Overdue update!

[Niels V]

Hydrogen embrittlement is definitely some thing to be considered, when using electrolysis, as it can cause rapid crack formation and failure of a component.
That being said, it is predominantly the case for high strength steels, low grades are not so susceptible to embrittlement.
I would not use electrolysis for something like the U bolts that holds an axel to the springs, leaf springs or tow hook etc.
The effects of hydrogen embrittlement can be mitigated by heat treating the steel after the electrolysis to drive the hydrogen out.

[Andrew Rowe]

So how do you define a crankshaft as being?,( high grade steel? ) and how much time in the bath will cause this? Does this embrittlement process start straight away , or if something like a crank is submerged for a day, it won't effect it at all? Cheers Andrew.

[Niels V]

Sadly I can not give you definite answer to those answers to that, eg. not sure if its cast or forged.
actually this the wiki article not to bad https://en.wikipedia.org/wiki/Hydrogen_embrittlement and its also worth maybe checking out the references.

[Andrew Rowe]

And he only wanted to clean the parts...........!

[Niels V]

Yes there are always pro and cons to any treatment process.
For something like engine parts I personally would lean towards, water polishing or dry ice blasting, as these would leave a minimum of residue.

I am not sure about how the production process or materials of the Flathead crankshaft, something like case hardened journals could be susceptible hydrogen embrittlement.

Sadly I cannot ask my professor in surface treatment and material science any more.

[Lynn Eades]

The process of re chroming or indeed chrome plating can cause hydrogen embrittlement. Any process that increases hydrogen at the surface of a metal weakens the metal and can lead to premature failure. The process of increasing nitrogen at the surface toughen the metal (nitriding) I think hydrogen embrittlement can happen to a range of "ordinary" steels which would include a cast steel crank.