Folding Kayaks Forum

Take a look at Malcolm T's posting in another thread on this part of the board. Definitely moving toward potential answers

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Chris T.
~'91 Klepper A2 w/ BSD schooner rig.
'64 Klepper Passat/Tradewind and T12 restoration projects.
Non-folding: Early '90s Old Town Canoe.
Previously owned '04 Pakboat Puffin II and '05 Swift (prototype), as well as an '84 Hobie 16.

I was out today to see how well I could clean the deck. I experimented with TSP on one part and ordinary dish soap on another. Meanwhile, I inspected the hull (it's black hypalon from the 90s). The coating on the inside is coming off in patches, especially on the bottom. Some, though much less, is coming off on the exterior. The outside seems in better condition than the inside, thought there's a fair big of cracking. The underlying weave is discolored but seems fine. I wonder if it's polyester and not cotton? Of course my thoughts are running on this: Maybe I should try scraping whatever coating is coming off and then applying some of Malcom's coating to the places where the weave is exposed? The worst deterioration in is in the bumpers on either end. They're just crumbling. Some of the extra strips added to the hull---this is an expedition boat--are cracking or coming off. The canvas deck seems pretty good to me, but I'll see for sure once it dries. A woman at Klepper told me that I should use a "neutral" cleaning solution, although I'm not sure what that is.

Hi.

Avino E is a multifilament polyester thread. Polyester won't swell. Amann Serafil and Ariadna Tytan are similar products. Can't find 11/4 on the Kupfer homepage http://www.naehseiden-kupfer.de/produkte/polyestergarne/avino-e/. The closest equivalents listed are 11/3 and 10/3. 20/3 (138 in US-designation) can still be machinesewn with size 140 (22) needles. After that it's professional territory.

Thread that can swell typically needs natural fibres like hemp or cotton. To combine the tensile strength of polyester with the ability to swell of cotton you would chose corespun thread with a polyester core and cotton surroundings like Kupfer Intra or Amann Rasant.

For a tensile strength comparable to multifilament thread a corespun thread must be thicker, which means bigger needle holes to start with. The cotton then can function as a wick, actually sucking water through the hole due to capillary effects, and ultimately the cotton will decay due to UV-radiation, moisture and friction, leaving the big needle holes. I once talked to an Amann technician about this, because I wondered why they didn't mention the swell effects in their advertising. She said, they had read about supposed swell effects in the internet but have not been able to confirm the effects in the lab. Amann recommends WR (water repellent) thread to avoid the wick effect and additional seam sealing if the holes are expected to be watertight.

HTH
Greets
Ralf C.