Ideas for adding low bulk, low weight insulation to tent

[Anonymous]

First throw away post.

[Anonymous]

I’ve been thinking of ways to add warmth to a tent (MLD Solomid) for winter backpacking. Unfortunately, most ways are either heavy, or bulky (lightweight CCF foam). Bulky is ok if I bring a pulk, but I like to explore various options in any case.

Think I may have a solution to the bulky and weight part. Suspend/mix Aerogel particles like this, http://www.buyaerogel.com/product/lumira-aerogel-particles/

or this; http://www.buyaerogel.com/product/enova-aerogel-ic3120/

in a silicone slurry and coat some Membrane SilpolyPU4000 fabric on the primary silicone side. Do a couple of layers. On same side of the Aerogel coated one, take thin foam strips and create a loop and strategically adhere to same. Just enough to create some air space.  Over that, put mylar space blanket, and over the space blanket goes nylon tulle.  The space blanket/nylon tulle side would be facing away from the tent fabric and facing the person in the tent.

When you pack up and compress the tent, the foam loops will fold over/collapse, but when it’s set up, they will pop up creating air space in back of the mylar space blanket. These need air space on both sides to reflect IR. (The foam will provide a little more protection to the Aerogel particles/coating when it’s packed up/compressed too. Hah, 3 birds, one stone).

The combo of above materials, will be velcroed to a MLD Cuben Solomid.  I guessimate the combo fabric/material to weigh somewhere around 4 oz/yd2.  I’m just not sure how much the silicone + Areogel particle coating will weigh. The silicone will have to be thicker than usual, to help protect the Aerogel particles which are brittle and fracture fairly easy. Silicone is a decent matrix for it.

I know one of the above products is made and sold specifically to be mixed with paint or other coating materials to increase insulation. I’m not sure about the Lumira stuff though (it’s a bit cheaper). It does have a hydrophobic coating. I just recently contacted the company that sells it and asked them about it being mixed in a paint thinner/silicone adhesive blend.

I’m not expecting miracles, but to add just enough insulation to make things more comfortable on those polar vortex days of near 0* F or below temps. I’ll be bringing a couple of medium sized beeswax candles primarily on weekend trips, both for light and a little extra heat. Will also provide a nice light show with it reflecting off the space blanket. With 3 impermeable fabrics, Aerogel+thick silicone coating, a little extra air space from the foam strips, and an IR reflector there should be a noticeable boost of insulation.

The door and peak of the tent will be covered with some Apex lined with ultra breathable, UL materials, for maximum breathability.  The idea is that I can open up the door some, but still have some insulation + ventilation. Plus there will still be some draft from the bottom.

The tent itself should stay under 3 lbs, and be fairly low bulk.  Low enough to put in a large, voluminous pack, and not have to bring a pulk (I primarily do weekend trips in Winter).  On a side note, I’ll probably spray the outside of the Cuben tent with a DWR to make it more slick for snow.  Can’t imagine that the DWR coating would last long though.

Just not sure how much Aerogel particles I will need though? The affordable volume they tell is 1L and .95L, 68 and 55 dollars respectively. Do you think 1L will be enough for two coats, or will 2 or more Liters have to be purchased?

 

 

[Jerry Adams]

tent has maybe 12 square yards

quilt has maybe 3 square yards

better to put your insulation next to you

the space blanket only works if there’s an air space next to it.  It would work twice as good if there was an air space on both sides.  Suspend the space blanket from the tent on the inside.

[Anonymous]

Hi Jerry,

Yes, it’s very correct that putting insulation next to you is much more efficient weight/volume wise. Most of the backpacking I do, minus an occasional, longer, traveling trip in the Summer, is in the colder seasons and weekend trips, when the days are short and nights long (and full of terror–at least after a big bowl of chili is ravenously consumed…).

I’ve been out when it’s -5*F and have thought then, gee, wouldn’t it be nice to have a tent that is somewhat insulated and I could just burn a couple candles in and stay significantly warmer than outside?  Long story, but on these weekend trips, especially in the dead of winter, I often end up doing a lot of lounging, cause I try not to hike in the dark when it’s slick or slippery out and tend to get a late start (night owl, 2 hr drive at least, spouse, working 2nd shift, etc).

If I can add significant heat retention without much weight or bulk, then why not?  Especially since it won’t permanently be on there, and I can save it for the truly cold days/nights.

  “the space blanket only works if there’s an air space next to it.  It would work twice as good if there was an air space on both sides.  Suspend the space blanket from the tent on the inside.”

