I'm installing some black gas pipe(1" size) and find two types of couplings
being sold, one of which is called "malleable". I know what the word means,
but wonder under what circumstances this type of coupling is preferred or
should be used.

Thanks in advance for a reply.

I'm not really knowledgeable about malleable pipe couplings, however, I
had a Husqvarna off-road motorcycle that had malleable clutch and break
levers, shift pedal, etc. I never had to replace any of them, and I
bent some of them nearly double. They would bend back, never cracked or
weakened in any way. I rode and raced it for well over 5 years and
crashed it a lot. What a refreshing change from the Japanese bikes that
would break control levers just falling off the kick stand. My point is
malleable would be a good thing if there is any stress, and I've broken
a few non-malleable iron pipe fittings and I haven't done all that much
plumbing.

I think it really does boil down to the same concept, that a malleable
coupling can take more stress. I just find it surprising that they sell both
types, and that some people have a reason to prefer the non-malleable type.

Thanks again for the replies.

Smarty


"Eric in North TX" wrote in message
ups.com...

I'm not really knowledgeable about malleable pipe couplings, however, I
had a Husqvarna off-road motorcycle that had malleable clutch and break
levers, shift pedal, etc. I never had to replace any of them, and I
bent some of them nearly double. They would bend back, never cracked or
weakened in any way. I rode and raced it for well over 5 years and
crashed it a lot. What a refreshing change from the Japanese bikes that
would break control levers just falling off the kick stand. My point is
malleable would be a good thing if there is any stress, and I've broken
a few non-malleable iron pipe fittings and I haven't done all that much
plumbing.

My experience comes from years ago disassembling some various plumbing
parts. Cast fittings could be removed by holding a sledge hammer to one side
and hitting the other side with another sledge. It didn't take much to crack
the fitting open and off the pipe. Malleable fittings were another story, no
matter how many times nor how hard you hit them they would not crack. If you
hit them too hard they would actually bend or deform. The only way was to
unscrew them, and do it before you bent it. Malleable usually means they
were shaped by forging increasing their strength, while cast items were just
poured into a mould with no strength.

"Smarty" wrote in message
...
I'm installing some black gas pipe(1" size) and find two types of
couplings being sold, one of which is called "malleable". I know what the
word means, but wonder under what circumstances this type of coupling is
preferred or should be used.

Thanks in advance for a reply.

EXT wrote:
Malleable usually means they
were shaped by forging increasing their strength, while cast items were just
poured into a mould with no strength.

.....err, no, not exactly. Malleable Cast Iron is what the "malleable"
refers to. Different microstructure and properties than Grey Cast Iron
which is the kind you can break with a hammer.

Both start life as molten stuff poured into moulds.