More sleeping bag modification

[Moondog55]

I bought a BA Farrington a short while ago with the intention of cutting it short and using it as a half bag in my day pack.
But after playing with it for a while I changed my mid. I've taken the side zipper out and sewn up the side and I have added a substantial centre wedge. 200mm at the top, widening to 300mm about 200mm down and then tapering to a point.
Girth is now a reasonable 180cm
A LW summer overbag to add about 7 to 10 degrees to whatever is inside [ in this case a S2S Spark0 with a 10C/15C rating] total weigh 765 grams in the stuff sack
I used a scrap of old nylon taffeta and some of the 42GSM Thinsulate as the insulation.
I can wear a LW warm top inside to get the torso insulation I need because the S2S bag is so skinny I can't do the zip up and I may on-sell it after the next walk

[andrewa]

I think it’s time you just bought 5-6 m of the exceptional sleeping bag fabric Monkey Puzzle fella sells, spend a few weeks dreaming up your ultimate design sleeping bag, and making it, rather than modifying other stuff (!) - I did this when I worked at MDs 40yrs ago - a differentially cut bag with chest baffles and a “seamless” goretex shell, 900g 550 loft fill - wonderful intellectual time working out the issues of how to put it together as I went off to sleep at night, esp getting the differentially cut bits to meet at each end - 1.8kg - great project but not used for years)……as I now love a quilt….just made a new one with MP fabric - shell weighs 160ish grams, 400g of ~600loft down and I reckon I’d be fine in the snow here if I wear down jacket and pants, as I normally do.

A

[Moondog55]

The fabric has arrived and I'll be doing it but as a synthetic overbag/ or overquilt. I do like tinkering and this was a project for a specific purpose.
However I think that the UL fabric is still much more difficult to sew

[Moondog55]

You're right of course Andrew. I just costed my desired ultimate bag at the PHD site and the price is high.
Naturally I can't afford $3000- for something I probably will never get to use. An extra thousand plus dollars to get a centre zip in a wide fitting isn't a realistic purchase at my age and fitness/health levels
That doesn't stop me from dreaming tho
I am surprised that you used 600FP down tho, I would have thought that the cost benefit ratio of using 900FP would be greater when labour is one of the biggest cost savings to DIY

[andrewa]

Hi Ted,

I have not been convinced that the extra loft/weight savings from these “high loft” downs actually translates into anything useful!

Reduction in shell weight does, which is why I use a quilt.

Presuming I used 900 loft down instead of 400g of ~600 loft done, logic concludes that I would be able to use 270g of 900 loft down to get the same fill as 400g of 600 loft….yep, a weight savings of 130g, but at way more cost, and there are many other ways to save 130g from your pack - eg make your own pack and save 1-1.5kg!

It’s about the overall performance of all your gear really.

Andrew A

[Moondog55]

Having owned a sleeping bag using 1000FP down myself I have to disagree on that point Andrew but using the lightest shell fabric that does the job is surely a given

[andrewa]

I concede. I’ve never played with anything greater than 750 loft, and that was many years ago.

But I look at the weight of all the stuff I’m taking to NZ tomorrow, and realise that an extra 100g of down is diminutive….a pair of socks is 100g…..yes, counts the cents and the dollars follow.

A. Happy dreaming about the project!