Jan 31, 2012 at 10:22 am #1284958
I'm purchasing material in the next couple of days for a duo-mid(ish) shelter. the layout is simple enough, but that's true of most myog projects. What always gets me are the small details. Like for instance, how to form the "peak" of the mid. I've got the zipper and a piece of fabric that terminates the zipper coming up the front of the tent, which meets the flat felled seam coming up the back of the tent. I've been putting my origami skills (which I don't have) to work cutting out and folding paper mock ups but it always comes out looking kludged up.
I'm hoping to get it figured out on paper, then do a small scale trial in some scrap fabric. With my specific kind of ocd, I know that if mess the execution on the actual tent enough, I'll be unsatisfied and bothered every time I use it.
And, do you need a reinforcement patch on the peak of a small two person mid?
BTW, here's what I have in mind- cutting the fabric like this eliminates about 36% of the lenght of seams I'd need to sew. The downside, is I can't do any cat cuts w/o seams at every corner of the mid. I think I can manage that with some side panel tie outs in a shelter this small.
the patterns lay out on a 62" wide sheet of fabric like this –
it uses almost exactly 7yds of fabric (like 2" shy) but I'd get 8yards to be safe and to have some left for some other small projects.
I toyed around in my head about the idea of sewing on a net skirt, but after reading some of the pros and cons, I think if I feel I need it, I'll just make an inner net tent to go with it.
BMJan 31, 2012 at 10:44 am #1832235
Jim W.BPL Member
Fabric stretches differently in the lengthwise (warp), crosswise (weft) and diagonal directions. Your "oragami" design might suffer from having the fabric oriented differently on different sides. Also I think the typical ridgeline seams on a pyramid help to stiffen those features- but I'm guessing.Jan 31, 2012 at 10:46 am #1832238
brent driggersBPL Member
@cadyakLocale: southwest georgia
Nice design!Jan 31, 2012 at 11:07 am #1832245
Yeah, I've thought about that. The idea to cut the fabric this way came from lookign at Zpacks hexamid. I noticed he startes out kind alike that, folding the fabric around, and adding on some panels to make it the right size. But, he's using cuben that doesn't stretch. But I've also seen larger tipi shelters that have the fabric cut like this.
You can see the seams on the hexamid here – http://zpacks.com/large_image.shtml?shelter/hexamid_plus/hexamid_plus_blue_angle_l.jpg
The seek outside tipi's look to have their fabric wrap around in a conical shave as opposed to a bunch of triangular cut pieces of fabric with nothing but vertical seams. I couldn't find any good pics though.
Actually, what has me most concerned with this design (have never pitched a 'mid before) is the hexagonal shape. The footprint is slightly wider in the middle than the ends, just for some extra space, vestibule area, if you will, and more cushion from wind deflection pushing the sides down on top of me while I'm in it. I'm worried that will make it harder to pitch nice and taut, as opposed to a straight rectangle shape. I guess I'll find out soon enough (I hope)…
BMJan 31, 2012 at 11:35 am #1832254
Jim W.BPL Member
I have a three-sided 'mid that pitches perfectly every time- flat ground, bumpy ground, it doesn't care. Just like a three-legged stool can't wobble. I think you could do the same with a hex- here's my idea:
Figure out the "perfect" setup. Then tie light cord between every other corner stake loop- so you have a triangle of cord inside the shelter. Stake those three corners out first, nice and tight. Put up the pole, then stake out the other three corners. That's how I set up my triangular tent- corners first, pole up, then midpoints to make it slightly hexagonal.Jan 31, 2012 at 12:43 pm #1832288
That's a brilliant idea. I'll definitely have to try that. I imagine after the shelter is up, you remove the cord? If it were pitched close to the ground I would think you could leave it, but if it was pitched off the ground for ventilation then it might be a bit in the way.
