Best Practices for Not Crushing Thin-Wall Tubing

[Gdeaver]

This post focuses on Al tubing. We have over the years used fiberglass protrusion tube many times with great success. Thru bolts, bearings and shaft present a problem for pultrusions. We fill the area for the bolt with a mixture of chopped carbon fiber and laminating epoxy. Fibers should be chopped to 1/4". We trace out the inner profile of the tube on a piece of 1/4" plywood to make a dam. It is inserted into the tube and held in position with a few drops of super glue.The epoxy mixture is then packed in. We warm the area with the heat gun and it is ready in about an hour latter. Also works for setting sleeve bearings and shaft into the protrusion. Use just enough epoxy to wet out the carbon. I cut the carbon in a home made glove box for safety. Use care when measuring out the un-wetted fibers. Pultrusions are great but require different fabrication methods.