New design of sleeping bag

widu13

Bushcrafter (boy, I've got a lot to say!)
Feb 9, 2008
2,334
19
Ubique Quo Fas Et Gloria Ducunt
Why does it need to be zipped at all? I realise your trying to cater for one size fits all thing but if I had a long jacket that came down to thigh height and a bag which came to around belly button height, there would be about 8 inch of overlap [on me] - would this not be enough coupled with an elastic or drawstring cord to close the jacket to the bag? - Bag on the outside, jacket in or the other way round?

I am interested to see where this goes......

Probably zip on the inside of the jacket; the reason for not having a parka is that a commercially made jacket will be used; so that apart from a zip there is no production cost for the jacket and as it will be aimed at a certain market, a parka style would not be well received and even impractical.
 

Johnnyboy1971

Bushcrafter (boy, I've got a lot to say!)
Dec 24, 2010
4,155
26
53
Yorkshire
But why not just make the bag a little longer and overlap the jacket. Surly the zip is going to be a weak spot that lets cold air through and will be fiddly to open and close if you need to get out in the middle of the night.
 

Tiley

Life Member
Oct 19, 2006
2,364
377
60
Gloucestershire
But why not just make the bag a little longer and overlap the jacket. Surly the zip is going to be a weak spot that lets cold air through and will be fiddly to open and close if you need to get out in the middle of the night.

If the overlap was big enough then, yes, it might well be better. The important bits - liver, kidneys and the other squishy bits - would probably be well served by an ordinary production jacket with a bag that came up to your armpits. You would then avoid the need for a zip system to hold them together, have a double layer of insulation around your midriff and avoid the expense and complication of having to create the sleeping bag hood. As I almost said before, that might (he said tentatively...) work quite well...
 

widu13

Bushcrafter (boy, I've got a lot to say!)
Feb 9, 2008
2,334
19
Ubique Quo Fas Et Gloria Ducunt
But why not just make the bag a little longer and overlap the jacket. Surly the zip is going to be a weak spot that lets cold air through and will be fiddly to open and close if you need to get out in the middle of the night.

It won't be an "edge to edge" join. Imagine a standard softie (by whichever manufacturer) with a zip set a few inches high on the inside. The baffle produced will be as substantial as a normal bag.

The whole point of the exercise is KISS, light and cheap. Start making a 3/4 length bag etc and that principle starts to be lost.
 

Johnnyboy1971

Bushcrafter (boy, I've got a lot to say!)
Dec 24, 2010
4,155
26
53
Yorkshire
An extra foot in length would be cheaper than fitting a zip and add next to no weight or bulk to the package but still allow you to use any jacket you want.
What your suggesting means you have to use a softie jacket or whichever you decide to go with.
Does this mean if i wanted to use my sasquatch coat i would have to have a zip fitted allowing me to use the system.
You say KISS, surly the easiest way would be to elasticate the top of the bag so it can be cinched around the body but overlapping the coat.
 

widu13

Bushcrafter (boy, I've got a lot to say!)
Feb 9, 2008
2,334
19
Ubique Quo Fas Et Gloria Ducunt
Yes, if you used any jacket other than the one finally chosen for the project you would have to get a zip fitted to use the bag; this system will only be marketed (at the start?) as a 2 piece affair. The sasquatch is a fantastic jacket but regarded by many as OTT in the UK!

I would sooner lie on a zip than having an elasticated cord around my middle. The main reason for the zip though is to minimise the bulk. The target users have limited space. An extra foot of even 6" of material is a fair bit of bulk, but I do take see your point.
 

widu13

Bushcrafter (boy, I've got a lot to say!)
Feb 9, 2008
2,334
19
Ubique Quo Fas Et Gloria Ducunt
The prototype came in this week. Bear in mind it IS a prototype. Immediately we picked up a few glaring omissions and a few items that we would like. However; this is a budget bag that will retail at £100. Bear in mind to add some things will mean quality, filling or other features would be lost.

The filling is a proprietary brand and the jacket will be produced by a known but not famous manufacturer (I'll divulge at retail time but don't bother asking until then, as I'll ignore it!) The bag at the moment accommodates a person of 6' 1" with a medium chest, but fits me (5'9") with a 47" chest so that I can turn the arms inside out and sleep with my arms inside. The size is an XL. This we have decided will NOT change. If you feel its too big for you...don't buy it!

IF the bag is successful it may be feasible to introduce other sizes. I had a quick compress and easily obtained a 20 x 20 cm ball, weighing 1600g. The manufacturer rates this filling to -5C. Don't forget, additional clothing other than undergarments, a bivvy bag, liner etc will add further insulation.

The jacket is long, coming below my crotch level. The bag is currently fastened directly to the bottom of the jacket, with the connecting zip being covered by only an unfilled flap of jacket material with no baffling either at the join or at the jacket zip along the body. The zips are standard jacket zips, some zips have pullers some don't. I think this was simply missed by the makers. It needs baffles.

There is no hood. We all agreed that a hood was important. It is likely due to cost that the hood will be a removeable "extra". The zips needed some care when doing up, we don't feel that this is practicable and are looking into the feasibility of burst open or YKK zips. We all felt that the jacket was 3" too long. The length would be taken from the jacket and added to the bag so the manufacturing cost is the same. I appreciate 'schrafters may want a longer jacket but they are not the primary target group.

The bag was simple enough to fit to the jacket either standing or lying. Strangely the bag IS baffled with a generous baffle of the same density as the filling. There is a separate 2 way zip on the bag and the bag has a fishtail foot with a reinforced foot box. We felt a waterproof (Paratex) exterior end/foot lining may beneficial but again this is subject to costings.

We all commented that to have the bag an additional 3" longer (to accommodate a person of 6' 4") may be a good idea. This obviously will add to manufacturing costs (material and filling)

Summary:

I think it is excellent quality, with a quality filling. Baffles required on front and joining zips, better (non snag zips) are needed.
The jacket length is to be shortened. Shorten jacket, lengthen bag.
Make the total overall length longer? Another 3”?
Zip pulls on all zips
Hood needed/to be available (Poss as an extra?)
Possible waterproof exterior foot liner. Paratex? (Probably prohibitively expensive)

Anyway, some money shots for you!

Full length image:


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Rear of zip join


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Fishtail


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Reinforced foot box


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Baffle


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Join


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Jacket


20121024_0841491_zpsc7dc6e1d.jpg
 

Retired Member southey

M.A.B (Mad About Bushcraft)
Jun 4, 2006
11,098
13
your house!
I may have missed this, it there an internal baffle at the join zip? Will there be a means of sealing the exterior baffle at the join, to function a a second join, so if the zip should be buggered I'm not then left with a jacket and a foot bag I can't join. I personally think there is to much fill lost around the joint so as to make a cold spot, would it not be possible to lift th zip up the outside of the jacket, it would give you a baffle at the joint too with no need to add one.
 

Retired Member southey

M.A.B (Mad About Bushcraft)
Jun 4, 2006
11,098
13
your house!
Hey that's like my idea! :p hahaha, the only thing wouldn't like is the zip inside, IMO sleeping on it directly would be uncomfy(even in kit) but that would need to be tried to prove or disprove. Looks good though chap.
 

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