NGWClub®, Inc.

Cool.
He was right with the outer pipe. Once you do that then you can make a round
buck and carry the bend where you want.
I didn't see his fire. A shop vac or leaf blower (my personal choice) will
bellow some serious heat. Its gotta GLOW.

Neat How to,
thanks

I have a mandrel bender but when I need to do a special radius bend with sand I always fill the sand with water. If you add the water through a tiny hole in the welded puck last it only needs a tiny tack weld to fill the hole and you won't have blow out problems. When the tube is heated the water expands of course and it helps to keep the tube from collapsing on the inside of the bend.

Another note is that you need to allow for more spring back when bending chrome-moly or Stainless than mild steel. Aluminum has very little spring back.

I was taught to keep she sand dry. That the sand would act as a mandrel and keep the tubing from collapsing.
If the material isnt pressure rated how do you keep it from rupturing when the water turns to steam and the pressure increases inside the tube.
Seems like a bomb waiting to go off

I would avoid any water in this process. When water flashes over to steam, a cubic inch of water will occupy a cubic foot as steam. That's 1,728 times expansion. Not safe! The Navy uses steam to launch aircraft off of carriers. It's not worth getting hurt or killed.
Terry