Homebrew PCB Etch Tank

by FjerrFjerrson in Workshop > Tools

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Homebrew PCB Etch Tank

first_test_run.jpg
basic parts needed.jpg
nectar of the gods.jpg
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

Time to Drill!

drill.jpg
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.

Stuff the Valves in and Apply Copious Amounts of Sugru.

nectar of the gods.jpg
outlet valve.jpg
inlet valve.jpg
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.

Adjust and Fix Diffuser Tube Position

airline diffuser and check valve.jpg
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....

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.

To Be Continued...

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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.