Cheers all. Aye - some of the repair prices from frame builders are well beyond me at present & this is just local & a canny bunch. I was surprised it was so cheap. I was expecting a bit more as the last repair, a split at top of seat tube was also £30 & I guess was a bit simpler. They're a big outfit I just tried because they were nearby but thought it would be a fortune. Maybe they enjoy the distraction from the big projects! http://www.impressivewelding.co.uk
mdvineng":157d1oh0 said:
The blue bits are just oxide layers that were beyond the argon shield protection area. Around 300<340°c temp range. Not an issue.
Aye - they did a good job on it at great price. Plan to be gentle with it. Been a bugger getting a correct shim for it. The one on it is a tad small for my liking & kept slipping at the max torque I was willing to apply but the next shim up won't fit. I've added a coke-can shim all the way...
As titanium is highly reactive when hot and in the presence of oxygen, a good weld in titanium requires what is known as a 'back purge'. A 'back purge' is simply a system that is setup so that some inert shielding gas flows to the back of the weld being made.