Microwave to heat ferric chloride???

[Pushtone]

I have an old microwave oven in the garage. Still works. 

Would it be unsafe to heat up ferric chloride in a microwave before etching? 

Doesn't need to get boiling hot, just warm. 

30 seconds ought to do it eh? 

[choklitlove]

try it and let us know.



don't die.

[Pushtone]

I'm guilty of posting before searching.

Found answer here if your still interested. 

http://www.diystompboxes.com/smfforum/index.php?topic=27682.0

An excellent thread started by Paul Marossy on etching techniques.

[choklitlove]

cool, you're still alive and so am i!

[Connoisseur of Distortion]

so, it's safe if you never want to use that microwave again? i am a bit lost.

[RaceDriver205]

try it and let us know.



don't die.

LOL! 

[TELEFUNKON]

?
I don`t have a microwave oven, and have never used one.
Absolutely no clue, whatsoever.

Wondering however, if a MW could be used to preheat a PCB
or an aluminum box for a couple of seconds to get on temperature
for iron-on layout/design purposes (PnP).
?

anyone got experience or knowledge?

[Paul Perry (Frostwave)]

I wouldn't heat ferric chloride in a microwave.
Because, I think there is hydrochloric acid formed by hydrolysis in the mix, and maybe some of this will evaporate out & corrode the insides of the microwave. So it will wreck it in short order, I expect.
It's a while since I was near ferric chloride solution.. does it SMELL acid?? if so, I wouldn't heat it in the oven.

[Ge_Whiz]

I would not heat either ferric chloride or metal in a microwave oven. Fumes from the ferric chloride will almost certainly corrode the inside of the oven, including, possibly, the microwave seals causing microwave leakage. Hot spots in the liquid (especially if you re-heat old etch) can cause superheating, leading to a faceful if you're unlucky. Obviously, you can't just say "30s is safe" because it depends on the power of the oven and the amount of etchant.

Placing metal in a microwave causes arcing. This will damage a metal surface, and probably rip tracks up (possibly invisibly) on a PCB. It's also a serious abuse of the magnetron.

[Mark Hammer]

I will repeat this until I'm blue in the face.  The only etchant that NEEDS to be heated is that within a short distance and immediately in contact with the board itself.  Heating up the entire etchant bath is simply ONE WAY to accomplish that but it is not required.  You can also point a hair dryer or heat gun at the back of a board that's floating on top of the etchant. or use one of those long-neck halogen study lamps with the bulb pointed down at the PCB from a few inches away.  If the board itself is made warm, then the etchant in immediate contact with it will be warm.  Floating the board at the top of the etchant bath (copper side down, obviously) exposes one side of the board so that it may be easily heated across its entire surface.

If you are desparate to have a warm board, then use the iron employed to put the PCB transfer on to warm up the board before putting it in the etchant.

METAL THINGS DO NOT BELONG IN A MICROWAVE!!!

[R.G.]

Would it be unsafe to heat up ferric chloride in a microwave before etching?

Bad idea, for some of the reasons mentioned here.

It's much simpler to use a home improvements store heat lamp in a clamp-on reflector bulb fitting to heat an open tray. Safer too.

I used to warm up my plastic bottles of etchant by standing them in a sink of hot tap water for 10-15 minutes while I readied all the other paraphernalia.

[TELEFUNKON]

OK - after first warnings, I googled a bit
and will stay away from microwaves.

Wouldn`t wanna blow the yellow stuff around (in the kitchen?)
with a hairdryer, though.

[Mark Hammer]

Well, you are wise to avoid anything that risks spillage or splattering.  Ferric Chloride is the HIV, avian flu, and hepatitis C of chemicals, rolled into one.  Once you get it on clothing, it's there for life, and it spreads to other things.  Stick a t-shirt with a little bit of FeCl stain in the washer and everything soon has a stain.  Seriously.

