Just bought a parweld 212xxt to learn to Tig after many years using Mig and generally going OK.
BUT I tend to get excessive melting at the start and end of the weld which is untidy. Am I using too high an amperage? Thanks for any advice.
If you can, start welding at the edge and work towards the middle. When you weld to an edge there is nowhere for the heat build up to go. Weld starts are cooler so if you start on the edge it isn't as bad as ending on an edge with a really hot weld pool.
If you are practicing with narrow bar as in your picture then cut two lengths and weld the long sides together rather than the short ones.
You need to forget about upslope and downslope for the moment and get yourself a bigger bit of material to practice on. Trying to do it on that bar is going to be painful, you need to have some flat plate and practice there until you can run some beads nicely, then move on to joints etc later on