MacEntyre kindly sent me a sample of Insultex.
To reiterate what has been posted in other threads, it appears to be a thin (0.5 mm) sheet of polyethylene foam sandwiched between two layers of spun-bonded scrim (for strength, I think), all three layers sewn together with a diamond shaped quilt pattern, with the needle holes presumably making the otherwise impermeable foam layer somewhat breathable.
Last edited by Albert Skye; 08-17-2010 at 18:13. Reason: Macentyre -> MacEntyre
In addition to the quilting needle holes, it is 'micro perforated' generally. You can see the holes if you make a small pocket of water and squeeze it. Water will shoot out the micro-perforations.Originally Posted by Albert Skye
Maybe... I don't think anyone has tried it.
Seems reasonable...
IX does not do well when compressed, so it won't work well on the ground.
Send a PM to Stormcrow.
- MacEntyre
"We must, indeed, all hang together or, most assuredly, we shall all hang separately." - Ben Franklin
www.MollyMacGear.com
How much of an air gap between layers does IX need?
hammock [ham-uhk] noun
Man's successful attempt to sleep on a cloud
Very, very little. I use pleats of any size as standoffs.
More in keeping with the topic, I am experimenting with combining three different things with IX. I'm going to make three IX Inserts 3/4 size using 1) my last Thermadrape, 2) a Heet Sheet and 3) a space blanket. I'm trying to decide whether to put these reflective vapor barriers between the outer cover and the IX, or between the IX and the hammock. Conventional wisdom says to put the vapor barrier right against the hammock, but I'm not certain that is best when used with IX.
Last edited by MacEntyre; 08-17-2010 at 08:49.
- MacEntyre
"We must, indeed, all hang together or, most assuredly, we shall all hang separately." - Ben Franklin
www.MollyMacGear.com
How 'bout putting a layer of no-see-um meshVery, very little. I use pleats of any size as standoffs.
hammock [ham-uhk] noun
Man's successful attempt to sleep on a cloud
As I said earlier in this thread, my feeling is that the mesh should be both an insulator and a separator. No-see-um is only a separator, so it's weight comes with less benefit.
- MacEntyre
"We must, indeed, all hang together or, most assuredly, we shall all hang separately." - Ben Franklin
www.MollyMacGear.com
I used a small piece (one of the diamonds cut to remove stitching and scrim) but I did not see any water leakage. As it appears to me, it is essentially impermeable, and it behaved as the several samples of PE/PP foam sheet used in shipping applications which I also tested.
I've seen a diagram of Insultex which depicts a membrane layer next to the foam but I see no indication of that in my sample. It appears to be simply a sheet of ordinary PE foam sewn sandwiched between two layers of scrim.
Squeeze!
Their diagram appears to be an application of Insultex, not a diagram of the material itself. I believe it's a schematic of Arctic Armor apparel.
- MacEntyre
"We must, indeed, all hang together or, most assuredly, we shall all hang separately." - Ben Franklin
www.MollyMacGear.com
Assuming a construction with two layers of foam, each layer can be made either with pleats or quilt-like seams with the objective of orienting the two layers such that the rough sides are facing each other and the the protruding seams or pleats contact each other perpendicularly to minimise contact area.
Advantages of quilt-like construction:
- a large area can be composed of smaller pieces (such as those readily available in the waste stream)
- a cut edge seems likely to have less thermal coupling than a folded edge
- better separation may be achieved if each layer has seams at right angles
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