Performance in the wind: bonded seams vs traditional felled seams?

[Matt Dirksen]

Good luck with the experimenting and please keep us informed!

I must say that the largest number of failures I have personally experienced was due to “bonded” seam failures on several rainjackets after years of mixed use. While I’m sure the initial stress testing of bonded tent seams appears to be very promising, I’d really like to know how the bonded seams might perform after 3-6 months of 100% UV exposure and repeated tensioning and crumpling.

[Sam Farrington]

Geoff,
If you are going for 30 deniers, the sil/poly Extrem Textil from Germany is by far the best for those willing (or able) to carry a heavier tent. Monte also advised me in favor of the Extrem Textil; but I want a lighter weight tent, and as noted will be using sil/poly cut from a Yama tarp even though it is on the dark side. (There will be a very light sil’poly partial inner.) The Extrem Textil also comes in a nice light sand color, and I would buy it in a minute were it lighter. And it is closer to 2 denier than 3. Note that polyester is much more resistant to heat and distortion than sil/nylon. (Sil/nylon looks great when new and dry though) Note: The Extrem Textil was sent to me in the USA only on condition that I agree to their more expensive shipping.
Happy Trails and Beaches.

[Justin W]

I bought a bunch of silpoly fabric from Extrem Textil awhile back and plan to make a large tarp at some point. I’ll probably use the bonding method described in the OP, but I do plan to sew as well. I’m interested in the bonding, because sometimes when I sew thin, lightweight silicone coated fabrics, it mis-aligns. Bonding first will prevent that, and probably add a little extra strength/durability in combo with the stitching. In fact, I just might sew a single double stitch line (my sewing machine does this automatically) over the overlapped/adhesive bonded part. Sure, it’s more work, but I want this tarp to be particularly durable/long lasting.

[Jerry Adams]

Mis-alignment between the two layers is tricky.

I put a few hand stitches along the seam.  Then, I’ll hold the next hand stitch and pull slightly as it feeds into the machine, keeping the two layers aligned.

Easier than bonding.

Practice with a couple long scrap pieces.

It makes me laugh when I get to the end of the seam and notice they’re way misaligned – “you idiot!”

[Justin W]

Jerry, your method definitely sounds faster and easier. In the past, I’ve used the no sew, heat bond polyamide strips to very temporarily sort of stick the layers together. But it is somewhat laborious and time consuming, and sometimes it comes apart if moved around too much since the polyamide strips don’t really/truly adhere to the silicone coating.

But I like the idea of adding a little extra strength and/or durability with the silicone bonding + sewing. It’s like having a backup in case one should fail. I’ve actually have already tried this method, but did it with non thinned silicone, which was kind of messy and a bit lumpy. I didn’t do any specific tests with it (with the tarp I made my spouse), because I also sewed, but it seemed pretty solid before the sewing.

I’m looking forward to trying the Permatex stuff, as it will be lighter, lead to better aesthetics, and sounds like it will bond faster.

[Sam Farrington]

Geoff,
Thank you much for starting this thread. The many comments suggest a variety of outcomes, but have been extremely helpful.  As a result, am still wedded to polyester (vs nylon), and am still wedded to sewing (vs bonding).  However, without going into the long history of the issues raised on BPL with nylons, there have been too many  experiences with tent failure due to moisture and deterioration.  Tents can look good in balmy weather, but only for so long.

So am ready to try polyesters, particularly those that have held up much longer, and have shown the elasticity essential for high performance in severe wind, heat and rain storms.  Of course, polyesters can vary greatly, but there are now enough examples of excellent performance with some.

Have also read about differing performance with silicone seam sealers;  but if those are limited to the threads, and avoid damage to the elasticity of the seams, they are probably the best option;  and so will have the greatest likelihood of maintaining the elasticity which is critical to a shelter, and not found in expensive laminates and bonding tapes.

Having said all that, it leaves just the design, construction and skills, and those should be a snap.  As Roger once said to  me, “Build the Tent!”  Later he kindly acknowledged that it was just a hobby.  But it is a hobby on which survival may depend; and if well done, can be greatly rewarding in the great outdoors.   Happy Trails.

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