Funny noise when etching alu box

[DryRoasted]

I'm at the start of a alu box etch (my first) and its making a weird fizzy noise real quiet, is this normal?  Etching pcbs (done a load) doesnt make a noise, anyone else noticed this?

[MikeH]

Depending on the etchant, aluminum etches can be more intense than copper.  The noise you're hearing is gas being released.  So.... don't breath those vapors.   

[DryRoasted]

lol so having the etch in a plastic tub next to the keyboard is a nono then?  I'm quite suprised at the speedafteronly 3-4 mins its noticable.  The reaction that causes the 'cool black lettering' effect is a handy byproduct as well.

[markm]

Some bubbling sound is normal.....sounds like Alka-Seltzer!
Don't leave it in the etchant too long though!

[DryRoasted]

thats the sound I was trying to describe!  Yeah it etches real quick

[mdh]

thats the sound I was trying to describe!  Yeah it etches real quick

You sure it wasn't the sound of Markm rubbing his hands together and quietly going, "Muahaha, muahaha!"?

[$uperpuma]

thats the sound I was trying to describe!  Yeah it etches real quick

You sure it wasn't the sound of Markm rubbing his hands together and quietly going, "Muahaha, muahaha!"?

THE EVEIL CAULDRON OF DER ETCHEN MARIEN!!!