Sand bending pipes / exhausts

[Roman]

Anyone done this before? 
I realize it's not cost of time effective compared to welding pipes together. 
But it's also bloody cool / oldschool method.
Not planning on doing it myself, just wondering if anyone out there has had a play with the idea.

Basically the concept is that you pack a pipe full of dry (important to be dry...) sand, then heat the area you want to bend with a blowtorch. 
The sand ensures the pipe doesnt fold or crush. 
Here are some cool looking sand bent headers from an old timey Grand Prix car 




popular with bike guys 



 

 

[thegreatestben]

Some good vids on this channel of process

https://youtube.com/@shiroh73

[sheepers]

it is WAY harder than it looks. 

having tried it on some small pipe i wasn't able to get a flowing bend of any description.

however, i was only using a small propane torch and i definitely didn't have enough heat. 

[sheepers]

also i have heard that the guys bending F1 exhausts in the 70s had a torch with a ring of flames coming out of a special nozzle so it heated all sides of the pipe at the same time.

never seen one or a picture of one so could be bollocks but whatever. 

 

[tortron]

Just use a bunch of firebricks to reflect the heat. Typical of building bicycle frames with a weak torch 

[GregT]

57 minutes ago, sheepers said:

also i have heard that the guys bending F1 exhausts in the 70s had a torch with a ring of flames coming out of a special nozzle so it heated all sides of the pipe at the same time.

never seen one or a picture of one so could be bollocks but whatever. 

 

Not bollocks. A mata of mine used to do pipe systems like that. I've seen the setup and watched him do it. LPG/oxy gas mix with as you say a ring of jets. From memory 5 jets on the ring. Yes, loads of firebricks around to keep the heat localised. Several sets of pegs set into a big steel benchtop to put tube into and pull it round. Plenty of space needed too. Plenty of practice too before you get good at it.

You also need the finishing tools. Set of steel balls on chains. Heat pipe and pull the ball through to remove any crimps. More time and gas.  He stopped doing it after a while and got a paying job as he simply wasn't making money. Smallish local market and a limit on what he could charge.

[Muncie]

Did it as part of a vehicle restoration course decades ago on some aluminium pipe and steel, heaps of heat needed and patience.

I have done with copper before making coils for my whisky still worked really well.

[ThePog]

When I built my fatbike it had some difficult bends in the top tubes. I tried the sand bizzo but as I didnt want to apply heat it was shite. I ended up buying a very long spring the same diameter as the pipe ID, this kept the shape really nicely even though it could be difficult to remove afterwards.

[NickJ]

Used to do sand bending quite a bit on 2" tube, we'd use a length of rebar to pack handfuls at a time of damp sand, weld up the ends then bend around whatever was the right diameter, no heat needed. Washing the sand out afterwards was the biggest pain.