Hello, I bought a montane slipstream made of pertex quantum. I thought that it was waterproof, and it seemed so until I got caught in a torrential downpour and i got pretty wet.

I can't say for sure, but it seemed to me that the water snuck through the seams.

Does anyone have experience with seam sealing a montane slipstream or pertex quantum, and have pointers for best practice?

Thank you!

The water did come through the seams. And everywhere else. The Montane Slipstream Jacket is not waterproof (I hope it isn't advertized that way). A 3-oz waterproof jacket with the breathability of pertex quantum would turn the outdoor industry on its head. Goretex would disappear. Your jacket is a windbreaker, not a rain shell. Pertex quantum is just nylon fabric with a DWR (Durable Water Repellent) coating. Mist or drizzle will run off due to the DWR, but real rain will go right through it. It is used for windbreakers and the shells of down-insulated articles (sleeping bags and jackets).

Read the labels (or do some background reading) before you buy. Pardon the scolding tone, I'm just saying it's cheaper to be an educated consumer.

Edited by ckrusor on 08/30/2010 17:22:45 MDT.

> The Montane Slipstream Jacket is not waterproof (I hope it isn't advertized that way).

Montane certainly don't advertise it as waterproof: it's in the 'windproof' section of their website.

There is/was* a Pertex Quantum Endurance fabric, with the Endurance PU coating, but this was only marginally waterproof (1000mm HH). And isn't used in the Slipstream...

* it's a bit hard to keep up with the Pertex range since Mitsui took over, and juggled the brand names about a bit, and introduced new fabrics.

> A 3-oz waterproof jacket with the breathability of pertex quantum would turn the outdoor industry on its head.

;-)

Thanks for the thoughtful and educationally thorough reply!