Here's a photo from the Ural factory seam welding a gas tank together. When I used to teach welding symbols to the high schoolers, I always used motorcycle and car gas tanks as a perfect application of seam welding. I know that went over the head of a few of them simply because they'd never seen a car or pickup truck gas tank or ever noticed the underside of a motorcycle tank, sad as that is to say. With the Ural, it's pretty obvious where the seam is - right there in plain sight.
It's a pretty neat process, actually. Run the mating flanges of the two parts between the rollers and a series of overlapping spot welds joins the parts with a leak-proof seam. The steam in the photo is from water cooling to prevent the part and the rollers from getting too hot. Next to zero distortion of the parts. Same thing with the required clean-up.
With all the air time "prepping" is receiving, I'm surprised more people aren't considering sidecar rigs. They used to be pretty popular for a utility rig on the cheap. The Ural has a two wheel drive option that will go thru most anything, rain, snow or sleet. Besides that, sidecars are fun. I'm still thinking about a design for the 900. Now that it's getting closer to completion, might want to start designing something in earnest.