by P3T3rPan » Sat May 31, 2014 10:37 am
For anyone wanting to avoid this situation in the future, the correct medium to use for supporting copper tube for bending when an appropriate spring is not available, is fine, DRY, river sand, tightly packed and sealed by silver brazing (not solder).
Pays to heat the copper to clean it before filling with sand
DRY because the when the pipe is packed and sealed you can mark out your radius and anneal and re anneal as much as you like.
Any moisture and BOOM
River sand cos there is no salt to absorb moisture
The area being annealed can be contained with the use of damp folded newspaper strips allowing you to control the radius
For very tight radii and offsets it is best to use oxy/fuel gas to help contain the area of anneal
When complete cut off the brazed ends and tap gently collecting sand for reuse