. Been using special coated Epson film for inkjet and printing mirror image so as copper is against ink when exposing and that part of the procedure was perfect.All the tubes of chemicals in this method use foam pads to dispense the various liquids and if used correctly it works ok.Discovered the problems I was having were caused by me using the wrong developer because they supply two different types and I of course was using wrong one and it was allowing the etching fluid to remove ALL copper from the board.I have ordered correct developer and should be making perfect boards tomorrow.
Got the new developer and it didn't work either and I ended up having made in total eighteen useless boards.When I got over my depression I ordered pre-sensitised boards,developer and sodium persulphate as suggested and when they arrived I made a perfect PCB first time in less than 15mins.The first method seemed like a good idea as you didn't have to mix chemicals or use trays but I just couldn't get it to work and it turned out to be an expensive failure because of all the stuff I wasted. Will use normal method in future.
