In article ,
"Dave Plowman (News)" writes:
In article ,
Steve Firth wrote:
Some say heating the pipe to anneal it first works with modern tube.
I've not tried it.

It makes a difference. Not having a pipe bender for 28mm copper tube,
I fell back to using traditional methods. Anneal the pipe only where
you want it to bend, pack it full of dry sand (molten lead is another
option, but a bit more messy;-). Support the pipe either side of the
bend on something soft (sand bags in my case), and gently step on the
pipe at the point where you want it to bend. Worked perfectly, and it
only bent at the anneal point, very nicely without crumpling.

Me neither, fortunately I'm not trying for a right angled bend. If I
were simply trying to save on fittings I would get a pipe bender, but
IMO the large radius of the curve makes tubes bent in a bender unsightly
if used where they can be seen.

If you have a pipe following the corner of a room, I agree. If you are
referring to an offset for a radiator tail, I prefer the smooth bends
of a pipe bender. Where a bend is out of sight, I'll use a pipe bender
unless it makes the job much harder as it's generally fewer pipe joints,
and the swept curve is lower resistance than an elbow (although not as
much lower as you might guess).

I'd sort of thought the radius of the bend a pipe bender makes is about
the tightest that is safe for a pipe bent cold? And if you need tighter,
you use elbows or bends?

The great beauty of a bender, of course, is that it can be used near
anywhere in the tube. Some say you can bend a right angle in the middle of
the tube using a spring and retrieve it, but the one and only time I tried
I couldn't. ;-)

One slight drawback of a pipe bender is it can only bend with one radius
(at least, I've never seen formers for larger radiuses for same size pipe).
Once or twice, when I've had a pair of pipes to bend in the same plane,
my geometric mind wants the nested bends to have a common centre point
in space, which you can't do as the outer one would need a bending radius
equal to the inner pipe's bending radius plus the pipe spacing. You could
do this with a spring bender. Once I did it by using an elbow for the
inner bend and pipe bender for the outer bend, but that was dictated by
circumstance, not for aesthetic reasons.

--
Andrew Gabriel