Copper pipe bending

Hi All

A topic discussed in the past but worth a revisit, I need to bend 1/8" copper for lubricator plumbing to a steam inlet tee and 3/16" for feedwater supply for a 5" gauge locomotive.

i have read about filling the pipe with salt, melted solder, sand, etc but what is the most practical? Advice greatly and experience greatly appreciated. Andrew

.

Don't use Solder! ... You will never get it out.

The proper material: 'Cerrobend' or 'Wood's Metal' melts at about 70 deg. C.

MichaelG.

Small pipe benders are pretty cheap anyway.

If the pipe isn't really new then it would benefit from being annealed first.

I have used salt before but that was for an espresso machine with huge tolerances for accuracy and not what id call engineering. It works but i doubt the wall thickness in the bend was consistent or anything

If you have access to back numbers of Model Engineers Workshop , the August 2010 edition, Mick Knights wrote an article about a Mini Pipe Bender which works well for 1/8" and 3/16" copper pipe, I made one and it does all that he claimed.

Yes, 'Cerrobend' or 'Wood's Metal' aka "bend alloy" is pretty neat. You can embed a plastic object in it as it solidifies (how's that for a puzzle!) or just about a finger print but be aware that it contains cadmium, lead and bismuth if people are going to handle it.

Being more of a fool than a plumber, I've never actually used it for bending pipes but it sounds better than the other ideas.

My prefered method of bending small pipes is my twin handled mini pipe bender . It does 3 -4-6 mm o.d. pipes and I find it is much more repeatable than using my mini springs . Got mine from Cromwell Tools , part number KEN 5886080K.

I use "Resin W 8" from John Neale. It is a resin and melts at 70 deg C., and contains no Cadmium. It melts out of the bent tube with boiling water, and the tube walls don't collapse on 180 deg turns. (I make Irish bagpipes, and there are a lot of bends involved!)

Mike

Great advice, all! I had guessed the salt and solder methods were a bit dodgy. Some of the 1/8" bends are very tight so I think the resin idea will probably suit that better than the pipe bender. I still would like a bender for the 3/16" pipe, however. Would there be a copy of the MEW, August 2010 article available in the forum somewhere?

Cheers, Andrew

Hi Mike Hulme, do yo have a link to John Neale so I can get some resin W8 ?

Emgee

Give this company a try They have a product called Polybend which is healthy to use http://www.bendalloy.co.uk/ and are will the sell small quantities.

£15 for 500g inc P&P. Doesn't sound too bad.

Has anyone tried freezing soapy water in the pipe before making the bend ?

This was on 'How do they Do it' when bending tubes for musical instruments and showed no distortion from the round when bent.

Emgee

Andrew,

check your messages re mick knights article

Hi DMB

When bending the ice moves in the pipe so the soap acts as a lubricant to prevent galling the surface of the copper or brass tube.

i think many of you make things far too complicated! ive done many awkward pipe bends on my miniature locos.

i bend the annealed tube between my knuckle joints. as soon as it gets 'tight' i re-anneal.

here's a pic of me doing same to much larger tube for the radiant superheaters for my 5"g current project

cheers,

julian

Edited By julian atkins on 12/03/2015 21:58:15

If you lot read your last MEW properly, you might have come across Field's Metal which is a safer version of Wood's Metal.

www.stop4stuff.com/fields-metal/

I tend to use finger bends like Julian. It can help to use a toolmakers clamp or vice jaws gently fixed over the bend (yes it is awkward) as if the pipe is stopped from spreading sideways it is very unlikely to kink.

Neil

Don't matter what you fill the tube with if you're trying to bend it tighter than the minimum CLR permissible for a given pipe diameter/wall thickness for a given material, especially in toy sizes.

Regards Ian.