[sdiy] uh-oh..etchant saftey???

[Matthew Smith]

Quoth Ray Wilson at 2009-03-30 04:30...
> The main nasty ingredient in ferric choloride is hydrochloric acid. It is 
> the checmical that gives the solution it's bite. I have breathed ALOT of 
> ferric chloride (in solution with water) fumes it over my life (the powder 
> will eat your lings, avoid breathing it at all costs) and I'm still here. 
> Short exposure to fumes leaking from a spent bottle will probably not do 
> permanent (if any) damage. I believe no damage actually.
...

It's yucky stuff, eats cotton fabrics as well if it touches them.

I used to use ferric chloride for etching.  Could never see through it
to tell what was going on, stained like you wouldn't believe - so never
again.

I've changed my chemistry completely - using sodium metasilicate for
developing (far less fierce than sodium hydroxide which can overdevelop
very easily if too concentrated, warm, etc) and ammonium persulphate for
etching - far less nasty.

As it happens, I made 4 boards (sorry, not SDIY related) yesterday -
first time using my new Kinsten bubble etch tank.  SO much easier than a
rocker dish!

So, from a hazard point of view, none of these are nice (but not
terrible), all should be kept away from children (and pets) but then
again there are worse things in the house such as hypochlorite bleaches,
caustic soda (sodium hydroxide), etc.  And there's no way that etching
chemicals would be making a burning plastic smell.

If in a single-storey house, check the roofspace for the source of the
smell.  I'd be worried about ANY burning smells in case they are a fire
in the making.

Cheers

M

-- 
Matthew Smith
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