Hello. Here is my problem: I want to mount 2 solar panels on a horizontal 10 foot bar. (panels are 5' and 20-40/lbs each - so 80lbs) is there a formula i can use on each material option to figure out what material to use for the 10 foot bar (what wont break under the weight of the panels or bend or crack from the changes in temp and under load, and which is the cheapest option I'm thinking a piece of 2" PVC filled with cement would do the job but i wonder if it would crack. I don't think 1 1/2 like chain link fence post pipes would be strong enough. I'd like to be able to figure it out with nice cheap math before going out and buying lots of things to experiment with. google was little help with mostly similar questions with answer that say it depends on the material but that's what I'm trying to figure out Thank you in advance for any assistance.