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I have a ProForce All Weather Shelter, which is listed as being "210T rip-stop nylon". On a recent outing, we had four hours of rain overnight and it leaked on me the entire time.

Upon closer inspection, there are areas where the fabric appears to have either worn thin or has lost some sort of coating (see light splotches in the fabric below):

enter image description here

I've had this tarp just under a year, and it's probably been used a total of 20 nights. For what I paid, I don't want to replace it so I am looking for a way to restore the water resistant qualities.

I am aware of the spray-on type of waterproofing typically available at stores such as Walmart, but am not convinced this is the best option. Are there other alternatives?

  • PU won't stick on silicon (PU foam + acetone). I tried, you can remove the coating with the finger. – JinSnow Mar 12 '16 at 13:51
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This addresses the perfect solution for silnylon. http://jwbasecamp.com/Articles/Silnylon1/index.html

Or if you are wanting to continue with instruction that specifically discuss PU coatings there is this: http://dzjow.com/2012/06/18/how-to-re-coat-a-shelter/

The processes are identical, one just cites one specific kind of material while the other offers a more general application base.

In case of page deletions here is a brief summary of the information:

Shelters made out of cuben fabric never need re-coating. All other fabrics do have a coating which will degrade over their lifespan, mainly due to rubbing, the degrading effect of UV light from the sun and storing it wet. Shelter fabrics usually have either one of those two coatings: a silicone coating or a PU-coating (polyurethane). Tent floors usually have a PU-coating while tent flysheets usually have a silicone coating. However, a PU-coating is still used by some manufacturers on their tent flysheets. It is important to know which kind of coating has been applied to your shelter as each of these two kind of coatings need another product and solvent for re-coating. Some tents like for example those of MSR even have a different coating on each side of the fabric of the tent fly, a silicone coating on the outside and a PU-coating along the inside. If you’re not sure about the type of coating, try to contact the manufacturer.Coatings based on silicone are the easiest to renew. In case of a PU-coating it is more difficult to find the right product and solvent.

Ok, what do you need?

These are the necessary items for a silicone coating:

White spirit A tube of silicone: transparent and odorless (without additives) A silicone syringe A clean pot or jar An accurate weighing scale (one gram accuracy recommended) A paint brush A pair of protective gloves (you’ll notice I didn’t wear gloves but you should know better)

For a PU-coating you’ll need an urethane based product and an appropriate solvent. One can also try the expensive option like Tent Sure Tent floor sealant from Mcnett or the Nikwax variant. Otherwise the method for a PU-coating will be rather similar as I’m going to explain for a silicone coating.

1.Pitch the tent in a well ventilated area, preferable outdoors(on a sunny day). If weather conditions cause a good bit of dust and debris to carry in the air wait, or move indoors. While minimal dust will not affect the quality of your application large particles (like the neighbor mowing) will affect adhesion.

2.Clean to prepare fabric for coating. Make sure that fabric is completely dry before attempting to recoat.

3.Prepare mixture:
Pour white spirits(15) and silicone(1) into a jar (weighing) the components so that there is a 15:1 ratio. As a general guideline try to using a 1.5g/1 sq. m estimate when purchasing materials. Consider each side of your tent/tarp an independent area if you are going to coat both sides.
Stir until spirits and silicone are dissolved.

4.Paint mixture onto fabric ensuring that no runs or drops gather on the fabric. Once dried touch the surface to determine if coating is thick enough. IF necessary apply another coat. Some minor discoloration may be noticed due to operator errors. (Who can perfectly and evenly paint that kind of surface?)

5.After you are confident the tent is 100% dry test the coating with a spritz of water. If the water beads and runs off you have succeeded. If not repeat steps 1-5 again.

  • 2
    Applied the first (silnylon-specific) solution today, and things appear to have gone fairly well, though I am still allowing the tarp to cure overnight. I diluted the silicone with odorless mineral spirits in a 1:3 ratio (by weight). For those who are curious, I used a total of 360 grams of solution -- 270 grams mineral spirits plus 90 grams GE silicone sealant (purchased at Home Depot) -- with a 4 inch dense foam roller to treat a 10 foot by 10 foot tarp. Note that I only treated the underside of the tarp with this amount and not both sides. – Jeff W Aug 2 '15 at 2:59
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    I gave the tarp a once-over after being allowed to cure for two days, and the sealant is firmly attached. The surface has a nice, rubbery feel to it which APPEARS to be both durable and waterproof, though I have not yet hosed the tarp down with water to test this appearance. Overall, the treatment added 2.2 ounces to the 10x10 foot tarp (with stuff sack, weight increased from 1 lb 11.0 oz to 1 lb 13.2 oz). – Jeff W Aug 4 '15 at 1:44
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    I had the tarp out in the yard today during a (nearly) three hour steady rain, and it held up much better than I had expected. At several points during the rain, I ran my hand over the fabric on the bottom of the tarp and was unable to detect any substantial moisture. There was certainly nothing visible at any point. I do believe that the tarp is more suitable for use in wet weather now than it was when I first purchased it! I would highly recommend this process to anyone considering it. – Jeff W Aug 31 '15 at 2:52
  • Awesome. I am thrilled your efforts were successful. – Charlotte Rose Hamilton Sep 2 '15 at 8:11
  • any idea of the toxicity of the mixture (before it dries out / polymerization)?Any dangerous gas or compound in the liquid? (For instance the PU+acetone is only toxic when applying, since isocyanate can penetrate the skin, but it doesn't emits really toxic gas) – JinSnow Mar 12 '16 at 13:51

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