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Seam sealing an older tent - been sealed before

4:57 p.m. on October 6, 2008 (EDT)
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I have a North Face tent that is 15 years old...still is awesome shape. I originally had seam sealed the rain fly seams but have noticed now that even with just heavy dew, there are some drops on the tent. I want to re-seam seal the fly.

I do not recall what I used 15 years ago, but the inside of the seams are shiny...probably a silicone type?

Thoughts on the product I should use?


5:31 p.m. on October 6, 2008 (EDT)
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You probably used McNett's SeamGrip or Kenyon SeamSealer. Both work reasonably well for re-sealing the seams on tents and waterproof/breathable parkas and rainpants, IF you follow the directions on how to clean and prepare the material, and IF you follow the directions on where the goop goes and how to put it on. Too many people just apply the new coat over the old coat, then find that it continues to deteriorate rapidly, since the old coating that was simply painted over is actually deteriorated.

Both these products are formulated for putting onto synthetics, while a lot of other "sealers", especially the silicone ones you find in the hardware store, have solvents that will dissolve nylon and polyester that is used for rainflies and clothing. Whatever you choose, be sure you test it on a corner of the material to be sure it is safe to use on that fabric.

8:43 p.m. on October 6, 2008 (EDT)
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I will check the instructions when I buy the sealer.

Sounds like quite a job to clean the old stuff off...hopefully it is a cleaner that just removes whatever is 'old' etc.


10:36 a.m. on October 7, 2008 (EDT)
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I found SeamGrip at a local retailer. I have some concerns as it says to not use it on Silicone....I do not recall what I seal these seams with back in 1995 timeframe. The seams (on the inside of course) are glossy and a tiny bit tacky. Is this what SeamGrip appears when dry? SeamGrip says to not apply on Silnet or Silicone. Was SeamGrip around in 1995 timeframe that I could have used it?


12:15 p.m. on October 7, 2008 (EDT)
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SeamGrip and SeamSealer have both been around for over 25 years, and I think I first started using them close to 40 years ago. Both of them, being basically a plastic dissolved in a solvent, look like a shiny, thin plastic film when they dry, much like the coated side of a plastic poncho or most polyurethane coated rain flies. The reason for recommending against using them on SilCoat and other silicone-coated fabrics is that the silicone-coated fabrics actually coat the individual threads that are woven to form the cloth. So the seam sealers don't stick very well.

Your TNF tent fly is NOT SilCoat. Virtually no manufacturers made use of SilCoat or other silicone fabrics for tents or tarps before 2000 (with the notable exception of Integral Designs, who pioneered its use - yet another reason to get gear from ID, with them being so far advanced over others and really knowing how to use the new materials). There are no worries about using SeamSeal or SeamGrip on your ancient TNF fly. It was, in fact, the recommendation by TNF (and most of the top-quality tent manufacturers). IIRC, TNF used to include a tube or bottle of one of these with all their tents at that time. Which is probably why you coated the seams at that time.

6:43 p.m. on October 7, 2008 (EDT)
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I have a mid 90's Mountain Hardware Tent, it came with a tube of Seam Grip and instruction. My fly is still watertight to this day. I understand that most tent makers offer tents with factory taped seams now.
I have been looking at an ID bivy to take snowshoeing this winter, they do seem to have an impressive product line and I am quite interested in their products with the Event material.

1:10 p.m. on October 16, 2008 (EDT)
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Using GE Silicon II (common in hardware stores) works with silnylon and many other slippery material.

Make sure the seem is clean and free of the old sealer. You could use Ethanol (from the same store) liberally on a cloth to scrub it - careful it is flammable and the fumes are toxic. Best to be done outside in a non enclosed environment. Best to turn the tent inside out for this cleaning.

Using a CLEAN tuna fish can, fill it 1/4 full with odorless paint thinner (same place you get the Silicon II). Add Silicon II until the can is 1/2 full (50/50 mix).

Stir until it has mixed thoroughly. This may take a few minutes but keep stirring adding patience as needed. You will have a pot life of about 1 hour. If it starts to thicken, clean out the can and start anew.

Set up the tent taut and in the shade. A public park makes a great place if you are careful where you set it up. You will now be getting very close and personal with your tent. Quality time coming up. Nice radio station and a favorite beverage if a hot day helps.

I like to use a 1" cheap brush (get it while picking up the paint thinner) and cut off about 1/2 the bristles. This gives you a fairly stiff applicator.

Or use your finger making sure that any seams and sewing holes are well filled. Use it sparingly and work from a corner out. Use large boxes inside the tent to keep the seams from coming in contact while it cures.

The more moist or humid the air, the faster it will cure.

2:03 p.m. on October 22, 2008 (EDT)
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How about Thompson's Water seal? I've had real good luck with it. First time I gave it a water hose test -no leaks, then and none so far.

9:07 p.m. on October 22, 2008 (EDT)
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5,186 forum posts

Thomson's is ok for waterproofing tents (especially canvas tents), but is not for seam sealing. It does shorten the life of many fabrics, though.

April 20, 2014
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