DIY half bag

[undercling-mike]

Yeah, you'd want to flare it out to be as wide as possible in the upper section for the shoulders. With the half bag as it currently is do you put the jacket inside the bag or over the top?

You might need 2m of insulation to do it, I'm not sure 1.5m will be enough, even with using the offcuts from the lower section. You might just get away with 2m of fabric with using the offcuts to extend the top inside layer.

[Moondog55]

It fits over my LW jacket but not over any of my big ones, but all the big ones open from the bottom as well so no problem also no problem if I flare it
Simon has no more of the 2.5 left as i purchased the last meter but I think I bought 1.5 meters last purchase so I may have enough, if not just keeping the wind off would be a help

[Moondog55]

When using multiple layers of synthetic insulation is a layer of scrim between each needed?
If it is what is normally used if the non-woven polypro isn't available?

[simonm]

When using multiple layers of synthetic insulation is a layer of scrim between each needed?
If it is what is normally used if the non-woven polypro isn't available?

Climashield is usually just layered on top of each other.

[Moondog55]

OK Works for me then
I do remember Quallofill needed scrim between layers

[Moondog55]

Yep, it should still work nicely. Another option that just came to mind would be extending the synthetic layer above the top of the existing bag to make a kind of hybrid FF vireo. Probably need another ~40cm to go above the shoulders.

Interestingly I just checked out PHD via my email update and they are using exactly this idea but with shell fabric only and no insulation

[Moondog55]

When using multiple layers of synthetic insulation is a layer of scrim between each needed?
If it is what is normally used if the non-woven polypro isn't available?

Climashield is usually just layered on top of each other.

Hi Simon
Climasheild comes in an orientation along the length of the roll; is there any advantage by laying alternate layers in different directions?

[simonm]

When using multiple layers of synthetic insulation is a layer of scrim between each needed?
If it is what is normally used if the non-woven polypro isn't available?

Climashield is usually just layered on top of each other.

Hi Simon
Climasheild comes in an orientation along the length of the roll; is there any advantage by laying alternate layers in different directions?

That is a very good question. I don't think it would be noticeable if there was a difference.

[Moondog55]

Good questions deserve expert answers. I'll leave that in your capable hands for now then

[simonm]

Good questions deserve expert answers. I'll leave that in your capable hands for now then

Thanks.

[Moondog55]

Just cut out the foot circle
One layer of 2.5 looked thin so I used 2 but I won't do that on the body [ maybe a small extra bit over the feel"??] the thinner ball point needles are making a difference with this LW Argon fabric but I still don't like sewing it

[simonm]

I would use a sharp (microtex) needle rather than ball point for the Argon.

[Moondog55]

I tried that and these work better for some reason, I also changed to the Rasant thread for these jobs
These are the finest needles I've ever used and about $1.50 each although I'm sure I could have paid less

[simonm]

I tried that and these work better for some reason, I also changed to the Rasant thread for these jobs
These are the finest needles I've ever used and about $1.50 each although I'm sure I could have paid less

Ok - well whatever works is good. I use the Rasant120 for the Argon with a size 80 needle though could go to 70.

[Moondog55]

Yeah 70's Size #9
But I usually use #16' #18' and occasionally #21 for real heavy pack canvas
Anything smaller than a #12 Is very fine when I'm sewing

[simonm]

That is a big change from normal. Once you get used to it, the lighter fabrics are pretty easy to work with.

[Moondog55]

That is a big change from normal. Once you get used to it, the lighter fabrics are pretty easy to work with.

I hope so; so far I'm having a lot of trouble getting it to stay still on the work top, every time the breeze blows through the window it seems to jump up and move

[simonm]

That is a big change from normal. Once you get used to it, the lighter fabrics are pretty easy to work with.

I hope so; so far I'm having a lot of trouble getting it to stay still on the work top, every time the breeze blows through the window it seems to jump up and move

Yes, no breezes help.

[undercling-mike]

I'm looking forward to seeing how this turns out, what design did you decide to go with? The lightweight fabrics don't have much dimensional stability which can make them tricky to handle when sewing. FWIW use a size 70 universal (ballpoint) needle with Rasant 120 thread and haven't had any problems but it depends a lot on your machine.

