Hi Fred,
If you don't come right, make you own, here in South Africa, you don't find them they are luckily easy to make. Get the pipe you diameter you require, wrap around a 4" wide piece of plastic at a angle beginning to end and tap it in place with masking tap. Backing to heat shrink covering works well. Make sure the tube will be more then you require. Then wrap fiberglass cloth / Tape the same way as the plastic, brush on epoxy resin or K&b Resin over this then leave it to get hard. if you want to get ride of extra resin, heat the inside of the pipe with a heat gun the resin will thin, and can be dabbed off with kitchen toweling. wait for it to harden, score a line round the masking tape area to expose the plastic, you should be able to remove the plastic. giving a you a 100% perfect fit tube with no slop.
regards
Sean