$12.00
Gear Aid Seam Grip +SIL Silicone Tent Sealant
Specifically designed for silicone impregneted fabrics this is the stuff you need for sealing silnylon tents, tarps, dry bags and ultralight packs. One tube can seal up to 24 feet of seam. It's also great for sealing small pinholes or tears and provides a flexible, waterproof seal that last for years.