ferric chloride removes forge scale?

[J.Leon_Szesny 13]

hoi! 
working on some knives with a forge scale finish section and I want to keep that part on, been thinking of getting some ferric chloride to quickly get the contrasts between the 2 steels to show up.
does it dissolve scale? cause I know vinegar do.

I got 1 jap stone, thats good but...not enough to really bring out the contrast and they be expensive...like an arm or a leg!

[Alan Longmire 2,633]

It doesn't really do a lot to forge scale if diluted the way we usually use it, 3 or 4 to one with distilled water.  You might have a hard time neutralizing it because of all the little pits in the scale.  I'd just carefully wipe some on the polished part and see what happens.

[J.Leon_Szesny 13]

neato!
cause I do a lot of forge work with scale finish, 
I had read that ferric chloride had, hydrochloric acid in it, which I understood as a powered up version of vinegar.
gonna buy me a bottle or a powder box!
thx

Edited November 24, 2020 by J.Leon_Szesny

[Charles dP 458]

Acetic acid is what you are thinking off when you refer to vinegar (4-18% acetic acid). Hydrochloric acid is much stronger still. Hydrochloric acid is used to make ferric chloride but there shouldn’t be any of it left in the solution once you have made the ferric chloride.

[Daniel W 82]

In keeping the scale on, you can paint a resist on the forge scale. Anything based with lacquer, clear nail polish etc. may not leave the finish your looking for matte clear rust-o-ilium paint may work.  Sharpy marker works to a point.

 

I've not tried it, but just simple wax may also work, and might be the best way to go if you can test it out. In this way, even if you wipe on the acid, it will not get to the rough texture of the scale. 

 

There is a number of different acids you can use, the ferric chloride is a general what works best. I've used muriatic acid with not steel, and it is an instant etch. Stinks, and if left more than a few seconds without neutralizing it, makes a really weird brown patina. *NOTE* muriatic acid is really strong in comparison to ferric chloride handle with care! If anyone gets an idea out there.

[Pieter-Paul Derks 206]

In my experience the forge finish holds up just fine in ferric chloride, for some reason it doesn't eat scale like vinegar does.

 

I also like ferric in that it isn't dangerous like the other acids, it does leave horrible orange stains if you spill it though.