Protecting Raft from Ill-fitting Frame
So I built this breakdown, double rail frame using Zorba-The-Greek's excellent machined aluminum fittings. I intended to use it both for my new cat and my SB raft, so I made all the cross bars based on the centerline deminsions of the raft tubes. The problem I'm having is that the rails don't fit the smaller raft tubes (19.5") well and the frame chafe is between the rails. The U-bolts rest directly on the tubes, rather than the chafe layer.
Anybody have any experience wrapping frame rails (1 1/4 inch alum pipe) to protect the rubber? What did you use and where did you get it? I've seen polystyrene foam pipe insulation at Home Depot but only for up to 1" pipe. I was thinking if I can't find 1 1/4 then I could use zip-ties to fasten the smaller ones, but will it hold up to multi-day trips, or should I spend more $ and just get Zorba's 6" wide fittings to replace the 9 1/2" I already have?
I'd really rather not spend more, nor have a second frame to store. So protecting the raft tubes is first choice by a wide margine.