When you buy a tent or tarp made with silnylon, it’s best to seal the seams using Gear Aid Silnet Silicone Seam Sealer in order to make them waterproof in the rain. While many manufacturers offer this as an add-on service, but you can also do it yourself. Tents that are waterproofed with polyurethane or polyethylene (abbreviated as SilPU, PU, or SilPE) are usually factory seam-taped and are often sold that way out of the box.
Here is a simple guide to seam seal a silnylon tent.
- A brush that you don’t mind throwing away afterwards
- A tin can or something to mix up in
- A bit of card, or a very steady hand
- Damp cloth
- Gear Aid Silnet Silicone Seam Sealer, which is sticky messy stuff
- Paint thinner
Start with mixing at 3 to 1 paint thinner in a tin with Silnet until it is a workable viscous paste that can be easily applied with the brush to the seams. The whole point is to get it to soak into the stitching where the water could penetrate. If you were to apply the Silnet without thinning, it cures too thick and can flake off leaving a messy look. One 1.5 oz tube of Silnet will usually be enough for a 1-person tent if its been diluted with paint thinner as described above.
Note: You want to seal the seams on the outside or top face of the fabric only. One coat is usually enough. Really.
Pitch the shelter in good weather or the garage: somewhere where it can dry for most of a day. Pitch the tent or shelter tightly, as you would in the field. If it has an unusual shape that makes it impossible to seal all of the seams at once, do them separately on a different day.
Brush in the thinned mix carefully and use the damp cloth to mop up any spills. A little goes a long way. A cut-out template (shown above) will help reduce spills. The thinned mixture will soak in and look neat after it dries.SectionHiker is reader-supported. We independently research, test, and rate the best products. We only make money if you purchase a product through our affiliate links. Help us continue to test and write unsponsored and independent gear reviews, beginner FAQs, and free hiking guides.