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I have a lightweight bike-camping setup that involves a coated nylon tarp over the bike. I'd like to add some guys to improve the shape and stability, but this will require stitching attachment points in the middle of a panel. I'm concerned about the stress on the stitches causing a rip, so how should I construct the attachment points to protect the fabric? I have the tarp and spare guys, but expect to have to buy some material.

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In the case of line forces being attached to a flat surface, the key is distribution. Using a material that is sufficiently strong (webbing), create a panel of substantial dimensions. It's going to be somewhat subjective, or it's going to be trial and error, without substantial engineering analyses.

I'd consider to start with a 150 mm square or a rectangle of webbing about 150 mm long. For "ordinary" fabric strap/webbing, secure the ends (about 50 mm each end) with an unstitched segment in the middle. Your cording can attach to the gap, while the forces are spread over the ends.

If you require more strength or security, consider to place one layer of webbing on the outside (rope side) and another on the inside. Running this concept even farther, use an adhesive. A problem arises with nylon, as very few adhesives will stick to nylon or polypropylene (a common tarp material).

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  • On other tents I've had, while the line attachment itself is webbing, it's normally small, and sewn to a lighter load-spreading piece that looks the same as the tent fabric.
    – Chris H
    Sep 2 at 13:48
  • As for the problem with adhesives on nylon, that is one of the advantages of using webbing on both the top and bottom of the tarp. If the webbing is something other than nylon, something glue-able, then the glue can saturate through the nylon and bond both webbings together like a sandwich. Like the actual binding thread, the threads of hardened glue between the webbings will hold the nylon together and in place even if the glue itself doesn't stick to the nylon. Sep 2 at 14:08
  • @HenryTaylor I'd hope the glue wouldn't soak through, because it would have to destroy the waterproofing to do so. Obviously stitching pierces the waterproofing, but that's what seam sealant is for (it's also adhesive but not very strong)
    – Chris H
    Sep 3 at 8:31
  • @Chris H, If the glue soaks through, it would "replace" the waterproofing and be waterproof by means of displacement and adhesion. Seam sealant is certainly warranted and may soak through as well, accomplishing the desired task.
    – fred_dot_u
    Sep 3 at 13:20

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