pipe source for hoophouse frames?

I garden in Missoula and am looking for some used pipe.  I'd like to make hoop house frames, fairly light weight and portable so I can move them to different beds every spring.  I could use poles or lumber but am hoping I can find something that won't rot.

If you have any ideas please let me know!

As you look - keep in mind that a lot of that stuff is not UV resistant.  So it sorta starts to crack and splinter after a couple of months.

Right.  I'm not interested in pvc.  To clarify, I'm hoping to find some metal pipe.  Thanks.

Heavy.

Well, if the time comes and you want to buy something, you might consider the gray plastic stuff that is used as electrical conduit.  It is designed for outdoor use.

Perhaps grow some bamboo.

I have benders for the top post, 1 3/16 pipe, used in chain link fences, the benders come in different sizes for 10-12-16-20 foot widths. 
I also use electrical conduit and a conduit bender for small raised bed sized hoops.

Hey Seth, Yes!  Home grown bamboo would be my first choice but I don't think there's a bamboo hardy enough to get very tall or large diameter here.  I've considered trying black and a couple of others but I've been advised they'll almost always die back to the ground in the winter.  Anyone know different than that?

I've seen an invasive bamboo, or maybe a bamboo cousin? taking over a few friends yards and gardens.  I'm not sure of the variety.  I've never had any of it and they only call it "peckerweed."  It also dies back every winter and doesn't grow to much of a usable size.

I did talk to someone about the gray, exterior pvc pipe recently and was told it would not leach anything at all into the soil, even over time and that it wouldn't begin to get brittle and break down for many years.  I'm still researching that.  The metal conduit seems like an option but it sure doesn't have the connector ease of PVC...

Thanks for your replies!

My friends Dawn and John down in the Bitterroot have bamboo, (self)-perennial, non-invasive I'm pretty sure.  Next time I'm in the neighborhood (soon!) I'll have to check and see what variety...