Seek Outside announces Cuben (DCF) shelters

[Philip Tschersich]

Below…

[Philip Tschersich]

Seek Outside has announced pre-orders for their Cimarron (4-person w/o stove, 2-person w/ stove) and Redcliff (6-person w/o stove, 4-person w/ stove) in spruce green Dyneema Cuben Fiber (Ct2e.08). They eliminated the second zipper door to save weight and went from fixed stake loops to LineLocs. The Cimarron can be had without a stove jack.

Cimarron Ultralight

Redcliff Ultralight

(Not a production shelter:)

[Kevin Buggie]

Interesting.

Comparing the Cimarron UL to the sil version, it’s nearly half the weight (21 oz. vs 39oz), and $112 more than twice the price ($850 vs $369).  $55 extra for the stove jack seems excessive, but I appreciate locally made.

 

[Philip Tschersich]

The second zipper on the OG Cimarron was 4 oz (giving a 39 oz shelter). The new ‘light’ Cimarron in 1.1 oz/yd SilNylon (single zip opening) is 35 oz, so that may be a closer comparison to the new ‘ultralight’ Cuben version. In warm environments where you want a lot of breeze flowing through your shelter, 2 zippers makes sense. But when we asked SO to build us a custom Redcliff for Alaska last fall we requested something just like the current ‘light’ arrangement with the single zip, LineLocs, a stove jack on the back wall, etc. It was a superb elk hunting shelter, but we still were jonesing for Cuben. And now all our prayers have been answered, lol. :^)

[Dan @ Durston Gear]

DCF + Stove is a scary combo. When I was hot tenting it in a silnylon shelter I had a variety of tiny holes after a few nights from sparks settling on it. With DCF these would form much more easily since the melting temp is so low, plus it’s a way more expensive tent so it would be more painful to see happen. So I’d probably stick with sil if I was planning a stove.

[Philip Tschersich]

A friend and I had some swatches of 0.50 oz Cuben (lighter than the standard shelter material), 1.1 oz silnylon (standard SO shelter material), and some 1.1 oz silpoly (a custom fabric SO made a Redcliff out of for us) and we did a somewhat unscientific ember test on the fabrics. We took wooden matches, lit them, blew the match out, and touched the glowing stick to the fabrics. We did a few replicates on each fabric. The silnylon fared the best with the melt hole roughly doubling the diameter of the glowing matchstick. Both the silpoly and the Cuben melt holes were consistently slightly larger than the silnylon holes. Perhaps 3x as opposed to silnyon 2x (relative to the matchstick ember diameter). So all materials produced holes when introduced to an ember: the silpoly and Cuben holes were roughly 1.5x the diameter of the silnylon. If that’s a deal breaker compared to the weight savings, lack of misting and pitch quality (Cuben vs silpoly in this case), that’s up to the buyer. The ease of Cuben repair and the other benefits of Cuben are a higher priority to me, but everyone can decide what is most important to them. Cost is definitely a consideration. But all shelters will require repair when burning embers land on them. Funnily enough, your shelter choice may be dictated by your locally available wood source (our Sitka black spruce is not overly ‘pitchy’ and alders have no resin to speak of).

[Kevin @ Seek Outside]

Our Recommendations are
<h4>STOVE INFORMATION FOR DYNEEMA CUBEN FIBER SHELTERS:</h4>
Dyneema Cuben Fiber will not burn or propagate a flame however it does have a lower melting point. Due to the lower melting point, we recommend you do NOT use the anything that inhibits sparks from moving away from your tent such as a rain cap. We also do not recommend burning duraflame logs, or real pitchy wood or accelerants that can create a lot of soot. Use a spark arrestor. For the Cimarron a slightly longer stove pipe is not a bad idea (such as 6.5 or 7 ft) .

In our usage and testing, we were fine using a standard set up and standard wood found locally. The only issue we had was when we purposely removed the spark arrestor and used a bunch of accelerants , compressed logs, fatwood, etc to see how hot and how nasty we could get it. We used not only our stoves but a couple of other packable ones in testing as well.

[Jon Solomon]

I’ll bet that there are other people like me who’ve been using Ruta Locura’s cuben (DCF) Lone Peak tipis since they were briefly available in 2015 without any problems. I’ve been using mine with an old Kifaru folding titanium box stove for several years. No problems with the DCF. The TiGoat / Ruta Locura tipi design features a conical shape that sheds wind really well, better than the Kifaru design.

