How hard is it to make a pyramid shelter?

[Jennifer Mitol]

So…since I’m not allowed to buy anything ever again, I’m going to try my hand at making a shelter out of silnylon (or ???)

I really like pyramids, and the hexamid-type shelters (Zpacks hexamid, deschutes, etc)

Eventually I’d like to try to make a pyramid with built in netting/floor ala solplex/altaplex from Zpacks – sort of a frankenshelter child of Zpacks and MLD.

I’m not too bad at the sewing machine – it’s the drawing it up that I’m seriously struggling with.

Does anyone have any recommendations for readings/websites with some ideas about how to start my design?

Thanks in advance!

 

[Roger Caffin]

Hi Jennifer

Getting sucked into the MYOG world is dangerous. (But fun.) Welcome.

The problem as i see it is that you will still have to buy materials – lots of different materials. And Tools, and finishings, and …

Me, i would stick to silnylon. It works very well, is much less expensive than Cuben, and is much easier to work with. Just check the hydrostatic head (HH): over 1,500 mm is preferred.

We expect lots of photos in due course.

Cheers

 

[Jerry Adams]

my article from 2010, pretty much still valid, square but you could use it to make other sizes:

https://backpackinglight.com/myog_silnylon_floorless_2-person_tent/

This might be useful

http://backpackinglight.com/forums/topic/52485/

or:

http://trailsandtracks.blogspot.com/2011/07/myog-pyramid-tent.html

or:

http://chrisroane.blogspot.com/2011/02/myog-10×10-pyramid.html

I don’t know I’d do it to save money because you get sucked into making another version

If you want to do a hexagon rather than square, not too difficult to calculate length of sides – a^2 + b^2 = c^2 – a and b are sides of a right triangle and c is the diagonal side.

suluk46.com used to have a Cuben description but it seems to be gone now

[Jennifer Mitol]

yeah, unfortunately I already, secretly, fell down the MYOG rabbit hole a while ago.  I made a nice summer blanket for myself (it was supposed to be a quilt, but by the time I stopped making mistakes at the foot end it was pretty much too short to actually have a footbox of any kind.

This seemed like it would be RELATIVELY easy, easier than my still-unfinished pack project I have in all sorts of pieces on my sewing table.  And I keep thinking about combining what I like about the Zpacks enclosed tents and the space of the MLD duomid.  Oh, how to blend the two…….

And yea, I realize this will save me no money whatsoever.  It’s just a line I keep using over and over and over again.  Makes it seem like I’m committed or something.

[George F]

I am supposed to be working right now so I will keep it brief: get SketchUp. Once you get the hang of it you can try out all sorts of variations and spin them around see how they look. More on my various blunders and the lessons learned later.

[d k]

Hi, Jen –

I used Google Sketch-Up (which I learned by doing this tent) to design a tent that had some features I liked from the Zpacks Duplex (general structure) and some from the SMD Haven (non-centered peak, top vents), and some ideas of my own (floorless, netting panels with no zippers).  I also took measurements from a Haven inner that I had in my possession.  Then I just went at it.  It wasn’t perfect, but it works (at least on one trip, but then I hurt my back so it’s been sitting around since last June neglected and untested any further).  I used silnylon because it was cheap and I had a bunch (long ago Walmart had lots for $1/yd).  Maybe someday I’ll make one from cuben if this one proves to be good in weather.

Here’s my post on it: https://backpackinglight.com/forums/topic/104473/

Jerry’s plans for a ‘mid shelter are a good place to start, or if you have something in hand you want to copy you could do that.  I would encourage you to go for it!  It gave me months of obsessing pleasure in the planning stages, and only a little frustration when it came time to put it together.  Cheap silnylon or silpoly might be a good place to start rather than making mistakes on cuben.

Debbie

 

[Jennifer Mitol]

oh yeah – i’m not going to try cuben any time soon!  my design skills are less than, um, acceptable, so i need about the cheapest fabric I can reasonably use to play around with.  Thankfully some VERY nice BPLers sent me quite a bit of sil a while ago that I’ve been using for various stuff sacks and rain kilts and things.

I just want to work on the design at the moment…i’ll try sketch up to see how that works.

thanks guys!

[Ben Wortman]

Jennifer

If you end up getting the Sketchup program, I have a pile of shelters designed all in one file.  They range from all sorts of Mids to tents.  Nothing really ground breaking, but the drawing part is done.  If you or anyone else wants the file i can email it to you, just send me a PM.  You can copy the shelters out and modify them you your specific requirements.  Then add measurements to make your patters.

