RSBTR 7d MTN Silnylon 6.6 now available in dark olive and blaze orange

[Michael B]

Tenacious tape seemed to stick fine to the Membrane silpoly I used. It did start peeling a little at the corners eventually, but probably more to do with me applying it to a dirty dusty tarp than anything else.

[Monte Masterson]

Since I posted this thread back in November Kyle has sold almost 1200 yards of the 7d dark olive MTN silnylon 6.6. Gray, black, orange and white are selling okay, but not near as fast as the dark olive. Better buy some of it now if you have a shelter project in mind. You never know when (if) RSBTR will get something back in stock.

I’ve found the RSBTR 7d doesn’t stick together after being folded the way the Rockywoods 7d does. The RW 7d is silicone coated one side and PU the other, but Kyle’s 7d is a supreme silnylon/silnylon with no PU junk. I’ve spent about 7 nights out with my latest 7d tarp in wet conditions and it definitely sags when it gets damp.Of course it retains some water too, nothing is perfect though. The tarp packs up SUPER small, it’s very stealthy and the material is the same weight as 0.8 oz DCF, but at 40% the price! Certainly not as solid as 0.8 DCF, but it’s definitely a strong, quality silnylon.

And yes, nylon is stronger than same weight polyester. Everybody knows that.

[Stumphges]

Monte, do you think a small mid of this stuff would require cat cut hems due to its stretch?

[Monte Masterson]

I made a half mid (Solo Hex copy) with 20d awhile back, but I’ve never built a true mid, so I’m not qualified to say. However I would most certainly think you’d want to put cat cuts on each corner seam. Since it’s thinner the 7d is harder to get taut than heavier silnylons. I put a cat cut on my 7d solo tarp ridge and then after I used it a couple of nights I went back and put a cat cut on the long perimeter sides as well in order to get a truly tight pitch. You see tents like the Big Agnes Platinum series and Nordisk Lofoten being made with 7d’s , yet of course they have frames and I believe that helps immensely with the 7d fabrics.

I’d love to make a mid a little larger than a Solomid and a tad smaller than the Solomid XL using the RSBTR 7d. I don’t have enough confidence in the design phase though, especially since the 7d is at least double the price of most silnylons and silpolys. If anyone with knowledge building mids could shed some light on it I’d greatly appreciate.

[Stumphges]

Thanks Monte, I think you’re right about the effect of a frame in the form of dome poles. The Nordisk Lofoten has less frame than a dome but has quite a few small panels, given how small it is. James Marco once wrote a nice post on here estimating the maximum height of a mid made with fabric of a given denier. I think the number of panels/ridges/tieouts would also enter the calculation. I think a mid of the size you’re thinking would work, particularly if you altered the geometry a bit to add additional facets.

A Chinese company called Knot or Knot Gear use the same fairly stretchy 20d silnylon to make octagonal pyramids that range from the size of a Duomid up to a huge one measuring 3.7 meters on the long diagonal. Same fabric for all of them. I think the eight panel design might make it work for them, although I’ve not seen the huge one in person. All of them have cut cut hems, which I initially thought was an aesthetic thing, but now think has to do with the large amount of bias stretch in the fabric. Not sure, though.

[Michael B]

You are going to want catenary cuts on at least the ridgeline seams for any tent made with a fabric that has stretch on the bias. DCF can get away with out it because it has zero stretch, but it really is the outlier. Of course you can get by without, the tent construction and pitch just have to be perfect if you want a perfectly taut tent :)

[Geoff Caplan]

A cautionary tale about super-light fabrics.

Was watching a video by a Scottish camper pitching his LanShan 2 mid on a windy ridge in Scotland.

He estimates the wind at around 40mph using Lyle Brotherton’s wind estimation method.

As he pitched the mid, one of the panels split from seam-to-seam – bottom to top.

He doesn’t know what started the rip. He’d inserted the first pole and was inserting the second on the opposite side when it happened. There’s a small rock nearby, which may have been his problem – there’s a very rough type of granite in that area.

The LanShan 2 is made of 15d PU coated ripstop silnlyon 6. Obviously, the fabric won’t approach the quality of the RSBTR7d 6.6, but then again, it’s twice the weight. SectionHiker reviewed it as a decent budget buy and didn’t mention any reservations about the fabric.

Also, when you’re quoting tear strength, it’s worth bearing in mind that lab results are one thing, but nylon strength degrades quite rapidly with UV exposure.

Seems to me that anything made of the 7d fabric would only be suited for well-sheltered sites?

