How much etchant

Thread Starter


Joined Jan 1, 2009
I've looked through this thread which was really useful.

I used to buy it pre-mixed, I remember it was dark green in translucent plastic white bottles.

Now I have bought a bag of 250g of pellets that's meant to make up 500ml of solution, but at first I only want to etch a small single sided board. How much do you think I should mix up?

Should I mix the lot and store it or mix it in small batches? What's the smallest practicle size to mix?

A few days later I may want to make 2 or 3 more similar sized boards.


Joined Mar 24, 2008
An old trick I use for FeCl is to wrap a paper towel around the seal, and thoroughly tape it in place. I have a bottle that I use occasionally, it is more than a decade old. Whenever I open it I just change the paper towel for a new one, the old one is usually crusty and brittle. The reason I do this is the fumes get out from the FeCl and corrode anything metal that might be next to it.