I completed the triangle frame and added the caps on the cross-tubes at both ends of the frame.
It was awful. For some reason everything that could go wrong, went wrong. I should have walked away.
But despite the problems I managed to get it closed off. I may try the corner plates tomorrow.
For some strange reason the 3mm steel plate used to cap the cross-tubes was hard to weld???
There is a rust resisting coating on it, perhaps that was interfering, I don't know, it should not have been an issue.
It almost looks like inadequate heat being applied, but 90A was going in and the fact that holes got burnt suggests otherwise.
I will review it in the harsher light of day tomorrow and if necessary I will run the sparkle-stick back over any edges I really don't like.
I did manage to blow a huge hole in the tubing when doing one of the internal fillet joints of the far end of the triangle (the end away from the pivot) and I had to build it back up with weld material. Its not a pretty sight TBH but the damage was repaired by adding filler material to a molten edge and progressively closing the hole. Here is the fillet where it happened. I can take a file to it, but it isn't in the way and its is doing no harm.
So today was a disaster compared to the ease of things and the successes of yesterday. Life's like that.