Glad to see new tipis in DCF hitting the market. Seek Outside makes some well-thought out gear.

OT, it would be nice if DCF or its equivalent were to descend to the price of silnylon, though.

[Dan @ Durston Gear]

“Both the silpoly and the Cuben melt holes were consistently slightly larger than the silnylon holes.”
Your larger holes in the poly (vs nylon) are likely the result from differences in the coating moreso than the material. The melting point of poly (250 C) is very similar to Nylon 6 (220 C) and Nylon 6,6 (265 C). Conversely dyneema is much lower at 145 C which is why holes propagate so large around an ember.

[Eric B]

Besides the melting point of the material, the difference in hole size likely has a lot to do with the heat of fusion.

Heat of fusion for:

nylon 66:  196 J/g

polyester 133 J/g

PET 135 J/g

HDPE 250 J/g

Nylon has a significantly higher heat of fusion than polyester so you would expect the nylon to have smaller holes.

I have no idea what the effective heat of fusion of DCF is, guessing it’s closer to the value for PET than the value for HDPE.

[Geoff Caplan]

Kevin

There have been doubts expressed by some here in the stability of Dyneema seams in serious cold, because of the nature of the bonding adhesives. See this, for example:

https://backpackinglight.com/forums/topic/103910/#post-2204504

This issue with cold may be why there are still no mainstream mountaineering or arctic shelters in Dyneema (so far as I know).

Given that your shelters are used in extreme conditions, how can you be confident that your seams won’t be failing in the cold?

[PS: Maybe someone could explain why a technical question about seam bonding has been reported for inappropriate content??:]

[Kevin @ Seek Outside]

We are sewing the initial seams then taping. We had two tents go through several large snow storms and blows in testing and then analyzed the seams for showing any potential for failure.

Given that, there still are a few things different. They will stress tent poles  and stake out points more since the fabric has essentially no stretch. Those are important things to consider at the more extreme condition end.

 

[Dan @ Durston Gear]

“Besides the melting point of the material, the difference in hole size likely has a lot to do with the heat of fusion.”
Good point. Along with this, the mass of the fabric would be important since heat of fusion is energy per mass (J/g). Even if DCF and nylon had equal heat of fusion, the same energy would create 2-3x the size of hole in DCF simply because it’s 0.5oz vs ~1.3oz/yd, so there is a lot less mass to melt.

[Diane “Piper” Soini]

$850 – $1500? You must be joking.

[Geoff Caplan]

Kevin

Thanks for responding. One of the issues that has put me off playing with Dyneema (apart from the cost) has been this issue of seam strength in the cold. I know that you guys are very serious about testing your products, so this is somewhat comforting.

Any idea how low the temperatures got during your testing?

Diane

Dyneema is very expensive stuff, and these are quite big shelters. The price is fair, and in line with other suppliers. While it remains an exotic fabric, it’s what you have to pay if you want the properties that Dyneema offers.

[Eric B]

Clearly we need a full thermodynamic ember model, and laboratory and field testing to confirm the theory.  :-)

I wonder: would the inclusion of a few panels of lightweight aramid fabric be useful to make hot tents more ember resistant?

[Jon Solomon]

Compared to a tipi made of silnylon, one made from DCF has the advantage of incredibly easy, instantaneous, yet durable field repair. Much more practical.

I’ve had the DCF tipi down to -15C (5F).

[Kevin @ Seek Outside]

Geoff

Probably  -10 F , several days at least in the 0F range.

We tested internal temps up to 150 ish with remote thermometers and as hot a fire we could get

Several probably 5 -6 snow storms in the 6 -12 inch range.

Several wind events  .. though the snow likely did more the stress seams.

Yes the material costs are certainly not inline as a percentage of sales price.

Now regarding them vs Nylon shelters at least IMO. Pricey yes, but really really nice, yes louder, but super solid. In fact, I sort of joked the Cimmaron Ultralight felt like it had actually a pole structure on the seams. Pack size via stuffing is certainly large but can be reduced with more rolling method.

This is not the first we have done with Cuben. We had made some shelters before that that now have several years of field use. We were planning years ago to intro some shelters in it , then the sale to Dyneema  happened and there was uncertainty so we abandoned the idea.

[Eric Blumensaadt]

Since I eschew center pole mid designs I’ll stick with the TT Notch Li design.

[Franco Darioli]

Can you fit 4 or 6 inside the Notch ?

[Jon Solomon]

Not to mention a wood stove…

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