80/20 frame Material Questions

[Ben Piecuch]

Please, general (unqualified) statements about the stiffness, or lack there of, of 8020 material should not be made in this thread. If you actually sit down and do the math, you will find that the 8020, and similar, extrusion profiles offer both lateral and torsional stiffness that is within 5% of 1/8" thick 1x1 box tubing.

Most teams blow it when using 8020 by NOT using the proper connections. The "double anchor" connection is ONLY connection that should be used with these types of extrusions. It offers both the strongest connection, and the lightest connection. It is also the cheapest and easiest of the connections to deal with. Try finding another combination of qualities like that! The joining plates are just the wrong way to go for our applications, as they do not offer the strength, or the weight advantages of the double anchor.

I will also state that 8020 should only be used where it is required. If you plan on building a 5'x38"x28" box, you will run into weight problems. You will find the same problem with 1" box tubing. Only use the extrusions where required, and mate that to a more weight friendly 1" angle for an upper structure.

All this negative talk about 8020 is just reminding me that I should write up that White paper about the proper uses of extruded profiles.

BEN