Mids, especially ones with all sides equal are fairly easy.  The trickiest parts for me is always how I am going to finish the peaks where the poles go.  If you get that far, there are plenty of good advise on the forum.

https://backpackinglight.com/forums/topic/101895/

http://backpackinglight.com/forums/topic/61825/

http://backpackinglight.com/forums/topic/97776/

Good luck.

Ben

[Hiking Malto]

I must be one of the few that finds cuben easier to work with than other materials.  just to add to the help, I developed a spreadsheet that allows you to input critical dimensions in excel and it determines the length of all sides of the flat panels.  It was used to make my version of MLD meets zpacks but I used an inner bug net instead of integrating it into the mid. (Allows flexibility to use with bivy in non-bug season without the screen) I could probably hunt it down, Pm me your email and I can send it to you.

[Bill Giles]

You might want to consider using SilPoly rather than SilNylon. It isn’t necessarily any easier to sew, but it doesn’t absorb water like nylon and may be more UV resistant. The cost is in the same ballpark as SilNylon and SilPoly is available from Ripstop by the Roll. I’ve used Silpoly to make a couple of tarps.

[James Marco]

Jennifer, I used to be a carpenter. As such, I usually figure any angles with a board and a rafter framing square. Basically, it is possible to calculate all this but the formula is not worth calculating if you have a square with a full set of tables. Lacking a square with a full set of tables, you can use something like this: http://planetcalc.com/1147/  (Very simple to use.)
Anyway, for a typical  pyramid, the hip calculations are:
10ftx10ft@45 degrees:
Wall length length: 7.07ft
Corner/Hip length: 8.66ft
Total height at center: 5.00ft

9ftx9ft@45degrees:
Wall length length: 6.3640ft
Corner/Hip length: 7.7942ft
Total height at center: 4.5000ft

For 8.5ftx8.5ft @ 45degrees it is:
Wall length length: 6.01ft
Corner/Hip length: 7.36ft
Total height at center: 4.25ft

The odd lengths do not well correspond to the width of a 5ft wide piece of silnylon (or other materials) though. This is usually OK, since the peak actually needs extra stitching for some sort of pole pocket and vent openings/rain shield needed.

http://www.1728.org/volpyrmd.htm allows you to calculate multiple sides, 5, 6 or 8 is common. But, this is a bit harder to use. You can figure it out, I think.

Other Notes:
For “half” “Mids” such as the Z-Packs, you undoubtedly want beaks. These are actually just segments of the original calculations.  The closer the tent skin is to your face, the more it will condense water. If your feet touch the tent, they WILL get wet. Generally, 16″ is about the minimum clearance wanted. I like 24″. The more shallow angles require longer “running lengths” but can make the thing a little lower in the center. 45degrees is a good compromise angle for clearance and width. I believe Z-Packs uses about 46-48″ as a center height. For me, this is awkward. My staff only measures 43-44″ and is a fixed length. Measure your staff to prevent fiddling with it. Typically a “Mid” will require more height than a single staff will provide.     Just some random thoughts…

[Jennifer Mitol]

this is all great stuff guys…thanks!

[monkey]

Here’s one more link to a similar project: http://backpackinglight.com/forums/topic/55205/

Out of interest what made you think to go MYOG route, have you changed your mind about red Duomid?

[Jennifer Mitol]

nope – i got the red duomid….and it’s really nice!  I really like the color.

But here in Texas there is almost no public land, so that means no easy weekend backpacking trips for me anymore.  All I can do is plan some nice big ones each year (which is still great!), but I don’t get to indulge my backpacking jones 2-3x/month anymore.  So I want something other than buying gear to keep me knee deep in my gear nerdi-ness.

 

 

[Nick Smolinske]

I’ll second the recommendation for silpoly over silnylon.  For a mid I’d go with the 20d silpoly and not the membrane sil.

The silpoly is a bit easier to sew and has low stretch and low water absorption.  It’s really nice not having to adjust guylines after it rains.

Silnylon is harder to sew, but more forgiving once sewn, because of that stretch.  So it’s easier to make a mid that pitches tight with nylon than with poly.  That said I think the poly is worth it.

