The previous owner hacked off the back 6" of the frame to make a "brat" look. Hmmm. I needed it reinstating to carry the rear mudguard and rack mounting points.
I'd got hold of an old frame and chopped off the missing parts. I found some steel tube and cut a couple of 3" long pieces to act as sleeves inside the frame to reinforce the joints.
You may recall that I'd bought an old welder to try and use, but I just couldn't get it to weld consistently. In the end I bit the bullet and bought a new welder - talk about chalk and cheese! Within 15 minutes I was producing decently strong (but maybe not very pretty!) welds.
I mocked up the replacement frame horns, temporarily fitting the mudguard to get everything in the right place and then I clamped it all up, before putting a couple of tack welds in to hold it all together.
Once it was tacked up, I dismantled the mudguard and clamps and welded the joints all the way round, doing lots of small tacks so I didn't overheat it and risk distortion. A few minutes with a sanding disc in the angle grinder got the welds ground down pretty flush.
I was so happy with how this turned out - I'd been dreading doing it, but was determined I wanted to have a go myself. When I measured it all up afterwards and compared it to the factory frame dimensions, everything was spot on within the +/-1mm tolerance they gave!