(summer down bag) + (summer Apex bag) = cold-ish weather goodness?

I have had the exact same thought to do that with my 30 degree bag. My concern in that the down might get compressed by the syn quilt on the top. I don't know if that's a legit concern or not. I hope to hear from others who've tried it. Or I will just buy a pretty new cold weather quilt.

When layering bags, watch out and make sure that the bags don't compress each other from tightness. You might have to crawl in one of them, and then layer the other one over your bag like a quilt.

When I first started winter camping, I used to layer a old marmot mistral (kind of like the cat's meow) over a summerlite (32 F) down bag. The Marmot was rated to 25 F when new, but was about 15 years old and had lost much of it's loft by this time.

I took this system down to -10 F, so I suspect that what you are describing would work fine in your climate. Only way to know is to try (in a safe-ish environment with extra clothes as backup). I ultimately switched to a designated winter system because the double bag system was pretty cramped.

Good point on the compression, guys. Another good reason to get the MLD Spirit in a wider size.

Thanks for the info Ike! Like your Mistral, my old Cat's Meow 3D has lost a lot of its loft. I figured it would be a reasonably safe bet that a top-notch quilt like the MLD Spirit, even the lightest one, would add 10 to 15 degF to my WM down bag.

id expect that at least …

i think its a safe bet

remember to size the quilt to fit over the bag

Remember that the covering fabric weighs something

If you have one bag, you have two layers of covering fabric – top and bottom

If you layer two bags, you have 4 layers. The extra 2 layers weigh something

Say, your bag has an area of 3 square yards. If you're using "heavy" 1.1 oz fabric it will add 6.6 ounces to have an extra layer of quilt/bag. If you're using "light" M50 0.75 oz fabric it will add 4.5 ounces.

Better to just get a bag or quilt that's rated for your minimum temperature.

If you're buying a new bag/quilt, it isn't that much more expensive to get one with a little more insulation.

Of course, if you're using equipment you already have, it would be very expensive to buy a new, additional, more insulative bag/quilt.

Why don't you look into Hammockgear.com. Their 20 degree quilt is $229 and weighs 21 oz. The MLD Spirit quilt is $195 (I think). So for about $35 more, you could have a quilt that should get you down to the 20 degree area. You can also add more down for pretty cheap.

+1
They make quality quilts using 900 fill. They are also very nice people to work with.

Hammock gear quilts have an option for a snaps or sewn footbox. Do the snaps not let drafts in? I looked at the pictures and it seems like you would loose heat where the cinch hole is on the foot.

Also the overfill – did someone mention each 1oz lowers the temp by around 5F?

There is one very good reason to use a synth overquilt/bag instead of down

Dew point and condensation ….

>>>Also the overfill – did someone mention each 1oz lowers the temp by around 5F?<<<

I did (on another thread), and it varies. That is a very "general" statement, and should only be taken so far.

As you overfill (stuff, cram in) down, it compresses. There is a point of diminishing returns here, as you can add so much down to a given amount of space that eventually it will loose the ability to insulate effectively.

When looking at the Hammock Gear products (purely as an example), they have 3 main top quilt products. A 40°, 20° and 0°. Each has different sized baffles capeable of holding an appropriate amount of down. Add an ounce of overstuff, and you get about 5° improvement in insulation comfort. Add 2 oz and you get an other 5°. Add 3 and you get 5° more. Add a 4th oz in the same space and it doesn't help, because it is so stuffed that it needs a bigger baffle to be effective again.

It is not an exact science (depends upon the baffle size, shape, down rating and quality, etc). Hope that helps and does not confuse. This is a very brief summary of what has been discussed at hammockforums.net in the past 2 months or so.

Yes that makes perfect sense. Thanks for the info.

The best way to layer for more than one night is with your synthetic bag on top where it, not you down bag, will accumulate the body moisture that condenses in the cold top layer and shell.