[James Marco]

Yup, MYOG can be interesting and still benefit you. Silnylon can be had relatively cheaply at OWFinc.com. They have seconds of various colors, though it can be limited in the larger quantities. At $4.61/yd this is about the cheapest for many tarps, cloths, and other projects, since the bears don’t really care about what it looks like.

Jerry also published an article at BPL. He goes into a lot of detail about building mids and fabric layout. https://backpackinglight.com/myog_silnylon_floorless_2-person_tent/ is a good place to start! I had almost forgotten that Jerry’s article had a good fabric layout example in it. I would note that you can cut this stuff together, my wife calls it “stack cutting.” Simply rough out 4 rectangles then pin them together. Then cut all 8 pieces at once…MUCH easier.

[Jennifer Mitol]

Thanks Nick, I was going to ask about silpoly.  I’m intrigued by it, but looking at ripstopbytheroll I wasn’t sure which strength I should go for.  What about the PU4000 coating???  worth it/not worth it?

And why not the membrane silpoly?  (or as my autocorrect keeps telling me: SILLY)

[Nick Smolinske]

Jennifer,

You can make a good mid with the membrane but I just worry too much about it’s durability in strong winds.  I sold my first prototype membrane mid and the customer reported some wind damage.  It’s possible that it just needed reinforcement patches, but I’ll see what it looks like when it comes back.  Should be a few days.  In any case I made him one out of the 1.4 oz PU4000 silpoly with better reinforcements.

I also made one out of the 1.25oz silpoly, and it’s held up well so far.  I haven’t had it in any really driving rain to tell whether the coating is worth it, but it held up to some very strong winds.  I’ve used my old silnylon tent in some pretty intense rain and it misted a little but still kept me dry.  So I’d guess that the difference between the 1.25oz and the 1.4oz w/PU4000 will be whether or not you tolerate the fabric misting through in heavy rain.

[Jerry Adams]

is that the 0.9 oz sil poly that failed?  That would be interesting to know how it failed.  Would it be possible to reinforce it better to avoid?

[Nick Smolinske]

I’ll know more when it gets here in the mail in a couple of days.  My guess is that if you are careful with it and put in big reinforcement patches that it won’t fail.  They did say that it had some ripping near the apex, which surprises me.  It might need a larger reinforcement patch up there.  This was the 1.05oz finished weight version.

[Jerry Adams]

with 1.1 oz silnylon (1.4 oz finished weight) you don’t really need any reinforcing, in my experience

except at the peak.  Make a 6 inch circle of the 1.1 oz silnylon and put it over the top and then sew it around the perimeter to the main fabric.  Sewing it to the flat felled seams of the main fabric provides a lot of strength

maybe need a 12 inch circle of the lighter weight silpoly, and then a 6 inch circle on top of that, and glue them with silicone:mineral spirits, along with sewing.

[Jennifer Mitol]

Jerry – just had a really thorough read of your article and all the comments after.

So…cat curves, eh?  Necessary?  Difficult?  If I wanted to change the pyramid to be more of a rectangle instead of a square would that change the curve???

[Jerry Adams]

I don’t think it matters if it’s a rectangle or square.  Each ridge should have a cat curve with the same deflection.  maybe 1 or 2 inches.  I don’t know if poly, since it doesn’t stretch so much, should have more or less.  If you’re very precise in layout and cutting, then you probably don’t need as much deflection.  Mark a line on both pieces of fabric, where you want the row of stitches to go, and then as you sew along, make sure you’re going through the middle of the line on both pieces.

Make sure and take two long strips and practice.  Put marks at both end that line up perfectly.  Then sew them together and you’ll find the marks no longer line up when you’re done with the seam – the piece against the foot slips a little relative to the bottom piece.  If you practice a couple times you can get them to stay aligned.  If they slip, when you step up the tent, it won’t look right – there’ll be wrinkles or whatever

[George F]

When I made my shelter I started with straight edges but found it was too floppy along the ridge line and two of the corners. I just flipped the shelter inside out, marked and sewed a curve where I wanted to tighten it up, trimmed and sewed it flat. Probably cheating, but it worked for me. I even did it twice on the ridge line before I got the curve I was looking for.

[Jerry Adams]

I’ve used that technique also.  I’ve also strung a string between points, against a piece of cardboard, with the string deflecting a couple inches, and then marked on the cardboard where the string was.

I think it comes out better if you use Roger’s spreadsheet and measure.

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