Variation on Daryl’s theme (in c minor), Foam vests meets Fishnet concept.

So I saw what you did, liked it, but thought, "Man! that's a lot of holes to cut out!"

You know what expanded metal is, right? Sheet metal is cut with slits and pulled to create an open-weave metal material. I suspect a similar process is used to create the low-density foams inside of modern thermarests and other self-inflating pads.

Do it yourself: slit a sheet of open-cell foam (maybe after bonding it to a light nylon fabric). Then stretch it around your trunk – the gaps will open up.

On one line, cut a 2" slit centered at 2", 5", 8", etc. So you've cut from 1 to 3, 4 to 6, 7 to 9, etc.

Then offset that 1.5 " for the next line.

Alternate down the sheet.

It would be very flexible in covering your torso which isn't, you may have noticed, a perfect cylinder.

Make it over-long because when you stretch the width, the length will decrease.

Hi David,

Thank you for the idea, i may do that with the next one i make. Re: attaching/bonding the nylon, do you mean in the back and to the sides, sort of creating a pull over shirt?

Also, i can see where this will save some labor/time, but how will it save, or improve weight? There will be more material, both foam and with possible added fabric so it will likely weigh more.

A general note:

With the first prototype, i first started out by cutting squares and did so with my fiskars rolling fabric/craft blade (sort of looks like a pizza cutter), but then i switched to longer thinner cuts. Found the latter was much quicker, but got a little overzealous and made some too long (which is why i decided to tape in the middle on one of the overly long slits). This foam is tough and flexible, but it's not fabric and doesn't have the tensile strength of even wool, so i have to be careful with how much pulling force i put on it, and thus also have to be mindful of how long, wide, and spaced apart the slits are.

Just,

I like the idea. With a windbreaker over it seems like it would trap a good amount of warmth……but I haven't tried it. I really like how light it is.

David,

Good idea on the expanded metal concept. Some of the papayas sold at the store have a foam jacket with slits. It fits the papaya nicely and since the papaya and I share a certain similarity, shape wise, the idea should work on me.

oh goodness, get thee a hole punch.
avail int he Osborn brand at industrial supply places and in the useless chinese caca version at harbor freight.
you can punch thru foam easy as pie. use something like UHMW as a backing plate, and your punch will last a very long time.
you can get Osborn punches in some jolly big sizes.

you've got going there a great idea ! maybe slab it between a windshirt and a merino top.

v.

How about combining your original idea of polypro cord on shirt and foam vest?

Those foam strips are available from hardware stores if you prefer round cross section over rectangular.
More durability and better fit than in foam only construction.

I think vertical strips could work better than horizontal. Stretch is needed more in horizontal direction plus you maybe want to cut down the wind (that wants to flow around you in horizontal direction) and encourage the chimney effect (that cools you down with vertical flow)

Yes, I believe a non-water absorbing mid layer is a huge improvement to clothing in tough conditions and have heard others think the same. Just takes an explorer mind to wade through the early crude prototypes So go for irt!

Hi Daryl,

Thanks. If you do happen to try it out, please let me know what you think.

Arg Peter, not more stuff. Well, if i thought i would need it for other things, i would probably get the kind of hole puncher you're talking about. But i don't want to get it just for one project.

The fiskars rolling blade makes quick work of it, if you do longer slit type holes. Admittedly the nice neat squares/rectangles was taking awhile.

Yep, i plan on doing something very much like that. Merino synthetic baselayer, foam as mid layer and then wind jacket.

If it's unusually cold, then throwing in fishnet shirt, and a thin silk shirt also might help. Or the Pat. Cap 4 hoody.

Hi Alpo,

Hmmm, that's something interesting to think about. A few considerations need to be addressed first. The way you have it set up in your pic, you would either need more vertical foam or some cross horizontal pieces to get the true "fishnet" effect because what's going to happen in the above set up is that the fabric on the outside (presumably a wind shirt or jacket type fabric) will tend to fall into and billow out from the overly wide depressions. Will severely reduce and disturb the still air which is what is creating the insulation to begin with. Should still keep the outer layer dryer than it normally would be, but you won't get as much insulation.

Also, i'm not sure about this, but i tentatively think the fishnet insulation effect i think has a limited depth/thickness of air that it will work efficiently and effectively at. More than a centimeter or so, it will probably begin to lose efficiency. Hopefully someone with good insulation knowledge and experience will chime in on the above.

Types of foam: The Evazote foam is particularly good for this kind of application because it's very flexible, tough, stretchy, durable and light weight. If i can find something similar or equivalent, in the tubular rolls as pictured above, i would be very open to trying the above (provided they are thinner). More common, and inexpensive type foams tend to be more stiff, and won't pack as well. Volume is a definite consideration for me.

>"More than a centimeter or so, it will probably begin to lose efficiency. Hopefully someone with good insulation knowledge and experience will chime in on the above. "

Good estimate. The sweet spot for double-pane windows is between 1/4" and 1/2". 1/4" is a little below ideal, but of course a little slimmer. 1/2" is better but not by a lot. More than 1/2" and convective movement starts to reduce the R-value. I'd expect similar effects in fishnet.

