DIY half bag

[Moondog55]

Just in case Mike decides he doesn't want to make it for me.
There is a technique for stitched thru construction that uses a short line of stitching thru both layers but no in straight lines right across the width of the shell. It was used by Egge of Switzerland a lot if anybody can remember that old high-end brand.
Egge used it because it gave the greatest loft per gram of down before going to a fully baffled or double shelled construction.
Can anybody advise me on stitch spacing and stitch length and what this type of sewing is called??
My Google-Fu can't even find pictures of Egge gear to show what I mean

[stry]

Pretty sure I understand what you have described, but I have never seen it. Sounds like a pretty clever idea.

I had a couple of Egge vests (may still have one, if it hasn't been given away) but they were conventionally stitched through.

I think you could look at a few bits and pieces and pretty safely make an educated guess as to what you want. Can't see it not working.

[Moondog55]

I have a good picture in my head of the Eskimo bag I first saw this stitching being used on, but as I had the Eskimo Expedition at the time I never paid enough attention to fix the dimension and spacing in my head
I'd like peoples ideas here on how much down I really need, as all I want is a 10C boost to what I normally carry.
I suggested to Mike that 90 grams would be enough; actually it would be a little less as Simon sells by the Imperial ounce 28.?? grams and the next step up is obviously 4 ounces.
My Tamarack has 8 ounces and that is superwarm as a booster but too big for what i want to carry in my daypack.

[andrewa]

Why not just sew in baffles? It's easy, and still only 1 row of stitching on each bit of fabric.

Those bags dated from the 70's, didn't they, when shells were often made of cotton, and we didn't even rate down by loft. In those days the weight saving by not using baffles was prob pretty significant.

I remember in the mid 80s making a differentially cut winter bag with 2 ply goretex outer, and the shell weighed about 1kg!. Now, with these ultralight fabrics and baffle material, and high lofting down, a shell can be about 3-350g, or less for a quilt. Maybe the designs of the 70's are now less appropriate ( I certainly no longer "over design" my sleeping bags and quilts as I did back in the 80s). Just an idea!!

A

[Moondog55]

Obviously you've never seen one Andrew. They were state of the art even by todays standards.
Some of the lightest nylon shell fabric anywhere and down that would be the equal of todays 850 stuff easily.
It was Richard Egge who started using very fine mesh for baffles, until then makers used the same nylon used in the shell fabric. Perhaps I am old fashioned but for winter bags I really do prefer either no zip at all or the short centre zip. Eskimo bags were a short centre zip and a shaped hood. All cut to wear a down suit or pants and jacket/half bag inside them
The sewn through Eskimo bag wasn't sold as a summer bag, it was a specific bag cut to fit inside another walled Eskimo bag as a double when not wearing the suit but could be used a warm weather bag. My ex-wife lost my Eskimo half bag years ago by lending to somebody to use for a kids camp and it was never returned.
Yes I could use baffles but if sewing this myself I'll probably need it to be super simple and I thought this was simply the simplest way

[simonm]

I suggested to Mike that 90 grams would be enough; actually it would be a little less as Simon sells by the Imperial ounce 28.?? grams and the next step up is obviously 4 ounces.

It says 28 but I go usually closer to 30grams.

[Mark F]

I believe the current iteration of the Egge sewn through system is called "karo step" quilting in which only short sections of baffling are sewn into the quilt arranged in various patterns. While down can move around it is still sufficiently controlled to minimise the creation of cold patches.

[andrewa]

I stand corrected! No, I haven't seen one. I have a vague recollection of the brand, but by the time I got into bushwalking in my late teens in the late 70's, Fairydown and Mountain Mule were the "up there" brands.

However, getting back to baffles, I reckon it'd be easier to sew them in than to fluff around with karo step quilting ( which I have never done, but I've sewn lots of baffles).

A

[Moondog55]

Well you are one up on me. I've never sewn one
Thanx Mark Now I can google that.

[Moondog55]

OK Googled Karo step quilting and they are not the same unless what I read was wrong or I read what I was reading wrongly.
Does a Karo step involve a short piece of net baffle material sewn between the two layers?
Or '
Is it a stitch through in an open box pattern?
I just read lots of pages and it appears as if there is a web of LW baffle material between the two shell layers and all of the others seem to have much more stitching than I remember

[simonm]

Does a Karo step involve a short piece of net baffle material sewn between the two layers?

Yes.

[beean]

I don't see why you couldn't do Karo step quilting without the baffle material. It'd still allow for down movement.

Perhaps to offset the cold spots you could make the inner shell bigger than the outer and overstuff. But it might just be easier to baffle

[andrewa]

The whole concept of sewing in little pieces of baffle material at 90 degree angles would do my head in, not so much sewing them onto the first bit of fabric, but having to sew them in similar places on the other bit of fabric.

I did read an interesting post on a hammock forum about someone who had made a karo step underquilt from Cuben fiber, but used double sided tape to hold the baffles in place - mind you, you could do this with normal baffles too.

A

[stry]

Like beean said - it doesn't have to be baffled. (And I also agree that it would be a nightmare trying to DIY it with baffles)

The benefit over conventional stitched through is obviously the reduced total length of stitch lines. So any appreciable reduction in that length should be effective. I think the benefit of the technique would be greater with stitched through than with baffled construction.