[Monte Masterson]

I agree Geoff, I only use my 7d tarp when no big weather is predicted. Wouldn’t want to face winds over 30 mph with it because I’d probably suffer shipwreck. However, I believe a small, low profile, framed, 7D tunnel tent like the Nordisk Lofeten could handle it just fine.

As far as the Lanshan 2 failure, first of all the design is larger and not near as aerodynamic as the Lanshan 1. You can see how the ripped portion of the Lanshan 2 in the pic you posted is mostly a flat buffeting wind catcher. And of course the PU coated 15D silnylon in no way compares for example to the quality pure silnylon 15D Hilleberg uses on their tarps and tents. Again, I believe 7D-15D silnylons should only be used on smart designs that are aerodynamic enough to deal with its thinner characteristics, and only the highest grade fabrics. I’m just an amateur though so I’m merely speculating.

[Stumphges]

The 3F UL 15d PU/sil fabric has a heavy PU coat on the inside. I have a tent of that stuff, and it’s nice fabric, but the heavy PU coat, known to reduce tear strength, made me wonder.

[Geoff Caplan]

Yup – he was certainly pushing his luck pitching on an exposed ridge on Aran – an island stuck out in the Atlantic – with a budget tent.

The PU coated 15d nylon 6 is fair enough at the LanShan price point, but as we all agree, nothing to compare with a 6.6 coated with pure sil.

I agree that lightweight fabrics pretty much require a low-profile design if you want a quiet night, but in this case I don’t think the large panel was the issue. It was almost certainly the rough granite rock starting a tear. When a fabric that light gets a nick I suspect that all bets are off – “ripstop” or not. So any branch, rock, pulled peg etc is a real threat.

It wasn’t that serious for the guy – he just dropped down to a sheltered site and jerry-rigged a pitch for the night. But in a more remote location with no shelter it could have been very not fun…

Personally, I’m not that much of a gram-weenie that I’d take the risk. The TrailStar is 20d sil and that can take anything. It’s not really such a weight difference to upgrade the fabric. Living in an area with very unpredictable weather, I like to have a bit of a safety margin. In a US West Coast summer, maybe the equation is different…

[Roger Caffin]

Bear in mind that the tear strength of PU-coated fabric is only a fraction of the plain fabric, and the tear strength of silicone-coated fabric is significantly greater than that of the plain fabric.

Techie explanation: The silicone ‘stretches’ and distributes the load over many fibres. The PU does the opposite: it does not stretch, and it focuses the load on the immediately adjacent fibre.

So – wrong fabric or at least wrong coating for that situation. And iirc, nylon 6 is not as strong as nylon 6,6.

Cheers

[Geoff Caplan]

According to the makers of the LanShan, the 20d pure silnylon 6 used in the Pro version has 3x the tear strength of the 15d PU nylon 6 in the Standard version.

Nylon 6.6 will add a bit more.

But then, being nylon you will lose a fair bit of that on exposure to UL.

Reading reviews of the Nordisk Lofoten, a very high thread-count 7d 6.6 silnylon does stand up to storms, in a wind-shedding low profile design. One lady used it for a N to S unsupported traverse of Iceland, which is about as testing as you can get – though she did take a 200 gram groundsheet to protect the floor. Her only issue was fabric stretch intruding into the inner space when the wind shifted and hit the shelter side-on on its largest panel. Her bag got a bit wet, but not dangerously.

But more than one user has mentioned that they need to be super-vigilant about anything that might rub on the fabric when they pitch, such as rocks or bushes. Even sharp grasses might be a threat, I’d have thought. And they say that Nordisk have clearly designed the pegging system to  minimise the danger of a partially inserted or pulled peg from rubbing.

So a lot of it is down to careful design and user skill…

[Roger Caffin]

The risk from rubbing on sharp rocks is mainly for tarps and similar, because the wind can flatten the fabric on those onto the ground. The risk does not really exist for proper domes and tunnels as they have nearly vertical walls at ground level.

So yes – careful design matched to the conditions.

Cheers

[Stumphges]

I got some samples of the 7d 6,6 sil/sil from RBTR. Member John opined a while ago in a different thread on this fabric that it is too stretchy for use in a pyramid. After handling, I’m inclined to agree; not just bias stretch, but significantly more warp/weft stretch than the 20d nylon sil/sil fabric of a Duomid/Khufu-sized pyramid that I have, and I’d thought that stuff was pretty flexible.

