Which bag do I use?

[Moondog55]

I need a deep winter system for a forthcoming trip and I am buying an outer bag to use with my existing sleeping bag

However I have two very similar sleeping bags, both are the same design and expedition cut; bags are my 2 J&H Ultras; one has 900FP down and the other has 650FP down

There is a 200 gram difference between the bags; one is 1050 grams using the 900FP the other using the 650FP is 1210

Both bags are the same age and about the same usage and have suffered about the same 10% loss of loft. I am taking one in to have it cleaned and topped up with an additional 100Grams of down this W/E

Intuition is telling me to get the bag with the lower FP down topped up with some new stuff and use that as the inner but I am having second thoughts

Is my intuition wrong?

[Zapruda]

Why is your intuition telling you to top up the lower FP bag? down durability? cost?

I would top up the 900fp bag because of the weight savings and added warmth. But I'm a weight weenie, so...

[Moondog55]

Because of the compression issues suffered by inner bags being squashed by the outer bag I'll be using 900FP down in the outer bag for sure.
When talking about a sleep system weighing over 7 kilos a few hundred grams don't really mean much

[Moondog55]

Anybody willing to take a WAG here??
Even One Planet have very little idea and they make double bags as a matter of course for Antarctica

[Moondog55]

Headed into the city this AM to check out the oversized OP Cocoon to see how it goes layered
I really am not comfortable using a side zipped bag but the difference in cost may be the deal maker, unless I can persuade OP to start making a real cold weather SB that is, one with a properly placed minimum zip

[Moondog55]

One Planet shop visit was very productive in a couple of ways
it turned out that using the inner bag with the lowest FP down gave the best final result and despite my dislike of side zips I am going to go with a large Cocoon with Expansion Wedge; unless of course OP do bring out a big winter bag with a centrally placed zip that is.
Combined free loft is over 320mm, 160mm of insulation, clothing could add another 40mm to that easily

[stry]

Too easy

I am always surprised by the references to 650/700 fp for early OP bags (although I am sure that they are correct).

I have, and have had, various claimed to be 850 bags, and although they are better, they don't seem to me to have 20/25% more loft than my old Winterlite. Also if early OP are 650, the cheapo, and some not so cheapo, bags must be 500 or much less.

I am not surprised that that your somewhat intuitive idea to use the lower FP Ultra as the inner proved correct.

I wouldn't sweat the zip. I believe that a side zip can be better, as the down filled sausage over the zip doesn't drop away, and the potentially heat losing zip is not on top where convection, combined with the sausage hanging away from the zip can increase heat loss. I should mention that I turn inside the bag, not with the bag - unless the hood is pulled up snug.

[Moondog55]

You may be correct, the inner bag will probably rotate inside the outer, I'll try hard to keep my exhaled breath on the outside even if I have to wear a snorkel mask.
What did impress me was that cheap reflective SOL liner stopping the inner bags down from being compressed by point pressure from elbows and hands when I was trying to see how well I fitted. I think that will turn out to be a major advantage to its use as a liner and may well be worth the 200 grams it weighs

[Moondog55]

I just got my Ultra back after the top-up
100grams of 745FP DWR duck down and the new weight is 1180 grams. It seems that it had lost over 120 grams of the original fill and that my scales are only moderately accurate
Interestingly I have a condition report that came with the bag after the work and it says that the remaining down was in excellent condition.
As soon as I can afford it I am going to have the other Ultra topped up with the best down they have because the difference with this bag is amazing

[stry]

That's good news. Another example of how long lived a good down bag can be if it is looked after.

The fragility of down seems to be greatly over estimated nowadays.

[FNM]

@moondog55 Hi mate. Where does one go for a top-up/repair? Cheers

[Moondog55]

@moondog55 Hi mate. Where does one go for a top-up/repair? Cheers

OP will do any OP or J&H bag as a courtesy for $44- if it needs cleaning plus the cost of the down
It is actually a pretty easy job DIY if you are careful but here in Victoria most people use Remote
http://remoterepairs.com.au/
There are other places too
I've done it myself on other sleeping bags, I used a standard sewing machine and a lot of pins

[FNM]

Thanks Moondog.

Another q re bags and their weight. On the MDs website it shows the Bag weight for the Travelite 500 as 1.2kg, and the fill weight as 520g .. Does that mean the total weight is 1.72kg or is the fill weight part of that 1.2kg bag weight? .. I'm thinking the latter, but just to be sure.

[Moondog55]

520 grams of down and the rest is the weight of the shell; so 1200g in total.
Personally I try not to buy a sleeping bag the shell weight of which exceeds the fill weight but the Travellite series are OK as traveling bags More so at the current sale price, all things being equal tho if they have a 700 I would get that in preference and an XL if they still do the Large size.