Just look at the spacing on an existing bag, pick a few numbers, dummy it up on the floor and use your judgement. You might like to start by thinking about half stitch/half gap ? FWIW, I would offset the gaps in the lines of interrupted stitching, which should reduce down movement.

[Moondog55]

I think the hard part is determining what the minimum number of stitch points for each weight of down. That is the hard part.
I cannot see the point is adding short baffles for something this LW.

EDIT
If I do wind up making this myself or if I make one myself as a personal instructional would a drawstring foot be just as warm and effective as a fitted foot box?
Just been thinking about the old Kimptons Arctic I used to own and how handy the drawstring was. Anybody here remember that old Super warm bag?
Water resistant tightly woven japara inner and outer with a full 3 pounds of "Superdown" and vertical baffles but a stitched thru cowl hood
Kimptons offered that bag with 2, 3 or 4 pounds of Superdown

[simonm]

I found a link to a Karo under quilt Evan did -

Karo Step Underquilt Tutorial.pdf

(571.12 KiB) Downloaded 1002 times

I am considering it for my next top quilt build.

Like others have said I guess there is no reason you couldn't do it without the baffles.

Edit: Here is a link to a sewn through Karo baffle quilt - http://www.backpackinglight.com/cgi-bin ... d_id=51009

[simonm]

Edit: Deleted due to information already contained in above links.

[Mark F]

Personally I think the karo step is rather fiddly to build and you need to be pretty sure the layout will provide sufficient down control. My own leanings are towards the baffle pattern used by EE. With quilts that end up a little under filled due to dampness etc control of down at the edges of the quilt becomes quite important and the EE design handles that rather well.

[Moondog55]

What works for quilts my not work for a half bag tho
There is no edge

[Moondog55]

I've been doing some quick figuring here and I think I must have something wrong
I just calculated that I can get this half bag from only 2 linear meters of LW Argon fabric with some scraps left over.
Does that sound right?
Just had a visual flashback to the Egge bag stitching as well Looked like this >-< and about a hands breadth long in total so ~110/120mm

[Moondog55]

Mike is going to make it for me as there is no way I can do this myself while we are renovating. I'm hoping he does a Show&Tell of the progress but if not I'll post the finished product.

[Moondog55]

I can however make a down vest as I have the room to do that and I can use the scrap of nylon taffeta I have.
How many grams/ounces of down do I need for an XL vest?
Making my own means I can make it pullover style which I really do prefer
New thread coming soon then

[DanShell]

I can however make a down vest as I have the room to do that and I can use the scrap of nylon taffeta I have.
How many grams/ounces of down do I need for an XL vest?
Making my own means I can make it pullover style which I really do prefer
New thread coming soon then

I used 3 ounces in mine.

viewtopic.php?f=53&t=17937

[Moondog55]

I remember that thread
Well Simon has 3 ounces of down with my name on it so maybe a hooded vest is the way to go

viewtopic.php?f=53&t=19465

[perfectlydark]

Would love to see the vest, sounds like a good project!

[Moondog55]

Underclingmike has finished my half-bag and will be sending it soon, I'll let him comment on the build. But with 130 grams of down and a finished weight of 265 grams it should give me the boost I need to feel safe in a winter bivvy.
I haven't started the vest project yet fr two reasons. The money to pay for the fabric and down and the need to find my vest pattern in the renovation mess

I'll give a review and critique as soon as i have used it, maybe the glamping W/E
but the PHD bag in the link was my base point

http://www.phdesigns.co.uk/alpine-ultra ... -delephant

[undercling-mike]

Yep Moondog's new half bag is in the post and I'm keen to hear his thoughts on it. The bag is made with Argon 90 inside and out and sewn through construction. Finished length is 130cm, this comes up to just about my chest and I'm 178cm tall. Top girth is ~135cm and foot girth is ~95cm. The bag just has a simple drawstring at the top, which exits on the side (either side since the bag is symmetric). Without further ado some pictures:

HalfBag3.JPG (90.82 KiB) Viewed 36603 times

HalfBag4.JPG (64.39 KiB) Viewed 36603 times

HalfBag5.JPG (69.55 KiB) Viewed 36603 times

The bag fits quite easily into the stuff sack and could be compressed down to around half the volume but it's probably better not to compress the down too hard in the long run.

The bag is constructed of two panels (front and back but they are symmetric) for each of the inner liner and outer shell, these pieces were sewn together and then the shell and inner were aligned and the sewn through baffles were done. The sides are sealed with a rolled hem and then the hems on each side were sewn together to form a tube. Finally the foot end piece was sewn in.

I've just got a couple more pictures showing how the fabric was put together:

HalfBag1.JPG (83.94 KiB) Viewed 36603 times

HalfBag2.JPG (86.13 KiB) Viewed 36603 times

The bag is not a straight taper, the top and bottom thirds have a shallow taper with more taper in the middle third.

Overall I'm quite happy with how this turned out and it should make a nice booster bag combined with a jacket or even on it's own with an insulated jacket in summer.

[Moondog55]

Nice pictures and I'm waiting with bated breath as they say. That looks like a full 30mm of averaged insulation there too which is plenty for my needs
Given the Easter break I'll probably receive it Tuesday or Wednesday
I've never understood why these have gone out of fashion or use

[FootTrack]

Another seriously nice/cool piece of kit Mike. Great colours too! Well done.

[simonm]

Lovely work Mike and congratulations Moondog.