John had pointed to the 10d mids in Locus Gear’s HD collection, where one can see the timeout corners stretching beyond square in photos, as an example of what could happen with stretchy, low denier fabrics in a pyramid. On the other hand, the 20d fabric I mentioned is also used in octagonal mids larger than the Supermid, so maybe 7d could work with the right design.

RBTR’s Membrane silpoly felt more suitable to me, but I believe some posters have found it limited in usefulness in mids. From there (0.9 oz) we jump up into several sil nylons and silpolys around 1.2 oz/yd, and right out of the SUL/DCF realm.

[Sam Farrington]

“And yes, nylon is stronger than same weight polyester. Everybody knows that.”

Monte, you’d never know that from reading BPL forums.  That is one problem with the forums.  The positions taken range so far to the extremes that it is difficult to take away much, no matter how much you’ve read.    But yes, I agree that poly is not as strong, not based on BPL forums, but just everyday experience with fabrics.

To make matters even more perplexing, the fabrics range over a broad spectrum in quality.  And it is not just about whether the nylon is 6 or 6.6.  I’ve found that the same fabric purchased from the same seller can vary from good, to OK to awful.  Sounds like an exaggeration until you experience it yourself.  I’m presently awaiting a further test of some replacement membrane silpoly to see if it meets specs.  But it looks like “crapshoot” is the best word to describe the fabric situation.

That is a big deal for MYOG, because nearly all the expense is in time and effort.  And that can not be reimbursed by returning a store bought tent.  Yes, you can fashion some primitive tests for a specific roll of fabric’s strength and durability, but sending it to a lab for professional testing is beyond the reach of most.  So for those who want to try novel designs with MYOG, it becomes a high risk proposition.    For others using MYOG with standard designs, like the mids discussed above, I’d have suggested buying one from a reputable manufacturer; but here again reimbursement of the purchase price is no salve if you have been blown away and drenched by a product made with an inferior batch of material.

It sounds like many are approaching this conundrum by using different shelters for  different conditions, and using the very lightest ones where there is a decent chance of getting away with it.  That may be fine the tent marketers, but not so much for consumers if the goal is a reliable shelter for all the conditions that reasonably could arise.  That is my goal with MYOG, because given the time and effort that goes into each tent, expected to last 5-10 years of moderate backpacking, making a bunch of different shelters makes no sense.

So it becomes a matter of using as much caution as possible with materials, as well as design and construction.  As for the materials part, while the 7D 6.6 may be superior to other 7D fabrics,  it has some drawbacks.  It is difficult to achieve a taut pitch with it, and in foul weather that is worsened by the effects of moisture on nylon.  I’ve found a taut pitch to be essential for a shelter that works well in severe rain and wind.  Couple that with the color (I thought I had black until checked the invoice and saw dark olive), the unusual challenges with sewing,  and the lack of a track record for such a light fabric, it does not seem to be a very cautious choice.

For those whos must have the lightest fabric, you are free to take the attendant risks.  And please note that .77 oz does not necessarily mean finished weight.  I’ve often found that not to be the case, as coating weights have not been accurate, and sometimes not included at all.  So you might not be saving as much weight as you think.  And unless you’re into orange, you might find occupying a bat cave rather than a light and airy tent a bit depressing.

[Roger Caffin]

In my humble experience:
In America the quoted weight is usually the fabric weight before coating.
In most of the rest of the world the quoted weight is more often the finished weight.
Confusing, ennit?

Cheers

[Monte Masterson]

The finished weight of the RSBTR 7d silnylon is 0.8 oz on my scale and it’s pretty accurate.

So as most everyone knows, the Big Agnes Platinum series tents are all made with 7d silnylon PU coated flies.The Scout 1 and Scout 2 are trekking pole supported, but the rest (Tiger Wall, Copper Spur, Fly Creek) are semi-freestanding or freestanding. I’ve searched the internet extensively looking for reviews as to how the tents perform in high winds, however most of the reviews seem to be marketing puff pieces or else they come from fair weather campers who’ve never faced the brunt of a thunderstorm with powerful 35+ mph winds. I’m really surprised to not see a fair number of disaster stories with the 7d Platinum tents in big weather. Kind of perplexing. Below is the Scout 2 Platinum.

[Roger Caffin]

most of the reviews seem to be marketing puff pieces
Expected crap.

or else they come from fair weather campers who’ve never faced the brunt of a thunderstorm with powerful 35+ mph winds.
Sounds like their target market? Fair enough. Lots of campers out there who need that sort of tent.

Cheers

[Geoff Caplan]

Come on folks, let’s get real.

