I've been etching my own prototype boards for many years in a glass tray, using a griddle to heat the solution. The large horizontal area of the solution resulted in lots of fumes that were hard to avoid breathing. The boards etched unevenly (due to hotspots of the griddle) and required a lot of hand agitation (and breathing the awful acid fumes).
I decided to make a vertical etching tray with self-contained heating (aquarium heater) and agitation (aquarium aerator). As I prefer using HCl/Peroxide solution for etching, the air bubbles replenish the solution in addition to agitating it while etching. And the small surface area makes it easy to evacuate the air above it to outside.
- Small footprint, perfect for the hobbyist with a small workshop
- Fast, even etching due to better heating and agitation
- Less fumes due to smaller area during storage
- Easier to vent due to small opening on top
- Looks and sounds really cool
Safety - READ THIS AND BE SAFE
Working with toxic chemicals requires care. Always use proper precautions. Make sure the container cannot be tipped over by securing it to a wall or a properly built base. Always use appropriate ventilation equipment and do not breathe fumes from the etching solution. Use nitrile gloves rated for your chemistry.
Keep the work area dry, especially around electric outlets and extension cords. Keep the air pump and tubing in a safe dry place, preferably above the water level to avoid any possibility of siphoning the caustic solution out of the tank!
Use common sense, and remember that accidents are painful, expensive and generally preventable.
Cost and complexity
This is an easy build. It should cost well under $50 to procure the parts. It took me about an hour to put it together.
Step 1: Procure Parts
Find a suitable container
I found a perfect glass container at the local Safeway flower area. It is a flower vase, about 11" by 2", deep enough for my small boards. Look for a flat container to avoid having to fill it with gallons of etching solution.
-Pick a glass aquarium heater that fits into your vase. It should be immersed almost completely.
-Get a small air pump for aerating aquariums. A really small one will do.
-Make sure you have enough transparent tubing for your setup.
Also, get some scrap plexy (1/8" -1/4") to make a lid.