How to heat up PCB etchant?

[Phil Mcintyre]

I've seen people mention that they use aquarium heaters for heating ferric chloride/pcb etchant. The ones I've looked have thermostats that stop at about 35 degrees, but the etchant instructions say it must be at about 45 - 50 degrees for the ones I've used. I'm fine when I first use it, I can just make up the solution with hot tap water... It's when I leave it and want to come back to it later that I'm having problems, and it seems a waste to make a new batch up every time.

So how does everyone else do it?

Also, something related.. I saw this http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=80010&CTL_CAT_CODE=&STK_PROD_CODE=M66683&XPAGENO=1
today, and immediately thought PCB etching tank!

Cheers
Phil

 

[BYacey]

Aquarium heaters have a knob on top that adjusts a pair of bimetal contacts. This knob usually has a stop so it cannot be adjusted too high and cook the fish. Simply remove the plastic stop or whatever method they use to limit this and it will run hotter.

 

[Guest]

Maybe it's me being lazy - but I just bung the plastic container into a bigger one that has hot water from the kettle in it

 

[yan_b]

i always makes very small amount of acid just enough to process the circuit , and to keep the small amount hot for long time i use two bowls one in the other , the lower containg large amout of hot water, the other floats and conatind the small amout of acid, this speed thing up for at least halfe the useal time.

oops double post. :roll:

 

[peterc]

There is a very nice, all-in-one etching kit courtesy of our hosts here:

http://www.groupdiy.com/detail.aspx?ID=316

Peter

 

[Kev]

I don't heat up the etchant ... per-say

I mix up just the right amount of etchant for the job and use hot water and let it cool during the process.

Sometimes I just use hot tap water
AND
sometimes I do use the kettle
BUT I always mix in some cold water to start with as the plastic tank I use and boiling water don't agree with each other and the first tank didn't survive.
:shock:
live and learn.

If you use a glass tank, then I don't see any problem and freshly boiled water might be good.

 

[mnats]

I always just use an old microwave - the advantage being that you can heat up a burrito at the same time :razz:

 

[Emperor-TK]

Revenge of the iron burrito....

 

[EZ81]

A €11.95 aquarium heater works fine for me. As it is a cheap model, it has no temperature limit built in and does stable 55°C (and more, which i have not tried) without problems. With 100W, heating 1.2l of etchant takes forever, though, so if you go this route, get the biggest model available (**insert tool time grunt here**) :twisted:

;Matthias

 

[dale116dot7]

I use an aquarium heater with the thermostat bypassed and an industrial temperature PID controller with a stainless-steel thermocouple in the fluid. It's overkill but it'll maintain 55 degrees C easily, and exactly.