A $3.00 elbow will work wonders where a tight bend is needed, too.

Jim

On Apr 7, 2005, at 8:27 AM, Joe Knight wrote:

> Short answer is yes, he's correct, Jerry.  But the stuff sold in coils
> is already annealed to allow for a certain amount of forming.
> Shouldn't be an issue unless you need to make a pretty sharp bend or
> two.  Otherwise, keep the radius of your bends as large as possible
> and put in a bit of effort to get it right the first time to minimize
> reworking.  Err to the side of not bending your angles far enough the
> first time to avoid working the bends back and forth.    Years ago, I
> watched a friend, mechanical engineer, put a fairly tight bend in a
> piece of tubing.  He had access to liquid nitrogen, so he filled the
> pipe with water & plunged it into a bucket of the stuff to freeze the
> water and bent the tubing around a pipe of appropriate diameter.  I
> suppose you could do the same if you can get the filled piece into
> your home freezer.  As far as further annealing goes if you find it
> necessary, heating to a red glow is getting very close to the melting
> point for copper and might be difficult to do successfully absent a
> tightly controlled environment.  But it's probably not necessary to go
> that far.  I recently annealed a copper disk enough to allow some
> clean forming by heating just to the point it turned a dull blue and
> letting it air cool.  I'm not at all sure that annealing relieves work
> induced stresses though, so if you're needing to do some real
> aggressive bending, you might want to read up on that a bit.
>
> HTH,
>
> Joe
>
> On Apr 6, 2005 10:28 PM, Gerald Masar <azsun99@earthlink.net> wrote:
>> I am finally finishing a too long project to add a second propane
>> tank to my '90
>> Westy, and have a question for the metallurgists (or anyone who
>> knows) on the list.
>> Yesterday I bought some 3/8" O.D. copper tubing to connect the two
>> tanks, and while
>> the clerk was coiling it up very carefully, he said you don't want to
>> work it too much
>> because it causes it to harden. He called it "work hardening". True
>> or false??
>