compression strength of 1 inch aluminum tubing

You will need to evaluate the failure mode. Long shapes fail by "Euler buckling". Short shapes fail in the expected crushing mode.

the load on the tube has a lot to do with their end conditions, whether it is simply connected or moment connected, and how it is loaded. for just compression, stress equals force over area. for buckling, Pcr=pi^2EI/(KL)^2. if K=1, both ends are pinned, if both ends are rigidly clamped, K=.5. if one end is clamped and the other end is pinned, K=.7. if the columned is cantilever and loaded at free end, K=2.

reference: statics and mechanics of materials by nash, schaum's outline.

from fred.