Hello. I'm new to these forums, but thought I would throw in my unsolicited 2 cents anyway. My only problem with the whole building process shown in the teaser, is the use of stick welders. Sure it looks gritty and all, but Star Trek is supposed to take place in the future, and using a stick welder to build any vessel of that size is simply idiotic by todays technology and standards. Even hulls of ocean liners are welded by machines using lasers. I'm trying to keep my hopes up that this movie won't destroy Star Trek, but if filmmakers aren't even aware of the world around them, how are fans supposed to trust them with the Star Trek world I live in..lol
Not wanting to be "confrontational"...
... but you're mistaken on a few points there.
First off... there's no such thing as "stick welding." There are a variety of different welding processes, but there is no process called that. (I know what you mean, but being technically accurate is important when discussing technical matters.)
What you're seeing here is called "resistance welding." Basically, you apply a high-power electric charge to the rod of "fill material" and the opposite charge to the base material. When you touch the rod to the material you're welding, a current flows. The resistance at the point of contact is the highest in the circuit, so that point is where the most heat is generated. The heat at that point is sufficient to melt the fill material and the base material, and the melted material merges.
It's called "fill material" because there's almost always a small gap between two plates or structural elements where you're doing this, so you form a fillet of "new" material at that point.
Here's what a typical welded joint, using this type of method, would look like in cross-section. You can see the "fillet" and you can see the two zones of "recrystalization" on either side... between the effectively untreated base metal. Of course, the delineations aren't nearly so clear-cut in reality... it all pretty much "blends" together... but it gives you the idea at least.
For a basic primer on welding, this isn't a bad place to start... though it is JUST a primer...
Your comment that this is "old fashioned" and not used anymore is just wrong. It's the most well-understood, most well-developed, most RELIABLE method we currently have. While there has been some work using beam-welding done, and there's even a small amount of "real life" usage of that sort of technology, it's typically used in very small situations (nanotech work). I've used it to make small electrical connections, for instance.
What they'll be using in ~250 years from now is anybody's guess... but it's not unreasonable to assume that they MIGHT still be using the most straightforward process available.
On the other hand... the trailer might be intended to be purely figurative and illustrative.