How did you make the post holes in the concrete?
So the posts are set with sackcrete like a fence post dug out a hole and then also drove them in some with a post driver.
I have had to do some previously on top of block steps. On those I just welded plates to the bottom of the posts and used anchor bolts and then covered them with a post base cap from Amazon. I am going to have to build the ones up in the deck and mount them to the cedar 12/12 posts .
These are built in place very custom work. Most times I just use square tube and cut and weld miters this is the first one I’ve done pipe. I prefer the square it is much faster.
I bought a little Hobart handler 140 that I have been using it’s not really hot enough to weld great but it’s the best I can do on 110 v on extension cords. I have used the stick welder with some but I’m not as good as @JO_Olsson I can’t get a perfect weld on this thing tubing it’s easier just to grind extra after the mig