Originally Posted by tmcrude
Thanks. Looks like 6061 is sold in 1/4" O.D. increments and then each O.D. has various wall thicknesses? Hollaender fittings say their 3/4 size fits 1.05" O.D. tubing so does that mean you use a 3/4" fitting with 1" 6061 and get a tight fit despite that 0.05" discrepancy?
Also, I assume it would be a bad idea to use a steeltek fitting (stainless set screws) with aluminum tube? Wouldn't the set screw just dig into the tube? Maybe that would still work?
How about vice versa? A fitting with aluminum set screws into steel pipe or conduit?
Hollaender fittings use pipe sizing. You should be able to find aluminum pipe... so just get 3/4" Schedule 40 Aluminum pipe.
I'd generally stay away from mixing materials but I'm pretty sure that the Hollaender fittings use 304 stainless steel set screws (https://www.buyrailings.com/product/set-screws/3722
) so it could be assumed that that an aluminum set screw would be fine with that...but that sounds expensive. If you were gonna use a more common steel and aluminum together, I'd at least try to paint the parts that touch so you don't have to worry about galvanic corrosion. Probably not a big deal as long as you keep an eye on it and take it apart and clean it occasionally...but it certainly wouldn't hurt.
Last year I made a frame with 1.25" 6061 tubing and Hollaender fittings and it was light enough to toss around pretty easily and did a great job.
I sold it when I sold the mini-max it went with. I think ideally I would use bends at the corners instead of fittings...but it did the job. Probably lighter to just bend a frame up and weld it...but there is something to be said for modularity and the ability to break it down. I used those fittings and tubing to make a trailer frame for my cat this spring too...and regularly moved the bars around to fit different coolers and dryboxes too.
I imagine 3/4" might be kinda skinny for rafting use...might consider 1". I know the 1.25" stuff didn't feel overly bulky and it works with all the NRS accesories and many from DRE and others.