But I think I have the peak detail figured out.
the yellow bit would be some fabric sewn to the end of the zipper, pretending the zipper ended at that black line. Everything folds up neatly. I just need to take extra care to make sure the panels are lined up properly for the point of the cone to come out nice and symmetrical. I'm trying to save money, but I'm thinking I'll need to budget in a few sheets of thin Masonite to make a template for laying out the sides…unless I can find something else cheaper from which to make a semi rigid template.
(edit: pics weren't rotated properly)Jan 31, 2012 at 2:42 pm #1832365
Maybe my MYOG Duomid thread can help a bit.
Concerning the peak, you will want a reinforcement patch of something at least 4 oz/yd. I put triangles of reinforcement on each of my 4 pieces (piece A,B,C,D) that touch the peak before sewing it all together. I didn't do it, but if I could again I would sew 2 pairs of the panels together to form piece AB and piece CD which would then be sewn together. There is a lot of seam bunching at the peak of my MYOG Duomid since I didn't do it this way. I bet some could be avoided by doing this.
As far as zipper termination goes, adding a vent over the zipper entry solves this problem quite nicely while providing a little extra rain protection for your stuff while entering the tent. It would require you alter your pattern significantly though. You can check my thread for an explanation of how to make a vent.
After using my Duomid a bit, cat curves for a more taught pitch would be nice, but aren't necessary. Tieouts do just fine and can provide a bit more headroom. Good luck. Post pictures when its complete!
Edit: One way to avoid needing a string system to setup your mid would be to make it rectangle shaped but a little longer. Normally you set up a mid by staking you 4 corners with a little slack and then erecting the pole. To make it hex shaped, give the long sides extra slack and stake out the midpoint. The midpoints are a little higher off the ground than the corners. This give a little more ventilation and you can be less precise with setup. Just an idea. Good luck!Jan 31, 2012 at 3:47 pm #1832397
Thanks- that is very helpful. Especially the thoughts on how to assemble it with the reinforcement in place.
I have some Dyneema X Gridstop left over from another project (bike frame bag) that I could use for the peak reinforcement. I like your idea of how to attach it. 4oz fabric would make it pretty stiff in that area, I would imagine…
How I intent to assembly my tent is to sew the green and the tan pieces together first, making the really wide isosceles triangle, then sewing that to the teal and brown pieces, respectively, to make each "half" of the mid. Then join the back panel togehter with a flat felled seam, and finally the front with the zipper. Add tie outs and so on from there.
I opted to go w/o a vent. There was a thread a while back about 'mids and they were going back and forth over the benefits of the vent, and the general consensus as I recall was that it didn't help with condensation very much. And also, I live in the desert southwest where I'll be spending most of my time outdoors, so humidity isn't a problem.
What did you use for those little ties to hold the doors open? And also, how is it buckling the little side release buckle on the bottom of the door from the inside of the tent with it on the outside? If at all possible, could you post close up pics of your side panel tie out reinforcements? And are you happy with their location? Would you place them somewhere different if you were to do it all over again?
BMJan 31, 2012 at 10:28 pm #1832603
Paul McLaughlinBPL Member
You may have issues with fabric stretch on the bias at your corners. What may happen is that the fabric stretches so much more on the bias ( which your ridgelines to the corner will be) that the centers of the sides will be well up off the ground before the corners come taut. If you don't mind them being up in the air, and you have enough range of adjustability with your pole to handle the stretch, then it may be okay, but it also may be a challenge to keep it taut thoughout the night if the fabric continues to stretch, as you not only have to keep jacking the pole up, but also loosening the guylines at the midpoints. I had one of the early chouinard megamids back in the early 80's, made from a light PU coated nylon which had too much stretch on the bias, and it had this problem – when the pole was maxed out the thing would keep stretching and so you couldn't get it tight, and if you jacked up the pole with a rock or something the mid-points of the sides were like a foot off the ground. They replaced it under warranty with one made from a heavier (1.9 oz) coated nylon, which they switched to, as mine was obviously not the only one with issues.
I'd go with a cutting layout that uses a little more fabric but keeps the stretch more equal on the lines of stress.
