This weekend I did a little experiment. I cut off two 1' sections of 8" diameter Quikrete tube to test with a drain sock lamination and a control. I've read about needing to sand off the outer paper since it prevents good epoxy adhesion. However, the downside is that the exposed cardboard soaks up crazy amounts of epoxy.
So I tried this. The Quikrete tubes were sprayed with 2 coats of adhesion promoter-primer. It's a clear primer designed to make the surface readily available for binding. Once the volatile organics dry off, there is almost no added weight. This stuff will allow you to paint PVC with no problems. So I gave it a test with the epoxy.
Last night, I mixed up some US Composites epoxy with the 3:1 medium hardener and put on two layers of drain sleeve. I didn't bother putting on mylar to make it pretty since this is just a test. This morning, I checked the results. The laminate looked good; not too wet and not too dry. The tube hardly soaked up any extra epoxy. The 1' length only gained about 50g of expoy weight (when I subtracted the drain sleeve weight). So I assume most of the epoxy is in the cover with minimal soaking into the tube.
I tried peeling off the epoxied drain sleeve with pliers, and I couldn't do it without taking along half the tube with it.
I put a 2x2x1/2" piece of plywood on top and jumped on it. No crushing or buckling. The dry tube also held up to that, so all I can really say there is that the epoxy or primer didn't soak into the paper tube and somehow weaken it.
Laterally, the tube does seem much stronger. Tonight, I'll test lateral crush. I'll see how much weight it takes before it crushes.
Has anyone else tried this? It seems to hold the laminate well while giving some extra strength without too much added weight. Now I wonder how well a real fiberglass wrap would do. Thoughts?