AnswerID: 183339 Submitted: Thursday, Jul 13, 2006 at 13:41
Member - Omaroo (NSW)
From: Campmor Tent FAQ
34. Can I waterproof my tent with a silicone spray?
Yes and no. Silicone can be sprayed on to improve waterproofing but can not be applied as a primary waterproof coating. When your tent is new the nylon or polyester on the fly, floor or walls has what is known as a Durable Water Repellency or DWR. This is applied to the actual threads and is separate from the urethane coating on the underside of the fabric. The DWR causes water to bead up and run
off similar to the wax finish on a car. As the tent is used or through age the DWR breaks down and allows water to stay on the fabric where it can seep through any breaks or abrasions in the urethane coating. Silicone renews the DWR so that water beads up and runs off before the water has a chance to find any breaks or cracks in the urethane. Silicone usually needs at least 2 coatings to be most effective but follow all directions with the product you are using. Silicone is to be applied to the outside or the uncoated side of the fabric; it will not work if applied to the underside or the urethane coating.
35. The waterproof (urethane) coating of my old tent is coming off. Can I recoat it?
You could, but it is a lot of work. By the time the coating comes off of a tent, the tent is usually in its advanced years (10-15) and maybe ready to retire. However, if you can't bear to let your old musty friend die, it is possible to recoat the tent. Most tents have the urethane coating on the under side of the fly and the inside of the body. First, the surface must be cleaned with a light soap solution (see above) and dried. Then all the loose urethane must be removed. Then, and only then, can you apply a recoat. Follow all directions on the product carefully. Whatever you apply will not be as good as when the tent was new as it is only a surface coat and the original was sprayed on under pressure. Good luck.
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FollowupID: 439866 Submitted:
Thursday, Jul 13, 2006 at 13:46
Thanks for that. Do you know whether it applies to canvas only or the polyester/nylon tents as well?
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FollowupID: 439874 Submitted:
Thursday, Jul 13, 2006 at 13:58
Member - Omaroo (NSW) posted:
Silicone applies to polyester in this case.
One other thing - there are seam sealands available in yubes that you brush into the seams of poly tents if that's where the leaks are coming from. Are you sure it's not a seam (up on top somewhere) that's leaking rather than the material itself?
Canvas tents are somewhat different. Canvas tents typically leak at the seams before they have initially been "seasoned". By "seasoning, I mean let the tent sit under a sprinkler (a tad illegal in some cities these days) or out in the rain during a heavy downpour or two. This will swell the stitching in the seams to close the gaps. It also lets the canvas fibres swell and close up ranks together. Canvas tents rely on the fibres swelling wen wet, and forming a level of surface tension. If you touch canvas when its wet it will leak because you break that surface tension. I have heard of solutions that you can apply to re-waterproof canvas, but remember that AUSTRALIAN-made tents use Australian canvas - which is arguably the best in world, and is waterproofed before the tent is made from it. Its "beading" quality of waterproofing usually lasts around 5 years of decent use before you are back to relying on swollen fibres and surface tension again.
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