Thanks David, didn't know that, was purely intuitive guessing on my part. Thinking about it some more, though, kind of wonder if perhaps a smaller gap might be more efficient since we're dealing with not two layers of non porous/non breathable glass, but rather 1 layer of fairly breathable material (wind jacket) and one's skin (which produces heat and vapor, which will create convective air currents itself to a small extent)?

I don't know, just throwing it out there as i'm want to do.

Good points Justin and thanks for the insight David.

Need to visit a harware store… remembering we probably want not the highest possible insulation, but the smallest possible difference between dry and wet insulation. Sounds like a small surface area.

Justin, you should seriously consider a career in the outdoor gear industry.

Justin, thanks, that's kind of you to say. The idea has occurred to me before, but judging by the typical responses (often a lack) i tend to receive here about a lot of my ideas, not sure if there is much market out there for my kind of thinking.

Also, i know i would be a horrible businessman, and financially it's likely a disaster waiting to happen–i'm sort of anti capitalistic and materialistic to an extent, and that's not good for maintaining a business.

"remembering we probably want not the highest possible insulation, but the smallest possible difference between dry and wet insulation. Sounds like a small surface area."

Good point, and speaking on average i agree. But there may be times when someone might want or need the highest possible insulation for lowest weight while having great moisture control all at the same time.

Some of this recent line of thinking on my part, has been spurred by my desire to backpack the Brooks Range in Alaska in late winter/early spring time eventually. Course, i would test out the gear before going to a more extreme climate. While not afraid of death, i don't have a death wish.

"but judging by the typical responses (often a lack) i tend to receive here about a lot of my ideas…"

for every response there are many readers

one person's idea, even a bad or ridiculous one, often stimulates other ideas

there is no such thing as a bad idea. No idea is bad.

Really interesting thread. I keep popping in to read more about the vest's development. Learning a ton about insulation.

"However, good quality fishnet shirts tend to be expensive and there is a small market with little competition, with most of the companies being in Scandinavia region."

That's because fishnet shirts are not called fishnet shirts the world over.
If you haven't already, search for "string vest" or "string shirt" and you will get more options. String vests used to be really popular here in UK a generation ago.

"for every response there are many readers"

Jerry,

Good point. Another website I visit shows the visits and it is often quite high even though the responses are low.

Just,

My posts typically get few responses too. I'd hate to depend on selling my ideas for a living.

" Arg Peter, not more stuff. "

well .. yeah, more stuff. but not deplorable gizmodic, ignoble in all regards, and devoid of value stuff. but good, clean, honorable, "lets you do better work" .. stuff.
because you see, there's a difference.

Davids idea of the slits is better. if the material is not prone to tearing. the holes are better if the material is tear'y, because you get a bit of stress relief based upon the shape.

maybe don't worry about extra tooling. what you think you're going to save in tools will be more than exceeded by the excess scrap rate of failed attempts to do things "the easy way".

good hunting,
v.

Air-pocket insulation is the reason why traditional North Atlantic knitters took the time to make those cables and bobbles in fisherman sweaters and Aran knits (the decorative art followed the practical necessity, as it often does, and thank goodness).

They got more warmth for a given weight of wool, in customizable panel form (i.e. thick cabling on the front of the torso, with a finer textured stitch under the arms). The braiding creates fabric depth and holds air pockets in place. It's also a giving and elastic structure.

This thread has me imagining a vest with panels composed of braided foam strips. Thin foam, broad (8 strand?) braid. I bet it would work! Thanks for the interesting idea, Justin.

Hey there Justin, I had an idea a while back that was similar in concept, but different in execution, to yours. My idea was to attach foam spacer dots to a slightly oversized outer shell. The concept being to create an air gap using cc foam. I never did put it together. Anyways there were some comments you might find useful.

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=54760&skip_to_post=462063#462063

Or you could have "dots" of synthetic or down. Or "lines".

Or insulation on your shoulders, a line around the top of your chest, and a line around down below – whatever it takes to keep the inner and outer fabric apart.

I always though foam net laminated between solid foam could make a lighter foam pad. Spaces more than 1/4" develop air currents from convection that overcome the insulation value. Especially in clothing where you are moving and flexing.

Fruit pakcage plastic expanded PE Foam Fruit Net Making machine, PE foam mat making machine, wine bottle net making machine
http://www.alibaba.com/product-gs/698691158/Fruit_pakcage_plastic_expanded_PE_Foam.html

http://www.alibaba.com/showroom/pear-net-foam-making-machine.html

I was at a Maker Shed last week and one of the brainstorming sessions was how to monitor the output of a foam packing peanut machine, keeping the corn based material the right consistancy so the peanuts would be uniform coming out of the extruder.

i wonder if you could make whole extruded parts-a sleeve, a collar, etc.

Also wonder if you could make bio-degradable corn based clothing.