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David - from that experience can you intuit anything from Bob's worries re spokes? i.e. is the issue the period of loss of Hydrogen... or the structural change as a result of this?
Clearly, its something that shouldn't be done if there are are concerns, although presumably this process is only operating on the mere surface of objects? Or not?
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I am not a metallurgist! I had people working with/for me who really understood this stuff! All I knew was that hydrogen embrittlement was BAD NEWS! I imagine it caused structural change, very important when hardness (self tappers, thread formers HT bolts etc) was important.
What was of note was that eg screw heads popped off several hours after installation when the fastener had been put under load. I don't recall them breaking up in the box! So on spokes I would think that breakage would be pretty soon after installation/use under load.
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There is much info on embrittlement available but little is succinct. Mild steel is little affected. Many processes involve acid; pickling, reconditioners hot tanks etc but not all always followed by cancelling processes (like baking).
To play safe stressed high tensile parts which wont fit in the oven should best not be subject to either process. Failed spokes are a real pain. The original spokes are not mild steel and in normal state withstand remarkable abuse.
Do the acid concoctions sold for rust carry any warnings?
(The effect of embittlement and actual electropalting on fatigue is almost another subject, and even less encouraging)
if cleaning spokes by shot blasting care is necesary not o stretch the spokes.
A popular school science display is to hang a weight from a spring. Acid is dropped onto the spring and sooner or later it snaps.
