After a few delays for various reasons I have finally started work on the body tubes.
As mentioned previously I wanted to strengthen the cardboard tubes with fiberglass sleeves:
I wrapped 2 couplers in Teflon tape and inserted them in either end of the body tubes. The couplers served 2 purposes:
1. They extend the length of the tube so that the fiberglass lays nice and flat at the ends.
2. They strengthen the tube so that you can tighten the ends of the sleeve without crushing the tube.
This is the first tube on a cheap Bunnings rotisserie ready for epoxy:
The sleeve is secured tightly at either end with electrical tape and zip ties.
I applied a generous amount of epoxy with a foam roller and used my hands (gloved) to squeeze it through the sleeve. Then I wrapped it in peel ply and left if overnight.
Unfortunately the folds in the sleeve wouldn't lay flat on the tube so epoxy pooled under the folds. The folds are there because the manufacturers store the sleeve rolled up. The fold is the dark line that you can see at 1 o'clock under the peel ply. It's clearly visible and feels slightly raised.
After speaking to the sleeve manufacturers I made some changes for my second attempt:
1. I turned the sleeve inside out
2. I secured it a lot tighter at either end
3. I left the whole thing on the tube for a week and placed it out in the sun to try to heat and soften the sleeve.
This seemed to work much better as the fold is hardly noticeable on the second tube.
But jury is still out on whether the finish of the coloured fiberglass is good enough.
I had a lot of issues getting the resin to flow evenly into all the gaps as you can see in this close up.
Perhaps I need to thin the resin or switch to a thinner finishing resin.
The fiberglass is fibers are saturated, but there are gaps between the fibers.
But the good news is the tube seems really strong. So worst case scenario is I fill it and paint it.
For the larger diameter body tube I will use a section of 150mm PVC pipe as a mandrel. The sleeve only just stretches over this, so will need reinforcing with some regular fiberglass cloth. The finished diameter will be about 160mm.
And finally here is a rather bad mock up of what it might look like.