I learned a trick from a welder friend. I was having trouble with welding another tube to a seatpost. It seemed like alot of the time i either burned a hole in the seatpost or just got it really hot and it deformed. If you burn a hole ,the metal will go inside and then later you will find you can't get the seat tube in. The fix is ,if you slide a piece of copper tubing inside the seat post it wont let the weld burn through. It dissapates the heat and weld won't stick to copper. I use copper plumbing pipe with a 1'' od and it fits perfect.
