E glass equivalent to S glass weight?

Thanks for that data source, there is a lot there to chew on.
I have used ballistic nylon on some SOF sailing canoes and kayaks, I chose that over dacron as i heard it was far tougher and elastic. It does however really sag when damp or wet, despite pre-wetting and stretching on applying. Im still using my first build kayak, it still relaxes after some time afloat, but still tight as a drum in the sunshine. The ballistic nylon i used did not have a high yarn count to some later material I was sent, which i was told does not have such a sag issue. Despite being tough and elastic, one landing onto a concrete slip was enough to shred the fibres to fuzz and resulted in a hole, later sewn up with a patch and built up epoxy, no problem since. It would certainly be worth doing a test panel of that along with the others.
Again, the ply hull can stand on its own, the sheathing is more for abrasion resistance. I coat bare ply with 3 layers of epoxy to build up a good barrier, adding a lightweight but tough fabric to the exterior is not going to increase the epoxy use a significant amount.
I will try and digest that info. I may have further questions later. Thanks.
Edit to add. My old Waterwitch ketch was sheathed from new with cascover. It was maybe 35 years old when i got it, and had some bubbles that i cut out , only to find that it took no effort at all to peel it off. The plywood underneath though was in good shape, but where the sheathing had been damaged along the chine, was some issues. It was a very tight weave cloth, I imagine due to the way it peeled off, that it was applied dry, and resin was applied only from the exterior, except at the edges.....which needed a 60 grit to remove. Certainly it was effective where stuck and undamaged.

 

I would have not noticed that, as it is, i have neck ache from looking at that source that loads sideways.
I have found a supplier of Diolen, not dynel, but made from the same polyester. 300g/ 8oz. As im not looking for stiffness, but rather abrasion resistance, it seems like a good choice, if a little more expensive than E or S glass.
Im looking for a source for some 2165 standard type E glass, as i have no cost comparison to the diolen.

The 2165 (E glass 140g) showed 211 lb sq/in break and the 300g diolen 300 lb sq/in . Seems to show 2 layers of 2165 would be ultimately stronger than the diolen for possibly less weight by some margin. Either way the underlying plywood would fracture before the sheath gave up.

 

I looked at your pictures of the SOF boats under constriction. I posted some pictures later on the same thread. I gather that you wetted the cloth with the spray bottle, stretched it with the fabric pliers and stapled it in lace while damp. Based solely on the three pictures, so I may be wrong.

The canoes in my pictures were done a little differently. The dry Nylon skin was draped over the canoe as shown on the left in the third picture. One stem was stitched as shown in the first picture (the closer stitching close to the stem). I didn't take enough pictures, so the picture is of the second end to be stitched prior to wetting. After stitching the first end, the looser stitches that are several inches away from the stem were used to mark the length of the dry cloth. The cloth was then pulled up from the first stem ans slid down the canoe about the width of one hand, which is a precise as we bothered to go. The picture shows the second stem with the closer spaced stitches. The first stem looked the same except for the lack of the looser stitches. This is also a poor example not only for the lack of pictures, but the cloth had been cut too short to complete the line of loose stitches. The second stem was stitched closer as shown so the skin was shorter than the boat at this point. The skin was removed, dunked in a tub of cold (temperature is not important, just straight out of the tap) tap water and stretched back over the boat frame. At this point the boat was turned over and the edges were stitched loosely with Nylon twine like a corset. This was pulled tight and tied off to stretch the skin and keep it from shrinking as it dried. After the skin dried, it was stapled to the chines and the ends were trimmed and stitched much as shown in your pictures. They stay pretty tight when wet.

The link from my last post on this thread (PU used for SOF boats) is to the only source of ballistic Nylon that I can find. Corey mentions international shipping on his site, so this should be available to anyone.

While drifting the thread, I might as well throw out flax cloth, which is used in the phenolic sheets often used to make sheaves. Just a footnote for fun, I'm on no hurry to sheath a canoe in linen.

 

No, you are quite correct. My first build, the Mobjack with a sewn centreline on deck was hard work as that same ballistic nylon would pull apart while being drawn tight. I used stapels on the sail canoe and this at least left no gaping holes to fill. I got some samples of another nylon that was far superior in weave tightness, though not yet built another SOF. The import for material and "goop" from Corey in the US was prohibitive given the import duty and taxes. The new Polish source is vat and tax, import free.
I think i have enough left over to make up some test panels out of curiosity, it was not particularly cheap and the sag was a little disappointing. I would be more tempted to try dacron/polyester next time, as nothing would see extreme use. Thats a nice canoe!

 

So from a strictly abrasion resistance perspective, with no regard to other mechanical properties, what fabric is currently considered the best?

 

Steel

 

A material, yet not a "fabric".

 

From what i have read so far, highly elastic polyesters like Diolen, Innegra and Dynel that soak up more epoxy than glass fibres.

 

Basaltex in Belgia I've used.. very good experience with them.

ps. Basalt is also easier to laminate, it wets out epoxy resin much better compared to glass.

 

Thanks. I have reached out for product info.

 

I rather liked the description of the joys of applying cascover in this video (Wharram Women):

It should start at 50 sec where they describe applying it.

West has a decent description of abrasion resistant coatings. It seems reasonably accurate, but is limited to their product line. They did not mention that Dynel, Xynole and Innegra are lower strength lower modulus fibers that are not structural, but do add toughness and some abrasion resistance. As for powdered additives, I would recommend silica and silicon carbide powders over aluminum. Fumed silica and silica powder are very different, but both are effective for abrasion resistance and hardness. Fumed silica is an effective thickener in small weight percentages, so it does nothing to extend volume and reduce overall cost. Fumed silica in small quantities does improve the handling and finish of filled epoxy, so I use it in addition to other fillers. If you look at the SDS for the various West fillers, they all contain some fumed silica. I would be surprised if basalt is substantially more abrasion resistant than glass fiber. The wetability should be more dependent on the finish and weave than the fiber. Both glass and basalt would need a silane or similar, so the resin never contacts the fiber surface directly. One of the most important variables is thickness, so regardless of the fiber, more is better.

The two most abrasion resistant paints that I know of are Ceram-kote and Siloxirane Marine line. Ceram-Kote is excellent, Marine Line is substantially better. Marine line was too hard to scribe by hand with a carbide cutter for a corrosion test. The lab had to resort to a carbide rotary cutter to score the paint. It is not widely available, but it could be the hardest, most chemical resistant coating around. It may be too hard and stiff to use as a topcoat over fiberglass coated wood. For an outer layer of glass with a resin binder, POR-15 is worth looking at, but I need more information on that combination before making any recommendation.

 

A friends glass fibre boat lives on a beach going through tide cycles, and often will dig itself into the sand if the surge is high. He reckons he has lost maybe half inch off the bottom of his keel moulding. (internal lead), but that is over more than a decade.
Fumed silica is one i keep on hand, it seems as fast as wearing out glasspaper as milled fibres.
As to the paints, interesting. I did once use Imron clear coat, and that was impressive for a tough finish. Thanks for the interesting links Dave.