: Sorry, but as I know, hypalon cloth is not easy to flame. Maybe liquid is
: dangerous, thank you. But I can't find Hypalon cloth widder than 48 inch.
: Would you please give me some shopping information?
: Sorry, my english is not good. What's I use is also pleaster. That's 600D
: oxford with PU covered one side.

: But hw to sewn the Hypalon cloth and Pleaster Cloth together water-proof!?

At first your seam will not be waterproof, even if your fabric is. The needle makes small holes in it as you sew. On calm water this may not be important as the holes are tiny and usually the seam is on the deck, and above the water. If a little water gets into the boat, it can be removed with a towel or a sponge.

Klepper has made folding kayaks for many years with decks that were not completely waterproof, but they did not leak very much, and that was good enough.

Tent makers have the same problem with sealing seams after the fabric of the tent is sewn. They have materials for sealing seams. You might check for such materials. Otherwise, you need a flexible paint or rubber coating that will stick to the fabric and seal the holes from the needle.

Use a few scraps from your material, ans sew some short seams in them. Use these for testing.

If you material is coated with PU, which I suspect is polyurethane, then see about getting some of that. It is used for finishing wood so check with a local carpenter for a sample.

If your fabric is coated with PVC, or PolyVinylChloride, then you might try using the solvent for PVC tubing that is used for plumbing. A small can of such solvent is not very expensive. If you know a plumber who uses plastic pipe you can ask them to try a few drops on a sample of your fabric to see if it works.

Hope this helps.

PGJ