[TheForge] fact or urban myth

[Bruce Freeman]

Re:  hydrogen in acetylene equipment being dangerous.

I don't know either way whether this be true.  

However, acetylene is highly reactive and highly
unsaturated, meaning that in principal it could react
with hydrogen directly.  Such reactions typically do
not occur at room temperature, but possibly could do
so in the presence of a catalyst.  Metals and metal
salts can catalyze such reactions.  Furthermore,
hydrogen heats up when it drops in pressure, so
there's a possible source of heat.

Hence, I conclude that this danger conceivably could
be real.  I would think that it would take a
CONSIDERABLE quantity of acetylene for this to be a
danger.

Then again, I could be completely off-base, and the
danger (if any) could arise from something else
entirely.

For example, as someone else pointed out, metal
acetylides are very explosive, and are a chief reason
on the choice of specific materials for acetylene
torches, etc.  Likewise, it's well known that hydrogen
will embrittle copper tubing, which therefore is never
used with hydrogen.  Maybe the deal here is that
what's safe for acetylene is unsafe for hydrogen.

Bruce
OR/NJ

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