Integrated under quilt, experience in welding fabrics?

[KangHang]

Hi,

I´m new to the forum, but have been studying quite a bit. My plan is to make a very light setup, with invaluable inspiration from multiple threads and posts on: integrated UQ, strecthside, detachable UL bugnet, parallelogram hammock (dropped for now), various footbox designs, hardware-free sls, pentagon dyneema tarp (asymmetrical on one side), catenary cuts, etc. etc. Too many to thank, you all know who you are, much appreciated!

i´m looking to make an ultralight single layer hammock in 1.0 hexon, experimenting with a body-mapped, integrated UQ in apex and 7den fabric. To avoid weakening the hammock body fabric, i would like to avoid sewing (except for hem and possibly channel), but instead weld/bond/tape the UQ directly to the hammock. Would this be possible? I´m thinking heat welding wouldn't be too good, as it would also slightly melt the hexon (?), potentially weakening it. The welding in itself would never be under much load, as it should only be able to hold the apex. - Does anyone know which tape/adhesive i should use? -I´m thinking it should stretch a little, allowing for the 1.0 fabric to move and stretch as it would without the tape. Some kind of 3M-like double sided tape, adhesive or? As far as i know this hasn't been tried before (?), but any experience with welding ripstop would be much appreciated!, Thx a million times.

There is still some planning to do, but will post as i get going.

Best

[leiavoia]

Most fabric tapes and glues are for temporary usage (while you're sewing it together, not for permanent bonding). They easily come apart with some tugging. Not a long term solution.

You can actually heat-weld some synthetic fabrics, but i dont have much experience with those. Search youtube. Likely you need specialized tools.

However, there are many good arguments for maintaining the UQ separate: washing, lack of adjustment options, swap-outs if damaged or unwanted, changing for different trips or weather or different hammock altogether. Single layer 1.0 hammocks are not robust and likely have a limited durability. If you bundle that with the UQ, you lose both if either fail.

I use either a stretch-fabric or clew suspension on my quilts and tie on with a light cord (from the quilt ends out to the hammock ends). Its very simple and avoids permanent attachments.

[brianb]

I've enjoyed leiavoia's posts, lots of good info.

For me, I've used an integrated underquilt for 3+ years. Double layer hammock and 3/4 length sewn on UQ good to 45ish degrees Fahrenheit. If you're going to build your own I'd recommend a double layer. Seems like any welding you might try would damage the integrity of the fabric, so a single layer may fail on you. In mine the main layer doesn't get any sewing so no compromise in strength so you can use one of the UL fabrics. Also I think you'd be surprised how much stress you put on a hammock when you lay in it. I tried a single layer hammock with integrated UQ and it did rip from the sewing.

I like the flexibility of a double layer hammock. On mine with the integrated UQ, when it gets below my UQs temps I can supplement by either using a second UQ, a pad between the layers, a UQ protector, or some combination of those. Advantages and disadvantages with each and with all MYOG you have to do your own testing to know its limits. I've miscalculated more than once, but the double layer is forgiving and I've been able to make up the difference by putting a rain jacket or some other impromptu insulation between the layers to supplement. Double layer makes insulating your foot box super easy also. I carry fairly light, so this works for me. Good luck.

[WV]

