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LAN_403

Dr. H.

Mon Mar 01 2010, 12:02AM

Registered Member #931 Joined: Mon Jul 30 2007, 05:25PM
Location: Bulgaria
Posts: 486

Good day guys

Been doing PCBs the "hard way' for more than 5 years now I've finally decided to build myself an etching tank.

It is made from 1/4 inch (6mm) plexy, has a fishtank ari pump and heater (missing on the photos) for agitating and accelerating the etching process.

Will let the glue dry overnight and test it for leaks tomorrow.

Cheers

Killa-X

Mon Mar 01 2010, 12:29AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Looks good! Seen many tanks online, One person used an air-intake at the bottom and fed in air to etch, that way all the many bubbles would agitated it.

Hope the tests come through good )

Finn Hammer

Mon Mar 01 2010, 06:17AM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

Looks good,

I see you learned at least 2 things in the stinking desert:
1.use acrylic
2.keep workspace tidy

Cheers, Finn Hammer

Dr. H.

Wed Mar 03 2010, 07:01AM

Registered Member #931 Joined: Mon Jul 30 2007, 05:25PM
Location: Bulgaria
Posts: 486

Hi guys

I've filled it up with water - not a single leak. The bubbler is work OK. The only thing is that it takes about hour and a half for the heater to heat up the solution ... ohh well ... will just have to switch it earlier

Finn Hammer wrote ...

I see you learned at least 2 things in the stinking desert:
1.use acrylic
2.keep workspace tidy

Hee hee - I sure liked being there

P.S. Sorry for the bad quallity pic.

Cheers

Dr. Drone

Wed Mar 03 2010, 04:39PM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
Location:
Posts: 1673

Dr. H.

Wed Mar 03 2010, 09:26PM

Registered Member #931 Joined: Mon Jul 30 2007, 05:25PM
Location: Bulgaria
Posts: 486

Hi sir

Dr. Spark wrote ...

Nice tank, only issue I see is no blue LEDâ€™s.

I doubt those will accelerate the etching speed

I was actually thinking of putting a few LED but don't have low voltage supply on the tank.

Cheers

ragnar

Wed Mar 03 2010, 09:35PM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

Dr. H. wrote ...

I was actually thinking of putting a few LED but don't have low voltage supply on the tank.

If the heating element is within the tank, there's a big resistive divider and should be able to choose any suitable tap; no excuses now... :P

Dr. H.

Thu Mar 04 2010, 09:56AM

Registered Member #931 Joined: Mon Jul 30 2007, 05:25PM
Location: Bulgaria
Posts: 486

Darn ... you got me .....

shoud I risk electrocution for few LEDs .... CERTAINLY

Have a great day guys

Conundrum

Sat Mar 06 2010, 03:50PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

I am also building my own etching tank using recycled glass harvested from dead HP printers.

the cool part is that the volume of etchant is minimal and am also using a peristaltic pump kludged from a spare fan motor and Polymorph, as well as some aquarium tubing.

In restrospect, maybe I should have made some glass end plates and siliconed those, as there is a taper on the glass now.

has anyone managed to integrate an ultrasonic cleaner into an etching tank? this would be an effective way to rinse a board while ensuring that any remaining etchant was flushed away before it causes corrosion.

fwiw make sure you leave it long enough to get rid of the vinegar fumes, as they eat copper right through the resist. Don't ask :)

EDIT: It no longer leaks :) I have left it for a day and seems fine.

I did have a thought a while ago about a "one step" laser etcher and processor, that exposes the PCB through the glass (would require some innovative pumping however) so the process would be expose, develop PCB (maybe combine the two if silicate is used), then flush out developer when complete , etch then flush/agitate with water.
the main reason for integrating the two steps is that the presence of an air gap does nasty things to the board, my inspiration is the use of water when doing uv pcb exposure to hold the acetate in place by surface tension..

For various reasons it might be easier to run the setup horizontally, then use alignment marks for the software to correctly index the board.

Sound possible?

-A
"Bother" said Pooh, as he flashed his BIOS with W32.Nimda...

Dr. H.

Sun Mar 28 2010, 07:19PM

Registered Member #931 Joined: Mon Jul 30 2007, 05:25PM
Location: Bulgaria
Posts: 486

Good day guys

Conundrum - glad to hear your tank is coming together

also you've got a pretty interesting idea.

Some info - today I've finally tested the tank. Filled it with 2.5 liters of solution (sodium persulfate) and placed the boards. It took about 7 minutes to etched them at fairly cold solution (about 26 deg C - it was pretty cold outside (around 8C )). I've etched a total of 6 quite big boards and it is working PERFECTLY - much faster and cleaner than with the FeCl3. Also the qullity of the traces is much better and the permenent marker stands better - maybe because it dosn't have enough time to desolv.

All in all - I am REALLY HAPPY with the result

Will *never* use FeCl3 again.

Cheers

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