Hello all
I am looking at a RSBTR topquilt kit as my first DIY project and was wondering if i would gain any warmth, especially in windy conditions, if i went with 2 layers of 2.5oz climashield separated by a layer of ripstop vs a single layer of 5 oz? 3 layers of calendered fabric should be pretty windproof but would it add warmth or just weight?
Comments please.
I just built a CS 5.0 top quilt for spring/fall, and after having slept in it overnight during windy, rainy weather, I'd think you would get diminished returns by splitting the weight of the CS into two layers with an extra layer of nylon fabric in between compared to building a conventional quilt out of 5-ounce insulation. Even if you use very lightweight fabric (like Argon 67), you'll still add nearly three ounces to the quilt win the third layer of fabric. Instead, build the outer shell out of slightly heavier, tightly woven wind proof fabric (my favorite is 1.55 oz Epsilon, although color choices are limited), insert a nice lofty single layer of Climashield Apex 5.0, and then line the inside with a second, lighter windproof fabric for extra protection against cold breezes. You have to balance wind-blocking versus breathability in a top quilt, whereas in an underquilt it's almos always good to have at least one calendared shell layer to block the wind. My $0.02. HTH...
No need for the extra layer of fabric, but doing a double layer of lighter weight batting is common in industry. This allows the variations in the batting thickness to cancel each other out. It also allow to offset the quilting lines (if you're quilting the material, to limit their impact to warmth. Most DIY'ers don't do this due to cost (it's often approaching down cost at that point), but it's arguably a better design.
The question of course it what's effective, and generally people are happy with their single layer quilts.
I was thinking that with 3 layers of "windproof" fabric, i'd have 2 independent dead air spaces, which would be slightly warmer in the wind, but i have no way to calculate such a difference. i can calculate thermal performance, but if i have to assume some level of air infiltration and heat loss by circulation thru the batting, then i'm in over my head./ and of course it's heavier. probably better off adding insulation rather than fabric.
Your idea of "two independent dead air spaces" isn't correct. The dead air space is in the pores of the batting. Adding a layer of fabric doesn't really impact how the insulation is going to work.
If you want to block wind, use a tarp/sock/undercover to block wind to the whole quilt. Think about it: adding a layer in the middle basically means you're willing to sacrifice the performance of half your insulation. That middle layer is better on the outside of your quilt. And also better as a modular system so you don't always have to carry it. Also, having an air gap between the "wind blocking layer (undercover/sock) will allow there to be a diffusing effect that reduces the air circulation directly against the surface of the quilt. That is if you even need that extra layer to begin with (circumstantially dependent based on where you camp, and the conditions at camp. I don't think I've ever needed it, personally)
Last edited by Boston; 10-31-2016 at 14:40.
looking at it another way, the middle fabric layer would prevent the 2 insulation spaces from "communicating" with each other. no air circulating from the cold side to the warm side. insulation by itself doesn't work in the wind. insulation + windproof layer works. I think it might be might be worth a side-by-side built&test. ...but it appears i will go with down anyway because the climashield TQ is going to be almost twice the weight for a 30F rating.... going by kitsap's numbers compared to an UGQ flightjacket.
Again, you'd be better off with all the "wind blocking" on the outside of the quilt. You're not really going to have any local air current inside the quilt.Originally Posted by Bikecop
I think you're over thinking this.
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