Yep, that’s why earlier I wrote that there would be air space on both sides.  With the little, thin, upright foam loop strips, I’ll make it so there is about a half a inch of air space behind the space blanket.  On the front of the space blanket will be nylon tulle which is very open weave. It still should reflect plenty of IR back.

Suspending it would work too, but I’ve tried that previously and it’s harder to do well than it might seem, as far as getting the right tautness and not using up too much space. Because I’m short, I have some extra space in the Solomid, but not a lot. I like the ease and convenience of just velcroing on, all one connected material sandwich.  (Which I would do at home, before getting out there.)

All the folks who primarily backpack at 20*F and above, probably think all the above is crazy, but when it starts getting below 0*F, it becomes a little more attractive of an idea.

It’s also meant to fit in with my prepping gear/plans, and will be a bug out bag item should the need arise. A tiny little wood cooker stove like the below one:

would then become VERY efficient at warming the Solomid and drying out stuff. But for regular backpacking trips will just use a couple of beeswax candles.

 

 

[Matt Dirksen]

Hey Justin,

Koodos to you if you can make it work toward insulating a tent.

Albeit expensive, it seems clear to me that Aerogel will find it’s way into the outdoor equipment world, it’s just a matter of time. (I assume you’ve looked at Oros by now)

Given that it’s got the highest R value of any material by a long shot, even a thin layer of it could make a measurable difference. Perhaps you should reach out to this company and see what they have to offer.

But putting that all aside, it’s crucial to remember that any heat retained in a tent, will very quickly be replaced cold air, if you can’t properly balance the heat (and moisture) gains with just the right amount of ventilation. In my daytime profession (architecture) I often share the analogy with clients that: “A one square inch of an air gap is about the same amount of heat loss as an 8 foot un-insulated wall”.

My most delightful winter base camping trips were always using old-school, 3-5 person double walled tents, with lots of mosquito netted windows protected by nylon door panels. I believe the combination of fully closeable panels and the mosquito netting, helped the tents retain heat well, while allowing for multiple ways to adjust ventilation.

Given the impact of air convection on heat gain, you need to have complete control over the right amount of ventilation, for any of this to work. If you restrict the airflow in your tent too much, you will run the risk of condensation issues. Too much ventilation and you will never experience the heat gain you are seeking.

Good luck!

Matt

[Anonymous]

Hi Matt,

I wasn’t aware of that outdoor company, thanks for the link. Agree that it’s a tricky endeavor. I’m “hoping” that I can get most of my ventilation from the super breathable Apex panels at the door and over the peak vent.  I’ve made Apex vests that are so air porous that they offer very little resistance to breathing in or out of same, at least.  Granted the insulation factor will go down, but it’s better than having a completely open area with no insulation.

I think it’s worth experimenting with and trying out. It may not be as expensive as it may seem. Tulle’s cheap, Membrane SilpolyPU4000 was on sale when I bought some, space blanket is cheap, silicone is cheap, velcro is cheap, cuben tape relatively cheap.
I’m also in contact with a China based company (via Alibaba) that sells Aerogel particles (with and without hydrophobic coatings) in low volume/weight orders for 60 dollars per kilogram.  I’m waiting to hear back on how much volume does a kg of this material take up.

Thanks for the other link as well, I’ll check it out.  And more over, thank you for expressing the Socratic method (open minded AND skeptical)!  It seems a bit rare round these parts. ; )

[Matt Dirksen]

You’re welcome, Justin.

Just recognize your ideas are entering the realm of true BPL now. (Backpacking Luxury)

;>D

[Anonymous]

True that. I’m a minimalist on regular 3 season type trips, and generally practice the concept that lighter and less is better. But when it comes to those 0*F and colder trips, I wouldn’t mind a little Luxury…

I have and have used a hot tent set up—the full deal (large, tall tent, titanium wood box stove and pipe, etc), and I’ve found they are a lot of work.  Plus, I bought the stove before I knew that many forms of Ti have a problem with getting brittle the more you burn in it. So I’m kind of saving it for when I might really more so need it.  What I DO really like about the conventional hot tent set up though, is how efficient they are at drying stuff out.

[R]

How ’bout you set out for a night w/ enough sleeping bags to line the walls of your tent and see what kind of difference it makes.  If you know the temp ratings on the bags, or loft and insulation type, you should be able to get a good sense of what your specific performance goals are and what can be achieved w/ conventional materials.  If those figures are way off the mark, then you should plan on investing some time in developing your DIY aerogel coating.  If you don’t know the performance of your coating, you’ll be shooting in the dark.

