We welded (or had it done, rather) our frame for the first time this year, and I was personally pleased, for it helped us cut down on weight (not too many steel bolts), but here's the thing- we built our robot for defense (remember our drivetrain?
), and we made the HUGE mistake of building our gearboxes into the frame as structural members (very bad idea, in my experience). In addition, we didn't use the ever-so-wonderful gussets to reinforce the corners, so after the first day we were doing some massive tweaking jobs just to get the frame square enough to keep our gearboxes from binding up.
As for fixing the welds that broke (all but five or six by the time season was over*), that was simple enough. When we first designed our frame, we had aluminum angle in all the corners and such, and it was welded with those on (we took them off after the weld job), and thankfully someone had the presence of mind to bring them along to the competitions, so when a weld broke, we told one of the newb's to find the right piece and fix it. No big deal, but sort of time consuming.
So I would make these suggestions:
-USE GUSSETS! they would have saved us literally hours of repairs
-make sure there aren't any "vital weakpoints" like our gearboxes
-have the materials and equipment to make quick repairs if you would have to, this saved us several times (all you really need are some flathead bolt, angle, and a drill and bits.)
I think a welded frame, when properly done, has a lot of advantages over a bolted one (like weight and bolts coming loose), so I'd go for it. I think we're going to stick with it, just making some adjustments
Good luck, y'all.
*this was not because of faulty welds, the guy that did them knew what he was doing and the welds were great, but we hadn't engineered our frame to take the kind of beating that it did. (remember our infamous defense?
)