Bending Pipes for Fuel Tank...

[Scruffmeister]

... what's the secret to bending copper or alu tubes for fuel tanks without them collapsing? I've tried it on my wire bender and by filling the tube with solder wire (not melted!) or silicone wire but still getting far too much collapsing of the walls!

[Koen Smits]

With a wirebender it's almost impossible to bend tubing without collapsing,

Bending without problems with the tool on the following link

**LINK**

Or fill the tube with very fine flower, fill in as much as possible and bend by hand, between tumb and fingers.

[Greybeard]

I use a tube bender like this.

[David Gilder]

Melt a candle into the pipe.

When cool, bend. The wax will prevent the pipe collapsing.

When bent, reheat the pipe and the wax melts out.

This is how they bend the pipes for brass musical instuments!!!

Hope that helps!!

Edited By David Gilder on 06/03/2013 16:32:16

[Prop Nut]

I've always used K&S tube benders on copper, brass and aluminium, with excellent results. They only cost a few Pounds, but last forever. You do need tubing of the correct malleability, of course.

[Scruffmeister]

Thanks all - I've bought some of the K&S ones.

@David - I tried the wax idea. I now have wax all over my heavy vice With small internal diameter tubes I was struggling to get enough (any) wax to enter the tube before it cooled...

[Myron Beaumont]

Why not push your tube into a candle OR dip the tube into molten wax ,block off an end. and then withdraw.?

[Steve Hargreaves - Moderator]

I use the K&S Tube benders too but you really need to anneal the tube first if possible......heat to dull red & leave to cool or quench in water.

Once cool the tube will be quite malleable & bend easily....

[Nick Syminton]

Piece of dowel about the size of a pencil or pen. Lay the dowel flat and roll the tube back and forth, applying pressure at the same time. The bend is effectively fashioned on the piece of dowel. Of course, you cant really get right angled bend with this method, but usually enough bend for fuel tank purposes.

[Martin Harris - Moderator]

You might not want to follow that advice if you're bending aluminium tube...

To anneal that, rub ordinary soap onto it and gently heat until the soap turns black. This is the correct annealing temperature.

[Peter Miller]

Dubro do a good tube bender, Look on the J Perkins website

[Myron Beaumont]

By preferably annealing first as suggested ,you can ,if you have enough disposable length ,fasten down one end and grabbing the other PULL over a radius .That way, you are stretching the outer surface rather than just compressing the inner one which of course buckles the pipe on tight radii. For fuel tanks I've never had a problem as the tube supplied seems to be quite soft anyway .Makes me wonder how on earth we coped years ago when all those fancy expensive gizzmos weren't around .I do actually ----We improvised !

Edited By Myron Beaumont on 06/03/2013 19:09:37

[Scruffmeister]

Does the annealing apply to both brass and alu tubing?

Edited By Scruffmeister on 06/03/2013 20:27:59

[Tom Sharp]

I have many handy tools as above but they disappear just before I need them.

[Malcolm Fisher]

Copper can be heated to dull red and then quenched in water. For aluminium use the soap trick to indicate temperature as described in an earlier post. Some aluminium alloys stay soft when quenched and then "age harden" over a period of time

Brass is again heated to a dull red and allowed to cool slowly., Do not quench or try to bend it while hot as brass breaks easily when hot. a condition known as "hot short" in brass foundries.

Malcolm

Edited By Malcolm Fisher on 06/03/2013 20:24:17

[Steve Hargreaves - Moderator]

Martin is correct Scrufmeister....my advise was for copper or brass tubing.....aluminium will melt long before it gets to red heat.
As Martin says...rub aluminium tube with soap.....heat until the soap goes black &allow to cool.....the aluminium is now annealed....

[Scruffmeister]

The length of this thread tells me that metallurgy is close to the modeller's heart Thanks for all the tips chaps. I'm going to try alu + soap + heat followed by the K&S springs! Now just need the postman to show up...

[Martin Whybrow]

I push a length of the largest diameter solder that will fit into the tube before bending; once the job's done, I heat the tube with a heat gun to melt the solder.

Edited By Martin Whybrow on 07/03/2013 00:11:59

[dbflyer]

Here is a pipe bender for small bore pipes, only about $6 plus postage.

http://www.hobbyking.com/hobbyking/store/__11471__Pipe_Bender_w_Spare_Pipe_3_2mm.html

[Bill Brown 3]

i shove a welding rod in mine, it stands up to the yank needed to remove it.

[tech-ad]

I have used the largest weed wacker plastic line that would fit, as a filler. I have bent steel brake line on a 1/4 inch radius, dirlled several 1/32 inch holes for a smoke system, and easily pulled out the line afterwards. For larger tubing I would use as many lines as necessary.

[Former Member]

[This posting has been removed]

[Bigflyer88]

Just a thought but in industry we use external springs to bend small pipe I reckon there's a ball point pen lying around somewhere with a suitable spring in it. (once annealed).

[Peter Miller]

Posted by Bigflyer88 on 25/07/2020 07:52:36:

Just a thought but in industry we use external springs to bend small pipe I reckon there's a ball point pen lying around somewhere with a suitable spring in it. (once annealed).

From my own experience, I would imagine that a tube would kink and ccome through the side of a ball point spring which is pretty thin and widely spaced.

WE used to use internal springs for tube bending.

Dubro also make a proper tube bender which works pretty well. Two sizes 1/8 (not in stock) and 5/32 in stock.

I have the 1/8th one somehwere

When I make metal fuel tanks I always use 1/8" copper tube. THis will normally bend without kinking but heating it and allowing it to cool will soften it even more.

[Former Member]

[This posting has been removed]