Do you have reasons for ruling out more conventional insulation such as down or Apex?  If you keep your vapor barrier inner, you don’t have to worry about condensation accumulating in your insulation.  You might consider a multi-wall tent (3 or 4 walls?) w/o any insulation but the air gaps.  Or a baffled air gap as Thermarest uses in their NeoAir mattresses.  Any of these can be well under 4osy and compress fairly well.

[Edward John M]

4osy ?

Nice to see you start the thread here.

Even a layer of No-See-Um mesh can have an insulating effect by slowing down the flow of air. Thought experiments here :- Space filler sewing a couple of layers of UL mesh to some Argon fabric and using that as an inner tent, mesh to the inside. // the aluminium coated foam building blanket would work but definitely not low bulk // as mentioned in that other thread simply using space-blankets is moderately effective and quite low in weight and bulk so perhaps layering UL mesh between two layers of RFL would work for you.

If low cost was a consideration using CostCo down throws might be worth consideration

[Pedestrian]

A few years back I was on a snow camping trip in the Sierra camped around 10k. We planned to build and sleep in snow caves but once we got to the spot, there was not enough snow to build caves – in my experience the best winter shelter.

I ended up just scraping up enough snow to build a low wall around my “camp spot” – very exposed in howling winds with temperature around 10 F (without wind chill). I slept in my 0 F synthetic bag in a bivy with all my clothes on and a jacket. I thought I might freeze to death overnight. To my great surprise I survived the night and was quite comfortable once I warmed up.

From that experience (and others) I would bet on insulation close to the body – warmer sleeping bag, bivy, extra clothing etc over insulation on the tent etc. Of course nothing beats the comfort of a snow caves if you have the time and snow to build one.

[Edward John M]

Having stayed in insulated tents myself the idea has merit

The longer the stay the greater the merit, lining the inside of canvas tents has a long history, it’s the application to UL that is interesting.

[Anonymous]

Hi Renee,

I don’t know how to compare down to Aerogel either way.  I don’t mind experimenting. I’m sure I’ll get some noticeable insulation out of it either way.

“Do you have reasons for ruling out more conventional insulation such as down or Apex? “

  I was originally considering Apex, and then thin foam, and was somewhat convinced out of these by others. That’s when I came up with the weight and bulk solving solution of Aerogel particles in silicone matrix, plus some air gaps and the IR reflector.

If you keep your vapor barrier inner, you don’t have to worry about condensation accumulating in your insulation”

.  That’s tricky. I’ve read some articles which indicated that materials can act odd the colder it gets, and that materials can become more permeable at sub 0*F temps.

You might consider a multi-wall tent (3 or 4 walls?) w/o any insulation but the air gaps.

Air gaps are not particularly efficient at thermal resistance, because of convection. I’d save some weight and especially some bulk, but with Aerogel, it’s a multiple factor of greater thermal resistance.

Or a baffled air gap as Thermarest uses in their NeoAir mattresses.  Any of these can be well under 4osy and compress fairly well.

The above definitely has potential, but I’m not sure how to replicate how it’s done in the NeoAir line. Also, they are as efficient as they are, because they are completely sealed up in combo with a loft anywhere from 2 to 3 inches for the higher R rated ones.  Either one of these would be hard to achieve on a tent, even if I could replicate the baffle system.

But it’s a generally good idea, and certainly the NeoAirs use it for good effect. Speaking hypothetically, one could create something like over sized NeoAirs with much lighter materials since they will not be subject to intense pressure, abrasion, etc and line a tent with these.  But currently that kind of project is above my engineering know how and capability most likely.
Maybe not though–it’s something to think about. But honestly, it’s just easier to throw some Aerogel particles in a silicone slurry and slap it on. I’m a bit lazy, and anything that can make something easier and more convenient appeals to me.  One of the reasons why I’m using the Membrane SilpolyPU4000 fabric is not just because of the light weight, but because of the PU coated side can be easily taped, which cuts down on sewing. See, laziness.  It becomes even more convenient because the other side is predominantly silicone, which works with the silicone/aerogel blend.

If the two coats of silicone + 1mm sized aerogel particles isn’t really enough, I could also coat the inner cuben as well. A 5mm layer of mostly Aerogel particles with silicone, along with 2 extra air gaps and an IR reflector is almost guaranteed to have some serious thermal resistance.  5mm is a common thickness for Aerogel particle infused fiber, insulatng blankets, and in those, there’s a lot more fiber than aerogel particles.

Thank you for the feedback

[Edward John M]

Do you mean 1nm sized aerogel? I was under the impression that powdered earogel particles were in the 100th of a millimetre size

[Anonymous]

Hi Edward,

Doing the mesh in between would provide a little more thermal resistance than just straight air gaps, but not a whole lot more. That space really needs lots of super small fibers or pores/cells to really still the air circulation. That’s why Down is so efficient, because it has so much surface area of something like fibers, within a given volume.

