Bending Exhaust tube with Sand

[Graeme Stebbing]

One of the most usefull things i have found on the net.Been trying to find this out for years.Articles like this stop the knowledge being lost forever.
Toyota V8 and Associated Technologies Forum :: View topic - How to get a perfect extractor primary pipe ??

Thanks ed_jza80 for posting

Lambo

 

[Randy V]

Wow - now that would take a lot of patience! I've heard of it before but not seen it!

 

[RichardH]

another option is to use low melting resin.

 

[Russ Noble]

another option is to use low melting resin.

Richard, any other details?

Cheers

 

[Doug S.]

Wow - now that would take a lot of patience! I've heard of it before but not seen it!

I gave it a try back in the early 70's--had heard of it, but never seen it done or seen any instructions. I was working on a farm and we had a huge propane torch used to heat up the branding irons, so I filled the pipe with sand and then used the torch to get the pipe red hot. The sand inside the pipe acts as a pretty good heat sink, so it takes a long time to get the pipes hot.

I ended up with a lot of kinked pipe. I couldn't figure out how to keep the sand packed tight inside the pipe where I wanted the bend.

Who would have thought you'd need to add more sand??????? All I wanted was a set of "zoomies" for the sand buggy I was building.

Interesting article on the old guy who does this so well......

Doug

 

[Phil]

Gents
I tried this method...wasn't too happy with the results, and as Doug stated the results are a lot of kinked pipes. I have a bender that will do as small as a centerline radius 2x tube diameter, but the catch is the wall thickness. Header tube such as .058 or .065 wall still kinks on the inside, and stainless is really tough. As you go up in wall thickness, .083 or .120 the bends get much better, but not a suitable material for a set of exhaust pipes. The only way I have seen to get those nice tight bends is a mandrel machine (big bucks), and not only is the machine expensive, for a given size tube you will need a mandrel for each wall thickness. All this tooling costs a bunch. I still think the way to go is to buy the mandrel bends and TIG them together, which also gives the option of over bends (past 180*) and closely associated changes of direction, and rotation which usually are not possible due to clamping considerations.
Cheers
Phil