[Tom Line]

Benefits to Welding:
1. It gives some added flexibility to the design process

Benefits to Rivets:
1. Most teams send things out to be welded. This takes time. Even if you think it doesn't - it does.
2. You can take a rivet out. Removing a weld is much harder.
3. You can replace rivets. You can add rivets. At a competition.
4. Rivets are rivets. Not all welds are welds. Welds can look perfect from the outside but if the welder didn't get penetration it will fail at the worst possible time.
5. Rivets are easy.
6. Rivets are cheap.
7. Rivets don't have a safety downside.
8. It's rare you run out of rivet map gas, rivet rod, or jam up your rivet wire auto-spooler.
9. If a rivet joint gets wiggly - add more rivets. If a weld joint gets wiggly, you've got problems.

To be absolutely fair - we welded our chassis this year. We have every year since 2008. We also welded our arms. The connection between our chassis and our arm snapped on our practice bot due to lack of weld penetration. The weld on our arm snapped on our comp bot 3 times because it simply wasn't strong enough. The solution at the competition was flat plates over the weld - riveted on.

In summation, unless you have someone who already knows how to tig weld and you're keen on teaching your students, or you have an over-abundance of time, I'd stick with riveting and focus on other portions of your robot process.

As an afterthought.... look at some of the critical joints on 254's robot. They are both welded, and riveted.