Welding is a process where pieces of similar metal are melted together, and often more of the same metal is added as a 'filler'
When welding a thin or small bit of metal to a chunkier bit, the chunkier bit conducts more heat away from the weld area than the thin bit, and this can lead to the problem of the filler only fusing to the chunky bit in a small area.
This is exactly what I feared might happen when welding the 3mm end plate to the 15mm dia rear axle I made.
On Sunday, I assembled the Windcheetah and rode it round the garden. However, on reaching a small kerb, I kicked on the pedals, in a low gear, to get the front wheels to climb it, and broke the weld on the rear axle.
I really ought to have arraned to have some mechanical means of locating the plate on the axle rod, like the hexagonal other end, so that the torque would be less likely to break the weld.
Tonight I loaded the seatless Windcheetah into the car - A Fiesta!
and popped back into work to do a quick repair.
First I cut some slots with a cutting disc on the angle grinder, so that I could use a washer as a 'key'...
...then welded it up...
...followed by cutting the rest of the washer off and tidying the weld a bit.
I'll try this repair out for a bit, and if I think it will hold this time, I'll use some filler to tidy it before repainting.
I've still got to do some work on the seat-pad, but the next step will be to do a few short rides to find any other
fuck-ups challenges...