I just recently and serendipitously stumbled upon the concept of using open celled polyurethane foam for extreme cold temp use, as well as possible exposure to water. There’s a bunch of youtube videos where people wearing foam clothing jump into holes in frozen over lakes, into streams, etc while it’s cold outside. One guy, ended up going in like 2 more times after the initial time because he was warming up so fast in the foam clothing. As soon as the water started to drain out of the foam, they would start to feel warm again (and it apparently drains fairly fast, especially when squeezing or wringing it out).
The guy who pioneered and brought the concept to the public the most, Jim Phillips, extensively tested it and compared it to traditional insulation’s used for extreme cold. Apparently, its far superior in some ways–mostly in it’s ability to handle moisture and keep a person warm and comfortable in a wide range of temps and conditions. He says it’s very important to line it with very breathable, but quick drying fabrics. A lot of the little companies that sell foam clothing, line either the inside or outside with a heavier duty mesh to allow it to breathe the most.
Course, like anything, it has some downsides–mainly it’s bulky and a bit heavy (though that somewhat depends on the density of foam being used and the fabrics lining it). Some of the open celled foams aren’t that durable also, so you have to research which ones are more so.
Jim sells a “special” version of the foam on his site, which is pretty pricey. He says that it’s superior to other foams in various ways, especially in resiliency, compressive recovery, air permeability, and overall durability. Doing a little digging, i think what he is selling is most likely a lower density “Dry fast” foam, which is more expensive than a lot of other open celled polyurethane foams, but he’s marking it up some 200% (or more if he is buying it in bulk).
Some folks use it for everything, including sleeping gear. I’m not sure i would go there because of the weight and bulk (well i would with using a Pulk or Pulk-Shelter), but making some clothes with it sounds pretty interesting and worthwhile if one plans to go to the Arctic or Antarctica. It seems like it would be especially advantageous to combine it with fishnet baselayer that has some Merino or especially Alpaca in it to help cut down on odor some, because i can imagine the foam getting pretty rank after awhile especially when right next to the skin.
A handful sources so far, say that to sew the 1 inch thick stuff (the thickness needed for Arctic like temps, except for feet which needs 1.5″) is nigh impossible with a regular sewing machine and you need an industrial machine. 1/2″ is ok to sew with a regular sewing machine these same folks say.
Anyways, any BPL folks who have used or know people who use it, and if so, what kind of foam? I ask what kind of foam, because even within the open cell polyurethane foam category, there are various different versions. I’m really surprised i haven’t heard of this earlier. I briefly thought about using open celled foam before, but i assumed it would hold onto moisture too much. I do think that needle punctured closed cell foam could be an alternative since it’s warmer per weight, and some kinds (like Evazote) are much tougher than most of the open celled foams.
