Pyramid tent build

[Redback]

Now for the floor. Thanks to those in this forum for the advice and help.

[Mark F]

Great work. How about a few more details: weight etc
How much catenary did you put in the side seams?
What did you use to bond the reinforcement patches? ( I assume from the colour that you used an additional 1 or 2 layers of the main cuben)
What did you use to stiffen the vent edges?

[Redback]

Great work. How about a few more details: weight etc

The weight (before the floor) is 598g (including stuff sack, peg bag and 10xpegs). I used 0.8oz cuben. Adding in the extra features like the zipper clip, tie outs etc added up in the extra weight department.
The seams are first bonded with 1/2 inch tape. Then double stitched over the seam. On the outer layer is a 1 inch thick extra layer of cuben to seam seal the stiches.

How much catenary did you put in the side seams? They were 63mm deep at the widest point. I made a template out of ply wood using a spreadsheet, then traced them all out. Cuben has basically no stretch, so you certainly wouldn't need any more than that. 63mm over the course of 2.7m for that long side just gives it a gentle slope.
What did you use to bond the reinforcement patches? ( I assume from the colour that you used an additional 1 or 2 layers of the main cuben) The patches are made from hybrid cuben (also in orange, from Z-packs. They are taped and sewn onto the corners. Because of the force applied to them, they can slip (especially in warm weather) they need to be sewn as well. I made a full half circle for the reinforcement, and folded the rest in underneath.
What did you use to stiffen the vent edges? I used two methods for the vent. Whipper snipper cable and a plastic zipper tie. For the mesh underneath I used nanoseeum. It has a hybrid cuben framework around the vent as well for extra reinforcement.

I made a few weight sacrifices along the way. With the seams double taped and stitched I'm sure it will hold up well.

[north-north-west]

What did you use to stiffen the vent edges? I used two methods for the vent. Whipper snipper cable ...

I wish Hilleberg would do this on their vents instead of the mouldable wire. That cable is long-lasting and automatically springs into shape without you having to do anything, and I would have thought the weight would be pretty much the same.

Oh, it's a pretty good looking job, too. Well done.

[Orion]

Redback, that looks great.

The patches are made from hybrid cuben (also in orange, from Z-packs. They are taped and sewn onto the corners. Because of the force applied to them, they can slip (especially in warm weather) they need to be sewn as well.

How did you determine that they would slip without sewing?

[Redback]

I found out the hard way. Having the tent pitched drum tight. The patches moved up to about 10mm. Due to the nature of cuben I was able to peel the patches off, and restick them. Then I could sew them on again to prevent the slipping.

No harm done.

[Orion]

How long had it been since you applied the tape?

[Nuts]

That appears to have come up very nice Redback, well done.
The centre tie-out patches on mine crept a bit and I stitched them too. It wont matter a lot down so low but I wondered though whether this is the best way, given that any remaining stretch should only elongate the needle holes (which it did) and those patches seeped a bit.
Anyhow, looks like you have done an excellent job!

[Redback]

The tape had been on for about 10 days. The day it stretched was a 40 degree Melbourne day though.

[Mark F]

I'm wanting to understand a bit more about the creep of the reinforcement patches.

What tape did you use? If no specific model number then your source.

Did you tape the complete area of the patch or just the perimeter or some such?

Was the polyester fabric side of the hybrid cuben inside the join or the normal polyester film laminate? I gather that the hybrid has a polyester fabric - cuben fibres - polyester film layer. The reason for asking is that the 3M adhesive tapes often come in different thicknesses of adhesive to cater for different degrees of surface roughness.

Did you wipe down the fabric with isopropyl alcohol to clean the bonding surfaces before sticking it together?

Did you clamp the patches for a while after assembly?

Many thanks, I would like to minimise these sorts of issues before putting my tent together.

[Redback]

I taped the whole patch using 3M tape from Z packs. The patches are hybrid cuben - obviously I taped the cuben side of it. They were bonded for about 10 days before pitching.

The creep occurred (over 2 days) on a drum tight pitch on a balmy 43 degree Melbourne afternoon. The tent was set up for about 1 hour on each day.

[ULWalkingPhil]

Very nice, redback.

[davidf]

I have owned a BD megamid for years.

A mate made and handed over to me a small home made mid tent. It was his first go and its awesome. Made for use with a walkiking pole. About $60 in material from lincraft.light nylon, home proofed. If you have an iota on how to sew go for it and good luck.

[Redback]

That was my original plan, to use $5 a metre sil-nylon seconds.

In other news - floor is in and done. Will post a new photo soon. I went with Impetus 1.2

[Orion]

"go for it and good luck"

I spent considerably more than $60 on Cuben fabric so I'm going to be careful. I will be very disappointed if it doesn't pitch well, a result that I know is possible from the experience of a friend who had a failed attempt at copying a pyramid tent.

[Redback]

I'm interested to hear how you are going on your project Orion. I am far far from anything resembling an authority on the matter, but I'm happy to help if I can.

