Just a bit cold mate that's all, two options turn the feed of the wire down or turn the heat up. For that sill section I'd say turn the wire feed down and you'll hear it sounds much better and the weld wont be as cold as there's more heat into less wire

I just recently bought myself a welder too. a cheap flux core one from lidl.  I plan remake my campervans bed from box section rather than wood. Now, im clearly not in a position to give you much advice as im only learning myself but I would say you probably need to turn up the power on the welder and maybe the feed speed.

Exactly  where mines going  ,think I could have a blast at that cheers jeol  ,practice  makes perfect 👌

Again mate get some more heat into it. I have no doubt the repair you've done will hold. Have a google of "cold mig welds" thats what you've got there but well done on your first repair!

Well done mate, 12 out of 10 for that. Along with the advise that you’ve had make sure you weld to clean solid metal. Great effort and loved watching you do that 👍🏻

What paint are you using? Fighting rust on a T4 is ongoing. I've started buzzing back to clean metal, painting with "Mipa Rostversiegelung" (corrosion sealer), and then painting with an epoxy primer. Then using something like Epoxy Mastic 121 as the paint, then a top coat.

Exactly the same boat as you Joel, am about to start doing some welding on my T4. My sliding door bottom area also rotted out.  Did you disconnect the vans battery etc? I'm a bit aprehensive as im going to be welding in the driver and passenger step area, so its close to front end electrics. Worth taking the plastic steps out and checking your own van there, a lot of T4s seem to go in that spot.