[esses]

I have been shopping for pickup truck bed organization racks that are in the thousands of dollars, but can never pull the trigger because they do not seem like they should cost that much. If I can design these to support the weight I need they will find their way in to the truck bed and my overlanding rig.

[sokoloff]

I think you’re far better off with black pipe or rigid metal conduit than EMT (thinner conduit which is not even allowed to support a light or outlet per the electrical code).

Black pipe is still pretty cheap and way stronger than EMT.

[convolvatron]

actual structural steel round and square tube in 20' sections from a steel supplier isn't any more expensive than black pipe and is stronger and considerably easier to work with (no paint, less grainy). you can also make your own fittings since the right tube sizes are nesting. I do 1" square and clamps made out of 1-1/4" with 1/8" wall. that is quite a bit stronger than emt for maybe 20% additional cost.

[sokoloff]

All true; as a DIYer, it's a damn lot easier to buy pipe from Home Depot or Lowes than chase down the local steel supplier and figure out how to either get 20' lengths of tubing home or deal with asking them to cut it for what they know is a grand total of two tubes ever in your lifetime as a customer.

[convolvatron]

the places I go they don't mind if you bring a portaband or a cut off wheel and spend a couple minutes in their yard. actually the place I often go has a chop saw out front. delivery in the city is $20. another place is happy to do cuts for $5, but you have to not mind waiting around for them to get to it.

[conductr]

Probably a little pricier but I’ve had great success with linear rails for projects like that. There’s a ton of sizes and accessories like wheels and plates and various hardware

https://openbuildspartstore.com/linear-rail/

[TmpstsTrrctta]

+1 for rails like these. I’ve used 10 series aluminum extrusions in a roof rack, roof top tent, awning and solar panel setup. I purchased all mine and accessories from here

https://www.tnutz.com/product-category/10-series-extrusions/

[082349872349872]

Incidentally, as a kid I loved Fischertechnik kits; they're like Lego but instead of a brick as the basic element, they have X-linear rails.

[ryukoposting]

One thing to keep in mind with this stuff is that it's really heavy. Regular aluminum square tube is much lighter for a given length/size. If you're making something that moves, it may be worth the effort to grab some plain square extrusion and hand-fabricate some brackets.

[linsomniac]

For a larger project, consider buying from Alibaba. ~5 years ago I built a series of workbenches using 20 series and even with the shipping from China costs, I saved 2-3x over buying from the maker places. IIRC, final total was around $700.

[NegativeLatency]

Took a welding class recently, it wasn’t that hard to get something pretty strong that could be ground and painted to look nice. You could build exactly what you want with a couple hundred for a stick welder and safety gear. Some places that teach welding will also let you rent their gear/shop time.

[potato3732842]

Unistrut is probably the better choice because there's a better/cheaper set of hardware relevant to your use for unistrut than there is for EMT. (Probably because unistrut is designed to hold thing whereas the EMT universe of hardware is more designed for holding EMT to other things)

[quickthrowman]

You cannot use EMT to support actual weight. RMC or 12ga strut can support an actual load.