Anything in 7D is going to be a highly specialised piece for careful use in sheltered locations. It’s going to be small and it’s going to be wind-shedding.

But here’s the thing, the smaller the shelter the less weight advantage you gain by switching fabric, and the weight/performance tradeoff doesn’t look all that smart.

A fabric that light is going to stretch on the bias and with moisture. So it’s very likely going to be flappy. And any kind of nick will likely propagate across the panel from its guggle to it’s zatch…

I feel it’s irresponsible of Big Agnes to release 7D versions of such big shelters  – just to win the gram war and finesse unsophisticated customers. They don’t even seem to have designed around the limitations of the fabric – the Scout 1 Platinum in particular seems to be specifically designed to be a wind trap. And there are no prominent usage warnings in their marketing.

An extreme fabric used by an expert is one thing – but I would suspect many disaster stories when naïve hikers take these Big Agnes shelters into the field. They’re selling these in Scotland, for the love of God…

Recently spotted this rant from Ron Bell on Reddit – and that’s a guy who knows a thing or two about fabric. After years of effort he’s found a high tenacity 20d silnylon he’s happy to use on his smaller mids. Everything from the DuoMid up is still in 30d. As he says:

Yeah, I know that 1.35 20d sounds pretty heavy and old school vs the uberlight 0.9ish sub <1200mm maybe, but the extra few oz. in an MLD shelter is what makes it a full 4 season shelter that will last a long time.

So how would you think this thing will perform if the wind swings around and hits you from the front …

[Michael B]

Anything in 7D is going to be a highly specialised piece for careful use in sheltered locations. It’s going to be small and it’s going to be wind-shedding.

I agree, I believe most items being discussed on BPL fit in this category. As for size and its wind-shedding capability, I believe a shelter design MUST capture a users needs accurately and material selection is part of the design process to produce a shelter to actually meet those needs.

But here’s the thing, the smaller the shelter the less weight advantage you gain by switching fabric, and the weight/performance tradeoff doesn’t look all that smart.

I agree with this as well. That being said, we are among a group who likes to cut weight with a smaller first aid kit and by cutting of toothbrush handles and whatnot – I can literally go to another active thread to see people discussing a tall person using a Zpacks Pocket Tarp to save a few oz over a slightly larger and more comfortable shelter.

A fabric that light is going to stretch on the bias and with moisture. So it’s very likely going to be flappy. And any kind of nick will likely propagate across the panel from its guggle to it’s zatch…

This will probably be a function of the shelter design rather than a generally applicable statement about shelters using this material.

I feel it’s irresponsible of Big Agnes to release 7D versions of such big shelters  – just to win the gram war and finesse unsophisticated customers. They don’t even seem to have designed around the limitations of the fabric – the Scout 1 Platinum in particular seems to be specifically designed to be a wind trap. And there are no prominent usage warnings in their marketing.

BA, and almost every other big name (REI) tent maker is clearly marketing to people who value weight savings and tent features (door arrangement, floor & headspace, # of pockets) over the robustness of the shelter agains inclement weather. Whether their customers even value robustness, it is probably likely, but without knowing their total sales vs warranty claims, we can only know what people are complaining about by how BA changes their tents from model year to model year. We could discuss whether it is irresponsible of BA to not explicitly state the limitations of its shelters – does anyone in the industry explicitly state limitations of their 3-season shelters with regards to wind loads? I admit, I don’t pay attention to marketing; I read/watch actual reviews of the products made by people I trust to be knowledgeable about such things. Buyer beware – backpacking is a hobby that requires education about risks, I think we should be very slow to foist our responsibility to be educated on to the gear makers.

An extreme fabric used by an expert is one thing – but I would suspect many disaster stories when naïve hikers take these Big Agnes shelters into the field. They’re selling these in Scotland, for the love of God…

I think the sales of BA products speaks for themselves with regard to the number of disaster stories. If there were sufficient claims to BA regarding this, I am sure you would see the evolution in their design. As it is, a majority of their products are not the Platinum or Carbon level builds, and those Platinum and Carbon level products are much more expensive for only a few oz savings, so I think I am safe in assuming a majority of BA customers are NOT buying the Platinum and Carbon products and are therefore less likely to experience a failure due to something like you are describing. The same concern can be stated for all the .5-75osy DCF shelters out there, but people are still buying them.

