The thought occured to me the other day. It's caustic at least, (not sure if it's acidic?) and fairly cheap/available. Anyone ever try etching with it?

 

Any idea what the active ingredient is, or the Ph? How much should it be diluted? Would coating with whiteout or wax be good enough to etch patterns into steel? Or would it eat the whiteout/wax right off? (I'm sure you guys are familiar with the process of coating steel in whiteout or wax, scratching words, patterns, etc with a small tool and the acid etches where you scratched it off)

 

Would like to find out before trying it, in case it ends up being unsafe. If no one knows on here I guess I'll try to do a bit more research.

If brake fluid etched steel it would eat steel tube brake lines...... :mellow:

In another life I was an GM tech, and the reason that it eats up break lines and such is it loves water. Dot3 and Dot4 should be changed once a year under hard service (city driving) to prevent the build up of corrosive compounds. As to it eating paint, it is a petroleum oil, similar to paint thiner.

I suppose that's true. Could it be used to etch copper or brass then somehow?

Cheapest/Easiest way is to use common houshold vinegar.

Aqua Regia is the echant I'm familiar with, but be carefull as it will etch gold and you with equal veracity.
As to etching copper and brass, they are much more resistant to corrosion than carbon steel.
My experience (and education) leads me to believe that break fluid is not going to make an etchant'and it is hit and mis as a paint stripper.

Break fluid is dangerous stuff.  Inhaled it can cause brain and lung damage.  I can only think that used as an etchant it would not be very good. 

Thanks for all the answers. Though I wouldn't be too worried about inhalation, as I have a fairly well ventilated area and a legit gas mask (It works well, I've used it to avoid fumes from paint and cleaning chemicals) Guess I'll just stick with warm/hot vinegar, though I've toyed with the idea of using something like lemon juice, which (I think) is a bit more acidic than vinegar.

Don't forget that protective mask filters are a consumable. Some have a life time that starts as soon as you open the package, others as soon as you expose them to what ever they are intended to protect you from and others have a total exposer time. They are also very specific as to what they protect against, and will offer little or know protection against other substances and/ or break down very rapidly.
If you have a military protective mask, or a firefighters protective mask, they are very robust and protect against a large number of hazards, but may fail in as little as 30 minutes depending on what they are exposed to.
Industrial masks work very well, and filters are readily sourced, multi hazard filters are very expensive. Protective masks take maintenance, as the valve diagrams, straps and filters all wear out.
Talk to a industrial safety house as to use, fitting, adjusting and maintenance. As to military masks, the manufacture and or a military NBC specialist are who to talk to.