I am working on building a teardrop and I am going to weld the frame myself. I've been digging around the internet and the common material for the frame seems to be square tubing, but I also come across people trying to figure out how to stop their frames from rusting out from the inside out so I'd like to avoid that. I live in Virginia Beach, and I will be using this camper extensively on the Outer Banks in NC so salt spray and salt air will be a common occurrence. I'm leaning towards using c-channel for the entire frame so that I can prevent rust but it seems to be less common, so I haven't been able to find as many frame designs.
A few questions.
1. Am I overthinking the rust issue for the square tube frame? Could I weld the tube ends closed to prevent the rust issue? I know that condensation can form inside the tube so could I put some kind of oil inside the tube during the welding process to prevent future rust?
2. Does anyone have a basic design for building a trailer with c-channel? I've found tons of designs for square tube but haven't been able to find much for c-channel.
3. I was thinking I would use 2x3x3/16" c-channel for the frame. I'm pretty sure that that is overkill, but I'd rather have a solid base and cut weight elsewhere on the camper.