(Re)Waterproofing an old tent?

[Clawhammer]

I got a great deal on a vintage "auto" tent. It's one of those jobs that attaches to the back of a van or SUV (or in my case, the back of a pickup with a topper) giving you a place to change clothes or whatever. I used it over the past weekend and I love it - more privacy, can stand up in there, a place for the dog to lay, it's great except for being a pain to get set up. It's from, I'm guessing, the 70's and seems to be well-made with some heavy duty poles and a thick, tarp-like floor. It has nylon sides and a canvas roof (no rain fly), which brings me to my problem....

The first time out with it, there was some very light rain one morning and the thing leaked like crazy! It seemed like the seams were leaking, but it may well have been that the roof is no longer waterproof and water was running down the corner seams. I had a can of that Kiwi Camp-Dry silicone spray used for boots and whatnot, and I sprayed some of that on the tent, but that was more of an emergency stopgap measure and I'd like something more heavy duty.

So my question is, what have you all used on old tents to make them waterproof again? I was debating using something like a Thompson's Waterseal on the canvas part, but wasn't sure how effective that would be. Anyway, I'd be interested in hearing anyone else's experiences before I do anything to my tent.

 

[kmlacroix]

Seam-seal

 

[jeep-N-montero]

If it is true canvas there are treatments that are made for it, some waterproofing treatments out there will actually damage canvas.

 

[Clawhammer]

If it is true canvas there are treatments that are made for it, some waterproofing treatments out there will actually damage canvas.

Interesting. I didn't know that. I would think, given the age, it wouldn't be true canvas, but rather a synthetic fabric that's canvas-y. I notice Cabellas sells a canvas waterproofer that will damage synthetic materials. Hmm... this might be a little more complicated than I thought.

 

[perterra]

Search around the Nikwax web site, they have some very good products

 

[jeep-N-montero]

Post some pictures or a model and we may be able to better help.

 

[Ducky's Dad]

I have used NikWax on old GoreTex jackets, and it is only marginally effective. Call some place like REI or River Sports Outfitters for advice. You might also get good (and relevant) info from a boat supply such as Jamestown Distributors or Fisheries Supply.