Originally Posted by
Trakhak
Not doubting you or the frame builder you consulted; as I said, I've just never heard of a frame's stiffness being affected by welding temperature in that way. I've just posted a question about it in the Framebuilders forum here.
It was not the actual temperature in degrees, but which tubes where how hot for how long and how things warped from that. The shell was warped so badly that I had to have the threads re-cut. Surly answer on why they would not warranty it was that is normal to have to have the threads re-cut. The mechanic that cut the threads had to take a break half way through because it needed so much muscle. He said he had never seen that much metal filings cut out of a bottom bracket before.
The frame builder I talked to did not see the frame, I was on a tour and had a conversation with her. I was waiting for a laundry machine at a campground when I met her. I mentioned that my Surly frame was defective, she asked what was wrong, I explained, and she asked more and more detailed questions. Then she explained how the heat settings caused it to warp that much. And that it likely was quite weak afterwards. That conversation was in 2016, two years after the frame went into the recycle bin.