Synthetic quilt principles

[James R T]

Hi folks, first post

I’m interested in making a synthetic quilt (down won’t work for my work situation), for work. I’m planning to use Climashield Apex. Presently, my sleep setup is usually:

1. a sleeping bag (used as a quilt), which I’m trying to replace
2. a liner (I don’t like wearing base layers to sleep)
3. base layer top if I have to
4. and one Therm-a-Rest ridgerest (though I plan to make a serious upgrade to the x-therm).
5. Season-appropriate tent
6. I tend to sleep pretty warm

I have a few goals for the quilt:

1. Weight–as light as I can, of course
2. Warmth–I’d like to be warm down to 20-25 F with the sleep system, so that I can stretch down a few more degrees by layering up.
3. Easy construction

I don’t care about compressibility too much. I have big packs, but I’m good about not filling them (I don’t like stressing my gear by compressing it to the max… er… min)

My main questions:

1. What weight of apex should I use?
2. What fabric should I use for the outer layer?
3. Regarding outer fabric, is there an effect on breathability for calendered vs. uncalendered?
4. Regarding outer fabric, is there an effect on warmth for calendared vs. uncalendered?

Thank you for any advice!

[Jerry Adams]

how to make synthetic quilt down to 20 F? – use down : )

I have a down quilt that’s good to maybe 30 F if I’m wearing some insulation inside.  2 inch loft, 4 oz/yd2.

You’d need 8 oz/yd2 Apex to provide the same warmth.

I made a 5 oz/yd2 Apex quilt but was cold below maybe 45 F.  I wanted something warmer so I switched to down.

So, for 20 F maybe 10 oz/yd2 Apex?

I’d use the lightest fabric.  I’ve used that 0.66 oz.yd2 nylon membrane.  That worked pretty good for down.  I made a synthetic vest with it.

The calendaring is where they run it over a heated roller so it sort of melts the surface a little.  Then it’s more down proof.  Fine for synthetic.  I don’t think it makes significant difference for breathability or warmth.

3 square yard quilt – 4 ounces for fabric both sides, 30 ounces for synthetic – 34 ounces total

If you make it out of down it will maybe be 5 ounces for fabric including baffles and 15 ounces for the down – 20 ounces total

[nunatak]

8 oz Apex. But if this is not available from the usual vendors you can layer 6 oz and 2.5.

[Mike M]

I have a 20 degree Apex quilt that uses 8 oz Apex and I think it’s underrated personally.  I also have a 28 degree Apex quilt that uses 6 oz Apex and think it’s underrated as well.

For me 6 oz is closer to 20 to degrees than 30 and 8 is closer to 10 degrees than 20- that’s with a high r value pad (Xtherm), appropriate base layers, wool socks and appropriate head gear/hood.  I also use wide widths to prevent any drafts.

YMMV :)

[Elliott Wolin]

Perhaps a radical suggestion:  you could make two quilts, one for around freezing and another lighter one to use in warmer temperatures AND over the first one (as an over-quilt) to bring its temperature rating down to 20 degF or whatever.  We do this (with 2-P quilts) and accept the few ounce weight penalty to save money and get more flexibility.

The penalty comes from the two extra layers of fabric when the lighter one is used together with the heavier one.  At under one ounce per sq. yd. it doesn’t add up to that much, as it’s only a few extra sq. yds.

[Jerry Adams]

a quilt uses maybe 3 square yards so an extra quilt uses 4 ounces, not that heavy if that works for you

Another thing would be to make a quilt using 8 ounces of Apex.  Use it and see what minimum temperature that’s good for.

Then, profiting from your experience, be prepared to make another one that’s warmer, or one that’s lighter for warmer weather

 

[r m]

I’m sure I’ve written this somewhere before…Anyway, worked for me and I was happy. Regarding two quilts:

I went with a down quilt (enigma pro 10F) with an apex quilt  (mld 38F spirit) over the top. Have been happy enough in tents around the -20F ballpark. I found the the down stayed nice and dry and the condensation off my body condensed and froze in the apex layer as days passed which took on a stiff and crunchy feeling.

Below freezing is interesting, it becomes a moisture management problem, something that can work for a night may not work for a week as the moisture builds up and things don’t quite dry out.

2 quilts gives me 3 options, so ends up being suitable for a wide temp range vs if I’d just bought one superwarm piece of gear suitable for -20F.

[Joost D]

Layering 2 quilts could be a good option.

For reference you could use this chart: https://support.enlightenedequipment.com/hc/en-us/articles/115002770588-How-to-layer-quilts-for-sub-zero-camping

But drafts could be a problem in such temp ratings. Maybe making the top quilt wider with draftstoppers? Or make the first quilt that you can close it up completely and then layer a wider quilt on top.

But I don’t have experience with freezing Temps. Just to about 30f with a 6oz quilt.

[Mike M]

On a recent snowshoeing trip I used a 30 degree down bag in conjunction with a 50 degree Apex quilt over the top- temps down into the low teens- I was snug as a bug w/ just a small weight penalty AND have two other warmer weather options.

 

[R]

Some theory on layering and temp ratings.

‘Room temperature’ is considered to be about 70F.  Most people don’t need any insulation beyond normal indoor clothing to be comfortably warm at this temperature.  This is the reference temperature that quilt and bag ratings are comparing to.  So a quilt rated for 50F provides 20F degrees of insulation relative to a reference of 70F (70 – 50 = 20).  If you put that much insulation on top of a quilt rated for 30F, 30 – 20 = 10, so you might reasonably expect the combo to be good down to 10F.

If you review the examples in this thread, you’ll find they pretty much agree with this.

[Mike M]

Here’s another data point.  Was out last weekend where the temps fell to -2F (was anticipating low temps of 10-15).  I had a 20 degree down bag and a 50 degree Apex quilt, I was fine until early morning (likely when it got close to/below zero) when it was a little uncomfortable- not terrible, but not comfortable.

 

[Edward John M]

Was that due to insufficient layering or not enough mattress?

[Mike M]

insulation layering- was a little shy, not much though- probably just the last hour or two where I noticed it

had a Large Xtherm over the top of 1/4″ ccf pad for pad

one thing that possibly could have contributed is the top of my quilt would slide off the bag- the quilt is a slick fabric as is the bag, I had the bag in the footbox of the quilt and it stayed put and then about half way up the quilt I used one of the quilt straps to go around the bag and it stayed put as well, but the top half would occasionally slide off

I think I have a fix for it though, Ron (MLD) is sending me an ~ 2′ elastic strap w/ a snap on each end that corresponds to the snaps on his quilts that seal around your neck

[Mike M]

another little tidbit- got the cord from Ron and it works perfectly- no more sliding off of the top portion of the top quilt

and one anecdotal note- this past weekend I checked a spot forecast for the area we would be traveling in- called for low temps in the lower 20’s, my buddy brought a legit 20 degree bag as did I; not one for fully trusting the forecasts I decided to throw in the 50 degree overquilt just in case.  Well it dropped down to about 10 degrees (possibly a little lower) the first night and he froze (said he almost got up and started a fire); me… cozy :)

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