When removing rust from old axes...

[Moonw]

...that you intend to use...did you find hydrogen embrittlement to be a concern in practice?

Per my understanding, this process will take place no matter whether using acid or electrolysis.

For lighter rust, I am tempted to simply try WD 40 or a coat of Rennaisance Metal Decorroder. I may be overthinking this. I'd like, on one hand, to know how much life (hardened steel) is left in an old axe, so acids would be preffered, but, OTOH, I'd rather not weaken the steel.

Any thoughts? Btw - for a total beginner in old axe restoration?

 

[Jens Schuetz]

I used it on a knife only and it didn't seem more brittle than before.
Given how electrical charges flow I doubt that embrittlement will go below the surface very much at all.
Most vulnerable should be the thin edge.
If there is any effect at all it should be gone with one sharpening.

 

[Hickory n steel]

If I were you I'd just learn what a full bit should look like ( usually if it's not too round it's likely fine)
Because using electrolysis or vinegar ruins the patina which is the history and identity of the axe.

on an axe head that wasn't in the ground ( really badly rusted and pitted ) you should just remove the rust with a wire wheel.

 

[300Six]

Wire wheel in a drill is one way of doing this and a twisted wire cup wheel on an angle grinder is even faster. Or you can go nuts with scouring pads and steel wool if you want to do this slowly and entirely by hand.

 

[FortyTwoBlades]

Based on my findings, hydrogen embrittlement is really only a concern if you're really putting the juice to it (which you shouldn't be) and it wears off as the hydrogen outgasses from the metal. If you really wanted to be obsessively careful you could speed up that process by baking it out, but the kind of embrittlement that you see written about is usually in reference to high-strain/repetitive fatigue structural or mechanical components where the forces involved are much greater than those of a hand tool and/or involving processes that cause a much more severe degree of hydrogen deposition. Springs are seemingly the sort of object most affected by hydrogen embrittlement due to their thin cross sections and repetitive experienced strain. Axes, not so much. As Jens noted, any embrittled steel likely to fail would be right along the very very edge, and would be removed the first time you sharpened it.

 

[Moonw]

I used it on a knife only and it didn't seem more brittle than before.
Given how electrical charges flow I doubt that embrittlement will go below the surface very much at all.
Most vulnerable should be the thin edge.
If there is any effect at all it should be gone with one sharpening.

Thanks. This makes sense.

 

[Moonw]

If I were you I'd just learn what a full bit should look like ( usually if it's not too round it's likely fine)
Because using electrolysis or vinegar ruins the patina which is the history and identity of the axe.

on an axe head that wasn't in the ground ( really badly rusted and pitted ) you should just remove the rust with a wire wheel.

Good point in the patina - for historical and practical purposes I'd keep it. Luckily for me, this old head I picked up from a pile of rusty tools is in a very good shape. The bit seems fine (although it looks to be some European pattern, may be Romanian?) All in all, it looks like a well-cared tool that wasn't abused in any way. Thanks.

 

[Moonw]

Wire wheel in a drill is one way of doing this and a twisted wire cup wheel on an angle grinder is even faster. Or you can go nuts with scouring pads and steel wool if you want to do this slowly and entirely by hand.

Thanks. I am concerned only about not reaching with this in every small places, but maybe I'm overthinking it. I can deal with difficult spots individually.

 

[Moonw]

Based on my findings, hydrogen embrittlement is really only a concern if you're really putting the juice to it (which you shouldn't be) and it wears off as the hydrogen outgasses from the metal. If you really wanted to be obsessively careful you could speed up that process by baking it out, but the kind of embrittlement that you see written about is usually in reference to high-strain/repetitive fatigue structural or mechanical components where the forces involved are much greater than those of a hand tool and/or involving processes that cause a much more severe degree of hydrogen deposition. Springs are seemingly the sort of object most affected by hydrogen embrittlement due to their thin cross sections and repetitive experienced strain. Axes, not so much. As Jens noted, any embrittled steel likely to fail would be right along the very very edge, and would be removed the first time you sharpened it.

Thanks a lot! I think I will go with a gentle method, trying to preserve as much of the patina as possible. If it doesn't work, I'll leave it a bit in a vinegar bath.