Repairing velcro on silnylon.

Small needle, 9 or 11 and polyester thread. Same with hand sewing. Finish with a squeegee and Duco 100% silicone automotive/marine sealant. It will lock the thread in and seal the seam/stitching. Use it on all questionable seams to keep them from coming apart.

BPL also sells Silnet for sealing seams in sil-nylon.

Silnet

Otherwise, I concur with Vick; small needle and polyester thread (I prefer Gutermann’s brand thread in a color to match). A good local sewing store ought to have the thread, or something equivalant.

Jay

Jay,
I can’t recommend Silnet over Duco automotive/marine silicone sealant because Silnet has low tear strength and its higher tack when dry means it will stick to stuff, then tear. Duco is ‘harder’– not as tacky, so it tends to hold up much better as a seam sealer/protector. The problems with Duco are its higher viscosity and faster set time. In other words, it doesn’t ‘flow’ into seams, but has to be pushed or squeegeed. And you have to work shorter seam sections to get the job done before the sealant sets up. Neither is a major problem in light of the superior performance you get from the Duco. This stuff is good enough that you can glue stuff sacks and not stitch them. I’ve also made some stitchless, shaped, no-spill water bags that way. I use a one inch overlap. If I get brave one day maybe i’ll try it with a tarp or something that gets radical stress. By the way, the Duco is MUCH less expensive.