I want to make some coolant pipes for my 3 wheeler project out of aluminium. The coolant hoses are 5/8" diameter so I'll make the pipes out of 16mm aluminium. Without buying special tools for a 1 off job, how do I put a couple of bends in a long length of pipe without kinking it?

B&Q 15mm bending spring £3:38


Bendy Linky

not tried it myself, but aparently packing the tube really tightly with sand allows you to bend it without kinking it.

low melting temp alloy, I have some but how long is the pipe

I know where I can borrow some nice dry play sand. Is it best to warm the tube with a plumber's torch first?

Liam,

I picked up the first lot of steel for the chassis this week so there's some way to go before I need the cooling pipes. The final dimensions to be worked out once the chassis has got some weld in it but probably in the region of 2.4m each. Not something that would post easily.

just asked a mate about the sand thingy and his instructions are as follows:-

stand the tube vertically (after plugging the bottom open and)
fill with water
using a funel, fill the tube with sand until the sand replaces all the water (tapping as you go to avoid air bubbles
leave for a few mins and tap again quite vigerousely (top up sand if needed)
seal the open end with duck tape
bend the pipe at the desired place using your hands and knee/edge of workbench

simples

quote:

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Originally posted by skinned knuckles
just asked a mate about the sand thingy and his instructions are as follows:-

stand the tube vertically (after plugging the bottom open and)
fill with water
using a funel, fill the tube with sand until the sand replaces all the water (tapping as you go to avoid air bubbles
leave for a few mins and tap again quite vigerousely (top up sand if needed)
seal the open end with duck tape
bend the pipe at the desired place using your hands and knee/edge of workbench

simples

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thought i read somewhere to use kiln dried sand, and don't wet it?

if you going to use sand and heat make sure its bone dry, also use a bar of soap to coat the pipe, as you heat the pipe it will turn black showing the right tempture to start bending.

you could also get a large bit of wood, drill a hole the size of the tube, then open up on side on the direction you want to bed.

Put tube in and bend, move a fraction and bend. The wood supports the tube so it can't deform - although you can't do tight bends.

(not tried myself - got from here from people who have).

make sure you practise bending first.

remember sod's law will mean the practise bends end up perfect but the real thing will kink

Using information gathered from this place, I would use a mixed technique, first, anneal the tube using the soot/soap/sharpie mark, then fill up with sand as stated a couple of posts above and bend using the hole in wood.
HTH
AA

[Edited on 6/13/2010 by Angel Acevedo]