KangHang,
I've long been a proponent of insulated hammocks, but leivoia's reasons for preferring separate underquilts are very compelling - especially the ability to wash just the hammock, not the insulation. I keep making hammocks, always trying out new ideas, so I can afford to specialize. Most of the time I sleep in a hammock, so that one gets a separate underquilt which doesn't need to be washed as often as the hammock. When experimenting on insulated hammocks I'll use strong fabric, then perhaps refine the idea in a lightweight version for backpacking. The people who designed the first solar powered airplane kept making each component lighter and lighter until it broke. Then they backed up one step. I'm trying to do the same thing with my hammocks, but without the breaking part. It involves some guesswork. An early down insulated winter hammock had baffles sewn to the hammock body, and it worked because the hammock fabric was Supplex nylon. I noticed after several years of use that the polyester thread holding the longitudinal baffles to the Supplex had broken in quite a few spots. The down didn't seem to have migrated much, so I assume the places where the thread still held worked like karo step baffles. Looking at any quilt or insulated hammock with baffles, you'll see that the thickness of the insulating layer varies quite a bit. The baffles establish a consistent minimum thickness at the seam lines and the rest puffs out. That's why I'm interested in your plan to "body-map" the attached underquilt. I've found that greatly increases the insulating efficiency by keeping the thickness more uniform. I make my maps of the hammock shape using triangles. Jeremy at Bonefire Hammocks showed me an insulated hammock that also had a very accurate fit. I believe he based his map on grid measurements. There are two other things I've tried to get the right shape of the insulating layer. One is using transverse baffles spaced fairly close together. Instead of sewing the top of each baffle to the hammock bed, I sew a channel and run a 1/16" bungee through it, sewing the ends to the hammock at the edges. This pulls the top edge of the baffle up against the hammock body, and it also allows flexing (something that welding would inhibit). The second thing is using a mix of down and synthetic insulation. The down is for the middle of the hammock, and a 6" strip of less compressible synthetic insulation is quilted to the bottom layer along the edges where shoulders and knees might press outward and make thin spots in the insulation. If the body-map is accurate and the right size, the down will expand and fill the space most uniformly underneath you. I have used this plan, even without baffles for the down, though I throw in a couple of extra ounces of down for insurance. My current lightweight backpacking hammock uses all of these factors (including baffles with elastic tops). It is the equivalent of a hammock and a 30° F. underquilt, and it weighs about 2.25 lbs.
Making it was a lot of work. I suggest you concentrate on your body-map to create panels for your bottom layer, but forget the baffles for now. I found if I multiplied the measurements for each triangle by 1.3 to 1.5 (depending on how thick I wanted the insulation layer to be) it came out big enough. There's a second way of using down + synthetic: quilt synthetic insulation to the fabric entire panels before sewing them together. Then sew the bottom layer to the hammock and toss in 3 or 4 ounces of down on top of the synthetic insulation. A first prototype could be made with just synthetic insulation - saves money.
Incidentally, I've used these insulation schemes on regular gathered end hammocks, lightweight gathered end adjustable hammocks (replacing diagonally opposite corners of the fabric with whoopie sling clews), regular bridge hammocks, and Peoples' Bridge Hammocks. The bridge hammocks are easier to map because they are symetrical.

....
Or do something entirely different, and tell us about it.
David

[KangHang]

Thx for many good thoughts. My idea is to make it with climashield, but perhaps throw in some down to fill any potential space between the CS and the hammock fabric. Good thoughts on body mapping WV! I guess my primary concern at the moment is to find a solution to attaching the underquilt to a single layer hammock. That would shed weight by removing a layer of thermally inefficient fabric (as compared to similar weight insulation) and attachment cord for a regular underquilt. The trick, as I see it, is how to do it without weakening the fabric so as to be able to go with 1.0 hexon or similar weight fabric. As you write Leiavoia, apparently adhesives in general don’t stick very well to nylon, as it does with cuben for instance, but I will try and ask around. -The adhesive wouldn't have to hold much weight, so strength is not so much a concern as longetivity.

I fly fish on the coasts of Denmark while wading for long stretches with a backpack, including food, sleeping system, stove etc.. For it to be comfortable enough for casting and carrying at the same time, the system needs to be very light. Thus, for me to change to hammocking, I will need something close to the lightest tents (altaplex or similar) or bivy systems, and something that sets up very fast.

Hope some adhesive oracle drops by, thx everyone!

[HangingOut]

Single layer 1.0 hammocks are not robust and likely have a limited durability. If you bundle that with the UQ, you lose both if either fail.

I have been using a WBBB 1.1 for almost 10 years and it hasn't failed yet. I liked it so much that I talked Brandon into making me a custom XLC with a sewn on tip cover all made out of 1.1. That is now my go to hammock and it only weighs 17 oz. I think the durability is a function of how much the occupant weighs.