Welding Tips and Tricks

Hi from NZ.
I’ve been dabbling in Tig welding for a bit, I borrowed a lift tig machine and did some tack welding on my project (little bi plane rebuild )
I recently bought an AC DC 200E machine from Weldpro same as a Bossweld it’s a relatively cheap Chinese machine but seems to do the job and I’m only doing very light work with short runs.
I’ve been practicing and feel I’m ready to do some real parts now.
I’d like some feed back on my welds please. Can anyone spot some major problems ?
Thanks for taking the time to read this.
Cheers Dom

I’ve cut the tubes and cleaned them up a bit, seems some cross sections are quite good (to me) and others have some areas that contain small voids at the root of the joint. Section DD is one where I did one pass on one side and then 3 passes on the other side, just to try it out a bit.