As for the heaxagonal shape and setting it up. I have an MSR twin peak which has a fairly similar floor plan ( thought it has two poles instead of one), and I'v e found it pretty easy to set up – I treat it as a rectangle at first, pgetting one end staked down and then the other, not too tight lengthwise, then the poles go in, then I do the mid-side stakes, pullng it tight, then I go back in and jack the poles up a bit (I'm using adjustable ski poles since this is my backcountry ski shelter) to get it nice and tight. Pretty easy, there's nevre any worries about how far out the middle points go, it's sort of automatic.Feb 1, 2012 at 9:44 am #1832752
I had to read that twice to try to understand what you are saying, but I think I get it now. It's 60" wide on the ends. I've contemplated adding another line lock in the middle of that panel, and maybe that would help. It's easy or me to get carried away and want to add a million tie outs around the whole thing.
David- I have a couple more questions regarding the construction… I noticed you have a baffled zipper on your tent. Is that necessary or is a waterproof zipper good enough? Is it only baffled onthe outside or is there another flap on the inside? And is a #3 zipper good enough or should I get a #5?
Sorry for all the questions… I'll try to research some of the answers on my own- but it's nice to get first hand information form someone with first hand experience.
BMFeb 2, 2012 at 12:55 am #1833193
Ivo VanmontfortBPL Member
My manner to forming the peak(copy of a trailstar):
Before I made the last seam to close the shelter, I laminated the insite with a second layer of silnylon.
After closing the shelter, I reinforced the in- and outsite of the top with a circle of silnylon which was folded into a cone and again laminated with silicone.
Strong but (to)heavy
Van pyreneeen 2011selektieFeb 2, 2012 at 9:01 am #1833305
Maybe it's heavy but it looks very clean and well executed. I have the same idea, to lay the tent flat before sewing the last seam, and sewing the reinforcement patch on most of the way, leaving a portion un-done where it will overlap, and sew that after the last seam of the tent is sewn.
I also plan to laminate the tie out reinforcements this time. Did you just silicone it on with straight silicone spread thin or did you dilute the silicone some with some mineral spirits?
BMFeb 6, 2012 at 4:02 pm #1835439
For the door ties I made a loop with string on either side of the seam. I added another loop made of shockcord with a cordlock on it as a 'stopper'. I can remove it if they don't get much use. Its a little sloppy, but I don't know where to get proper 'stoppers'. I suppose a plastic button could work.
The buckle on the outside in no problem since you are supposed to keep it buckled as you zip and unzip the door.
My tieout patches are just a square of scrap 1.9 nylon with a bit of grossgrain sewn to it to attach some stout shockcord. Fold the edges under and sew to hide the raw edge. Then I just sewed it the panel. I didn't think too much of where I put them on the panels so the ones on the door and back are lower than the ones on the side. Oops. 2' off the ground looks to be about where MLD puts theirs, so I'm sure that is ideal.
I used a #5 zipper since MLD did. Others have reported that a #3 is fine for tents. With all the warnings on MLD's website about buckling the buckle before using the zipper I assume the zipper takes a lot of stress so I opted not to go lighter. I used only an outside rain flap. It should be fine. Any water that may get through should roll down the wall since it's steep. I suppose a WP zipper could work. I didn't think of using one. Maybe its worth a shot.Feb 7, 2012 at 9:22 am #1835743
Thanks- that's really helpful. My fabric arrived yesterday so now I guess I need to figure out how to lay out and cut my fabric. I need a cheap way of making a template, I think. If it gets too complicated, it'll end up cheaper to have bought a duomid! Of course it wouldn't then have any of my custom additions though…
I bought the waterproof zipper, but I think a normal zipper and a storm flap would be much cheaper. That uretek #5 zipper is a bit spendy. I bought it from Quest because the same zipper for OWF is quite a bit more money… My only deal now is I don't think I bought enough 1/2" grosgrain. I bought a bunch of line locks and D rings as well as some mitten hooks for clothesline hooks, or to hold up a future inner net tent. I'm trying to think this one through and make it as nice as possible.
Anyway, thanks again…
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