For a while now I have been wanting to build my own PCB etch tank because I was a tad fed up messing on with a tray of etchant. Somehow I always seemed to get it everywhere and stain everything in sight. This is my first instructable, so please forgive the inevitable sucky-ness. Apologies for my pictures appearing mid-way through the build. I forgot to start snapping photos from the beginning. I shall also include a link to the videos on my youtube channel.

For this build, I used the following items/materials:
> 1x silly named plastic food storage jar from Ikea (pack of 3 for £5-ish)
> 1x unbranded aquarium air pump, including 3m silicone airline, non-return valve and diffuser stone (ebay at £5 inc postage).
> 1x 6mm airline diffuser kit (£2.99 from local pet shop)
> 2x Flow control valves (£0.80 each from local pet shop)
> Sugru - my most favourite thing in the world!
> Green food colouring (to add to water during first pump test run)

Tools involved in build:
> Bench drill w/4mm HSS drill bit
> Elbow grease
> Time

Step 1: Time to Drill!

To start, I marked on the bottom of the jar where I would like my inlet and outlet valves to go. To ensure the hole is going to be the correct size, I measured the outer diameter of the valve port with a set of digital callipers.

For these parts, I needed a 4mm drill bit. So, once I marked the jar with my trusty sharpie I began to drill. (apologies again for lack of photos, I really should have started snapping sooner). I drilled slowly and carefully to ensure that I did not slip or mank up the plastic, as I hate faffing around trying to clean up plastic once it has been messed up.

Step 2: Stuff the Valves in and Apply Copious Amounts of Sugru.

Ok, I keed I keed! I carefully inserted the valves and applied an appropriate amount of Sugru - which was allowed to cure for 24 hours before testing. I love Sugru... so much nicer than using the original silicone sealant yucky stuff that I had originally planned to use.

As you can probably see by the pictures, I attached the inner pipe, non-return valve and inner diffuser tube prior to applying the Sugru. This was just to make things a tad easier in the long run.

Step 3: Adjust and Fix Diffuser Tube Position

At this point I now started to try and figure out the best position to place the suction cups that came with the diffuser tubing. Although it may look a bit messy in the picture, this configuration worked better than when I placed the tube neater. Once the tubing position has been set.... time for the first test to make sure everything is working....

Step 4: Test Run!

So... the time to perform a test with liquid has arrived. Instead of jumping straight to the chemicals, I decided to test with water and a few drops of green food colouring to make it easier to see in the pipes and tank.

Fingers crossed.... *power on*

http://www.youtube.com/watch?v=-4PhwMVDDg8&hd=1

As you may have seen, it seemed to perform quite adequately for the purpose it was intended for. The only slight problem (not caught on camera) was that there was a tiiiiiny leak coming from the outlet valve. This was not a major problem to fix, I just removed the sugru and re-applied some more. I should have taken a bit more care at first when inserting the valves - I did not ensure that it was stuck down as well as it needed to be. I have since tested it again with the newly sealed valve and it functions fantastically.

Step 5: To Be Continued...

That's all for now - once I get a chance to do some actual etching I'll add a new video and some pics no doubt. Bring on the real chemicals!

Any feedback at all is welcomed - either regarding the build, or this instructables post as this is my first time.