[Moondog55]

I've cut a circle about 30mm larger than the foot of the half bag and used a double layer of the insulation there.
I'm using 2 layers of fabric just on the foot
The inner layer of fabric is from a PIF of the inner from a macpac tent and is even lighter that the Argon; it's only there to contain the stuffing so doesn't need to be windproof
The rest of it I am going to make as long as I can using what fabric I have, but only insulating to the top of the down bag unless I find another scrap of Argon to do better; but as wide as the fabric is and tapered down to the foot
Having a windproof layer over the torso will add substantially to warmth; would go over the down jacket but fit inside the storm parka
I should have ordered more fabric so I could use synthetic all the way up to the chest; but I didn't think it through fully
Cecile asked me to weigh the foot part for fun and with the pins in it masses 27 grams.
There were a few tiny scraps left after cutting the insulation into the circle so I just added them between the 2 layers

[Moondog55]

This UL fabric and insulation takes some getting used to
Part of me thinks canvas is easier, a lot easier
I'm glad this is a relatively cheap project because it isn't up to the standard I expect of myself
The slightest lapse of concentration and I have 5 or more layers of fabric sewn together without even noticing
It's like trying to sew air

[Moondog55]

Is it possible to use painters masking tape rather than tearaway tissue paper or scraps of fabric when doing the joins?
I have lots of masking tape here

[Moondog55]

Finished but I am too ashamed of my work to post photos
I can tell you all tho that the hybrid is incredible warm
Total weight of the hybrid bag is 525 grams in the new larger stuff sack and initial impressions are it is about 3 times as warm and at least twice as warm as the old Thinsulate bag plus 1/2 sack combo and compresses better
I have been a fan of hybrid bags since Scotland but only now are the synthetics becoming light enough to take real advantage
While working on the modification I've been thinking
If you used LW argon for the liner shell you could use stitched through construction using No-See-Um mesh cut as a spacefiller [ + 10 to 15%] to constrain the down and cut the outer as a differential shell [ the same way we are thinking of making the vest for The Boss] and trap a lot of air for not much extra weight
Simon if you were bringing in the 3.6 ounce Apex I would recommend that, the 2.5 may be a little light for winter and two layers is probably to much for the half bag concept
A combination of 3.6 + 2.5 would work well for a winter bag too
I can now lend the Thinsulate bag to the friend whose down bag is probably a little too lightly insulated for the snow

[simonm]

Hey mate - yes I am looking at 3.6 as well, and may get this in the next shipment. Due to the bulk of Climashield, freight from the USA is pretty hideous, which is why I have gone with the lighter 2.5oz. Hopefully though I will be purchasing direct from Climashield in the not too distant future, freight is still a killer but due to the sheer size of the minimum order requirements it will be more economical.

Well done on the project regardless of the aesthetics.

[Moondog55]

I understand that if you buy in big enough bulk you can get it vacuum packed and therefore reduce that bulk by 90%
The weight of the bag plus Tyvek cover plus stuff sack is now 685 grams, that's half the weight and this feels as if it will be adequately warm. First frosty nites and I'll know
Have you considered pre-selling at a discount to get you money up front to enable that direct purchase?

[undercling-mike]

Moondog, sounds like it was a success even if it doesn't look too pretty. I'd also be quite keen to see pictures, even from far away to see how it turned out.

Not sure what you were asking with your question about masking tape, do you mean as an alternative to pinning? I've never used masking tape or tissue paper.

[simonm]

I understand that if you buy in big enough bulk you can get it vacuum packed and therefore reduce that bulk by 90%

I already get it vacuum packed.

[Moondog55]

Mike it was in regard to using paper over the synthetic insulation so it don't get caught in the works
I tried it, sticky isn't the problem [ green tape] it is simply too strong and won't tear along the stitch line Newspaper or greaseproof kitchen paper both work and the newspaper is cheaper and weaker
OK pix follow

[Moondog55]

OK here's the pictures

[undercling-mike]

Looks like it turned out well and should function nicely for your intended purpose despite any sewing problems you had along the way.

If you had the chance to start from scratch and design something to fill the same need how would you design it or what would you make different?