Having said that, as liquids go, ferric chloride is fairly heavy, and VERY heavy if it is somewhat used (the copper doesn't magically leave town; it gets added to the weight of the fluid).  If your etchant is sitting in a container whose sides come up at least an inch higher than the fluid level, and the hair dryer/heat-gun is anything less than wind-tunnel force, you should have little problem with splatter if the heat source is at least 2-3 inches back from the board.

All in all, the biggest and best reason for using a lamp as a source of heat rather than a hair dryer is the fact that you can turn the lamp on and walk away.  The heat blowing methods require you to stand there like an idiot for 10 minutes holding a hair dryer while your wrist goes numb.  The very same wrist you will need for drilling and soldering later that day.

[toneman]

a small note:
AC -powered hair driers & water *DO NOT* go together!!   
Even if U are running from a GFI outlet.
I *have* used the microwave "heating technique" after the idea was posted on
this forum a year or so ago.....
It *does* work!!!  U *DO* have to be carefull!!   
It enabled me to reuse some FeCl that I knew had some life still in it.
Since then, i've been looking for a used microwave at Goodwill.
I just dedicated a large square tupperware container for my "reheater".
U put metal in microwaves to do browning & bacon crisping.
If U put a spoon, for example, in the m-wave, it will give off sparks.
A dish with any metal in/on it (i.e. gold), might spark or will get warmer than a pure plastic dish.
If this is your *first* or actually *2nd* time working with FeCL, i would recommend the hot water bath for reuse.
I was skeptical, at first, about how this would work, but i did it, and it does work.   
I definitely do not like the proposed hair drier technique.   
Leave the FeCL in a clear glass or plastic container in the sun for a while.
U can feel the sides to tell how hot it is.  Swirl it around as it heats up. 
Use an infrared therm to do noncontact measurement.
U can only do this in the summer as winter time air defeats your intentions.
Always!!  play it safe---gloves--latex or nitrile, & saftey glasses & work outdoors.
guess that was a big, small note   

[Ponchus]

I simply put ferric chloride into a plastic container and throw the PCB into it. Then, I fill up a separate (slightly larger) plastic container with boiling water (or very hot tap water) and float the container with the etchant on the boiling water. Lately, I've taken to putting a weight on top of the etchant container, so that it gets pushed into the hot water, rather than just floating on it. Every so often, I replace the hot water. Seems to work fine for me...

[Pushtone]

Thanks for all the advice and words of wisdom.

But I think I've found a better way. I have an old electric teapot. Its heating element is designed to be immersed. It could boil the solution but I have a meat thermometer to prevent that. Maybe I can mod it to only get hot and not boil.

Anyway I need a way to heat the ferric chloride because I have to etch far away from AC or a sink. And this is all about etching artwork into Hammond boxes. My tests indicate to me that a hot solution produces cleaner lines. Still testing.

[Peter Snowberg]

But I think I've found a better way. I have an old electric teapot. Its heating element is designed to be immersed. It could boil the solution but I have a meat thermometer to prevent that. Maybe I can mod it to only get hot and not boil.

The ferric chloride will etch away tthe element casing and then you'll have AC energized etchant and an electrical hazard.

They're desiged to be immersed in water not ETCHANT!

[brad]

Yikes dude.  Don't worry so much about heating your etch solution.  Just placing the containter in a larger one with a bit of warm water in the bottom of it will do the trick.

[Pushtone]

Oops, Right, FeCL eats metal...

Back to the microwave.

Please try to understand brad. This is a totally different type of etching than doing a PCB. I've had to re-learn techniques.
Really hot etchant applied with a paint brush, washed off and reapplied several times makes nice fine lines in the aluminum.

The results speak for themselves.

But I think I've found a better way. I have an old electric teapot. Its heating element is designed to be immersed. It could boil the solution but I have a meat thermometer to prevent that. Maybe I can mod it to only get hot and not boil.

The ferric chloride will etch away the element casing and then you'll have AC energized etchant and an electrical hazard.

They're desiged to be immersed in water not ETCHANT!

[sta63bmx]

That box is just excellent.  After it was applied, did you let it sit and etch for a little bit and then wipe it off, and repeat?  How long in between "coats"?