what costitutes "down-proof" rip stop???

**the_gr8t_waldo** · 03-10-2012, 13:10

i'm about to place an order for my TQ project. and after a cursory look at the sites, the rip stop 1.1 mat'l isn't identifyed as "down-proof". i'd simply hate to do all the work and then find out the mat'l i used wasn't holding the down! i intend to use 850-900weight down for this- not sure if this maters or not.

**JalapeñoBen** · 03-10-2012, 13:13

I think the term you're looking for is "calendered"

**DemostiX** · 03-10-2012, 13:44

Originally Posted by EastCoastFeastCoast

I think the term you're looking for is "calendered"

Would that were true.

Calendering -- heating and pressing and one side to make shiny -- is almost always the source of down-proofing, and with nylon the process seems permanent. But, there is nylon which is calendered (or looks it?) but not guaranteed to be / remain down-proof.

Go to Rainshed and learn, as they tell their customers, that downproof doesn't mean that it will retain synthetic fibers; only testing will reveal that. I know you didn't ask about that; but the point is the same: stuff needs to have its performance tested before a process can be assumed to yield a desired result.

**Ramblinrev** · 03-10-2012, 13:55

Originally Posted by EastCoastFeastCoast

I think the term you're looking for is "calendered"

It also makes a difference what the weave density is. You can calendar a looser weave for wind/rain resistance purposes ("resistant", not "proof") but it won't make it downproof. It also matters what fill power your down is. The lower the fill power the more quills and shafts there are to poke through. IMO you are best off buying from vendors who know what they are selling and specialize in outdoor fabrics.