CCF’s can be significantly more efficient than Down per volume, but Aerogels are even significantly more efficient than CCF.

If I get the kilogram of Aerogel particles for 60 dollars from China, it’s really not that expensive. Though ordering direct from China is always a bit of a gamble.  I’ve done it a few times though and have been mostly satisfied.

Thank you Edward for the collective brainstorming

[Anonymous]

I wish we got enough snow around here for snow caves!  We do occasionally, but it doesn’t tend to last long.  The temps seem to fluctuate above and below freezing quite a lot in this area.

Yes, as mentioned, have already fully recognized and pointed out and agreed that insulation directly near you is far more efficient. Addressed that question/issue and explained why I’m willing to sacrifice some weight, bulk, and money for a greater environmental thermal efficiency.

[Anonymous]

Do you mean 1nm sized aerogel? I was under the impression that powdered earogel particles were in the 100th of a millimetre size

In this case, I do mean mm, see below:
http://www.buyaerogel.com/product/lumira-aerogel-particles/

You can also get them much finer than that for coatings for more smooth paint or the like.  However, the larger the particles, the more thermal resistance efficiency you get. It’s somewhat akin to the concept of loft in conventional insulation, but at a reduced scale. The thicker the aerogel particles, the more thermally resistant because the more surface area and more air that is stilled.

That’s why the silicone will have to be more thick than usual, to help protect the particles, which are brittle.

 

 

[Anonymous]

And the company from China that I’m looking at, says their particles range from .3 to 5mm in size (5 seems a little too big for this use).

[Edward John M]

Wasn’t there a company doing baffled double layered blow up aluminium coated survival suits a while back?

Now something like that should work

[R]

You should double check my math, but I think the data on the IC3120 Aerogel listing means a 5mm layer of particles (no silicone binder added) would weigh ~20osy and have an R value of 4. MatWeb says adhesive grade silicone is almost 10x as dense.

 

 

[Edward John M]

osy Ounces /yard2 ?

OK that is heavy compared to APEX or down but the R-Value per mm is impressive

 

[R]

Yup.  Ounces per Square Yard.

And yes.  Aerogels are known for being incredible insulators, but not, apparently, light insulators.

[Anonymous]

You know those iconic blue discs of aerogel, that are super light and super insulating?  These particles are made out of that silica based aergoel. Some have a hydrophobic treatment though, because the silica based aerogel breaks down in water.

The density of the actual silica material itself is somewhat heavy (lot of mass), but the particles and monolithic structures made out of same only contain a very little actual amount of silica per a given volume, the rest is 98.9% very stilled air.

If these structures are almost 99% air, I’m not sure how it could weigh so much per such a small volume?

It’s possible that the ones with a hydrophobic treatment or coating (?) weigh more since there is so much surface area within even a small particle, and presumably the surfaces of same all get covered with this treatment or coating?  But even then, it’s still primarily air.

Aerogel blankets on the other hand tend to weight a lot, because they use very dense fiber batts, that are bonded with aerogel. It’s not the aerogel particles which are making them heavy, but the very dense fiber batts plus bonding agents (I guess they do that to protect the particles better?).

I could be wrong about the above. I’m not an engineer type.

[Anonymous]

    Never mind about the price I quoted earlier for the China stuff. Apparently there was a translation miscommunication earlier on.  I originally asked about the price of 5 kg of it, and she said it would cost 300 dollars.  So I assumed it was 60 dollars per kg at these small volume/weight orders.

She recently wrote back clarifying that she meant it cost 300 dollars per kg (quite a difference!), plus 80 dollars shipping.

Not near as affordable since none of these Chinese companies sells less than a kg at a time.

I’ll have to go with the US based company that sells 950 ml for 55. I’ll order 1 first, and if I need more, will order more.  If I had the money, it would be much more cost efficient to get the kilogram since the volume for same should be rather large.

[R]

At $95 for .95L, a 5mm thick layer will cost $241 per square yard.  Adding silicone sealant will reduce this somewhat, but you’ll still be in the same ballpark.  They offer an 8mm blanket for ~$400/yd2 that’s about half the density and thermal performance of the powder.

I calculate the surface area of the MLD Solo Mid at 6.8 sq.yd. so you’re looking at $1600 for 5mm of powder (4R) or $2700 for the blanket (3R).  You could line your tent with NeoAirs and get the same weight and warmth as the blanket for 1/3 the price.  Packed volume would probably be similar.  The powder would probably be bulkier as a deflated NeoAir is <5mm thick.

 

 

[Author]

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