I have been building some custom side steps with rectangular tubing and making modifications to the factory sport/roll bar. The tubing ends will all be capped and welded closed. Will a closed, sealed tube cause rust from the inside out due to moisture/condensation, or should I drill a weep hole to let moisture/condensation out?
I can see it both ways. I'm leaning towards leaving a weep hole at a low point.
Maybe this should be in the fab. section but there is always good input here.
There's only going to be so much moisture inside your capped tube. If you get it good and warm just before welding there will be almost none. It would take many, many years for that little bit of moisture to do any noticable damage to the relatively thick wall of the tube.
With a weep hole there will ALWAYS be moisture in the tube.
This is something I never even would consider living where I live.
Thanks for the input. I like the drill and tap a hole idea. Warm the steel before capping t0 minimize moisture is also a good thought.
While modifying my sport/roll bar I noticed abut a 3/16" hole in the main hoop where the angled back bars connected along with a hole on the bottom of each rear mounting foot. I guess I thought there was some kind of magic reason for the holes. Moisture was the only thing I could think of or maybe it was for wiring of some sort.
I would just weld it closed and be done with it. Unless water gets in thru a "pinhole" somewhere, the tube would take a lifetime to rust from the inside out. If really worried about it, shoot some "Cold Galvanizing Compound" or "Weld-Thru Primer" into the tube before closing it off. Really not necessary though IMO. A threaded plug is just someplace for water to seep in.
As a comparison.. my shop air compressor was made in 1971.. it sits around with moisture in the tank.. and still holds 175psi. No rust thru yet.
'80 CJ5 w/AMC360, T176, D44 w/Detroit 4.56, RE 4" YJ lift and 35s..