[Redback]

and I'm done!
Floor is now in - I used Impetus 1.2 The floor is connected to the main tent with nanoseeum mesh. This allows better ventillation while keeping insects out. I have also created a bathtub at the bottom so the walls sit up about 1 inch. Final weight (with pegs, peg bag and stuff sack) is 879g. It will fit 4 people tightly, and is a palace for 2.

Thank you kindly to everyone on this forum for their help, advice, and kind words.

[Orion]

Redback, your tent looks beautiful. Have you tried it out in the wild yet?

I'm interested to hear how you are going on your project Orion. I am far far from anything resembling an authority on the matter, but I'm happy to help if I can.

My project is sitting on the shelf awaiting me to become interested enough to spend the time to go to work on it. As our (USA) summer approaches I will become more interested.

I'm not sure how you can help me though. I thought (from reading BPL postings and my own limited experiments) that the tape was bomber. But you found there was very significant creep when under tension and at relatively high temperatures. I'm not using the hybrid fabric. And I will be using my shelter almost exclusively at 3000m and above, in the hours between late evening and early morning and when there is threat of precipitation (otherwise I'll just sleep out -- I intend to keep the floor/groundsheet as a separate item). Nonetheless your observation of creep concerns me.

The other issue is one of design. I have something well worked out on paper but I'm not sure how it will play out. This largely revolves around the curvature of the ridges. I could just give them a healthy curve much like my BD Megamid has, but I'd like to minimize them.

So... I'm not sure if you can help or not. Thanks for the offer in any case. Cheers!

[Mark F]

I suspect that the creep issue is why several manufacturers appear to sew then tape and sail-makers tape then sew. Order depends on whether waterproofness is important. Sewing get the panels in alignment and should remove any issues of creep. The tape removes issues of stitch hole extension under stress.

[Redback]

Thanks Orion, I have given it a 2 night field test doing the Southern Wilsons Prom circuit last weekend. Tent worked great - a little condensation on Night 1 but it just ran out and onto the ground. Night 2 had a slight breeze, no condensation at all. I'm pretty happy.

The creep I discovered was under extreme conditions. Using the tape and sew method I did, I have not seen any more evidence of creep.

[Orion]

I finally got around to making my cuben pyramid. It's more or less the same dimensions as the Duomid. It seems to have worked out; at least it looks okay in the garage.

I initially cut the panels without curve and taped them together with household transparent tape. The pitch was awful. I used clothespins on the ridgelines to improve the pitch but it still looked pretty nasty. I may have panicked a bit and overdone the curve, but at least it ended up pitching properly.

What you see in the picture weighs 223g including the guylines. A groundsheet and four stakes add 41g and 23g, respectively. And the two small loops of velcro to hold my two walking poles together add 6g. So just under 300g all together.

Do you suppose it will keep me dry?

[simonm]

It looks like it will keep you nice and dry. What weight Cuben?

Sadly I still have not started my pyramid build yet.

[Orion]

I used the CT1K.08 Cuben which is supposedly 17 g/m2 (0.51 oz/yd2).

[Nuts]

Looks like a nice job Orion. Turned out Very light! I know it's a bit of space (at an arkward position to loose space from) but I like the curves- and drum-tight pitching you'll get.

[GPSGuided]

Nice job! Don't quite understand the "curve". Which curve?

[Nuts]

Screen Shot 2014-08-01 at 11.54.54 AM.png (152.07 KiB) Viewed 24882 times

[andrewbish]

Thanks Orion, I have given it a 2 night field test doing the Southern Wilsons Prom circuit last weekend. Tent worked great - a little condensation on Night 1 but it just ran out and onto the ground. Night 2 had a slight breeze, no condensation at all. I'm pretty happy.

The creep I discovered was under extreme conditions. Using the tape and sew method I did, I have not seen any more evidence of creep.

Hi Redback
I found my silnylon 'mid (9' square) does a poor job of shedding wind. Have you had yours out in strong winds and how did it go?

[GPSGuided]

Thanks Nuts for that clarification.

[Orion]

Looks like a nice job Orion. Turned out Very light! I know it's a bit of space (at an arkward position to loose space from) but I like the curves- and drum-tight pitching you'll get.

Indeed. I'm just happy it worked out. Up until the moment that I pitched it I was despairing that it was going to be another one of my failed projects, and this one was going to be expensive.

It isn't quite symmetric. I had a hard time getting the fabric flat and equally tensioned when marking and cutting. I also made some really bonehead calculation errors. The last one was really galling to my pride: I forgot to account for the effect of the ridge curvature on the final height of the tent and so the pyramid is some centimeters shorter than planned. My pole setup only just barely fits.

I had some extra material so I made some rain pants. I hardly ever use my rain pants in the Sierra but I do need them on occasion and wouldn't go on a long trip without them. These don't breath of course but when I need rain pants breathability isn't as important.

My regular lightweight rain pants weigh 206g. These ones are 33g.

[simonm]

Here is another nice looking DIY pyramid.

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=93637