Etch tank

Get a small fish aquarium to use as an etch tank. Big enough to place your biggest PCB into it. This one is 8"x5". Also get some air tubing and suckers to hold the tubing to the base of the tank.
You can get a small air pump, as displayed, or get a bigger one...More power, more bubbles. :-)
Heat one end the the air tubing with an open flame and then seal it using pliers.
This is what is looks like after it is sealed.
Using a fine sewing needle make holes in the tubing towards the sealed end. If holes are big, the bubbles will be big, I prefer many smaller holes and finer bubbles. Make holes the length of the tank.
Use the sucker the hold the tubing do the base of the tank.
I made a cover from cardboard and made a hole for tubing to fit thru. the board was cut at the back about 2" and rejoined using masking tape.
The cover is more of a protection from the bubbles splashes escaping the tank and staining anything around it.
Use water to test the tubing, once satisfied the the bubbles, (size of bubbles and the length of tubing where the bubbles released), drain water and replace with Ferric Chloride.

 

The tank is use to speed up the etching process. I tape a length of string one the back of the PCB and let it float on the etching solution. You will know it is done when you can see the PCB design  Refer to my older post.

I stopped using the air stone as it does not last and disintegrates over time.  You can also purchase from fish shops air tube that produces fine bubbles. Where is the fun in homebrewing in doing that... :)