I like the idea of a lighter shelter that takes up a smaller volume in my pack, so I will likely still try this fabric out, first on a flat tarp, and then in a two-pole pyramid. The flat tarp will only require about 4.5-5 linear yards; this translates to approx 7.5sq yd, for a fabric weight savings of max ~3.75oz over a standard 1.3osy silnylon or silpoly. The pyramid will require approx 8 linear yards, or approx 12 sq yd, for a max fabric weight savings of 6oz. Most people would not think much about these weight savings. I would say a vast majority or BA customers would not care. but for someone making a 7.5oz tarp or a 12oz pyramid with very specific goals, those savings are not insignificant. Am I going to take my UL shelter to Scotland and set it up on an exposed bluff? Probably not. This conversation, IMO, is not for the general purpose tent user, but for someone who is informed and wants to custom tailor a shelter more optimally to his needs.

Also, Ron sells his design short. It is not just the fabric selection that makes MLD shelters 4-season worthy – it is the total design of the shelter, with the fabric selection being just one of the factors in that design.

[J-L]

MLD is using 20D silnylon in most of their products now, if not all. Even the DuoMid XL and Trailstar are listed as using 20D silnylon now.

I’ve got to agree with Michael. Most people probably aren’t buying the Platinum versions.

I recently got to see a Gossamer Gear The Two tent in person, which uses 10D fabric for the fly and floor. I was surprised how nice the fabric felt. The construction and reinforcements seemed well done. Maybe not a tent for Scotland, but probably strong enough for most of the U.S. under most conditions (obviously the design is not intended for blowing snow).

[Michael B]

Nothing wrong with 20D – we are all just weight weenies around here. I’ll own the title :)

Althooooo – I think I’ve brought this up on a similar topic before, but it might be interesting to see how much water is absorbed with a given area of 20D fabric compared to a 10D or 7D fabric. There is always the argument “nylon soaks up water, causing sag, and also causing me to carry extra weight in my pack” it would be nice to have a measured weight difference of 7D compared to 20D which have both been dunked in water and left there for a while to simulate complete saturation, and then weigh them and have a look at the effect of the weight on a sagging tarp. Hmmm.

[J-L]

Michael, I was pointing out to Geoff that MLD’s fabric has changed.

When they first introduced 20D silnylon, MLD only offered it on their smaller shelters and not their larger ones (ex: Duomid, Trailstar). Now a couple years later, it looks to be all 20D silnylon. So they’re gaining confidence in the lighter fabric. MLD’s 20D silnylon is really good and probably the best balance out there now between weight and durability.

Soaking up water doesn’t cause nylon to sag. You only need a temperature change. Studying how much water a fabric holds onto would be interesting but highly dependent on the fabric coating. I don’t know if you could draw any clear conclusions about fabric denier or nylon vs poly without the coating confounding the results. It would still make a great article for BPL though!

[Roger Caffin]

BA, and almost every other big name (REI) tent maker is clearly marketing to people who value weight savings and tent features (door arrangement, floor & headspace, # of pockets) over the robustness of the shelter agains inclement weather.
This, I think, is a slightly mistaken idea.

I don’ think the customers ‘value’ the features as such. I really doubt the ‘mass market’ (which is where those companies make their money) even understand the significance of the ‘features’. They are just persuaded by the marketing spin that this XYZ is ‘the cool stuff’. You have only got to look at the way joggers and clothing are marketed to see this.

Anyhow, the ‘mass market’ is probably not interested in handling inclement weather: they don’t go out in it. Hum – I sometimes wonder whether they are not smarter than me in that!

Bottom line: you are on your own kid when it comes to ‘adverse conditions’. The only reliable thing you can do is to ignore all the mass marketing.

Cheers
PS: there are some cottage companies which do try to be real. We know them. But they are not the cheapest.

[Monte Masterson]

“PS: there are some cottage companies which do try to be real. We know them. But they are not the cheapest”

The main stream tents cranked out in China aren’t very cheap either. Just look at the retail prices Big Agnes, Nemo, MSR and others charge and you’ll see that they’re not too much less expensive than DCF cottage shelters, especially the tents made with the lightest 7d – 15d silnylon fabrics.Take the Scout 2 Platinum at $450 for example. If you want cheap and pretty good quality look at 3F UL Gear, Six Moon Designs and Durston X-Mids.

Michael B and John made some good posts, but I wouldn’t at all be so sure that BA isn’t selling a lot of the Platinum tents. Keep in mind that even the most novice backpackers are hep to ultralight nowadays, albeit in a amateurish way. Just look at all of the mass market retail outlets that represent mainstream companies: REI, Backcountry, Campsaver, Backcountrygear, Moosejaw, Enwild and many others…and that’s just in the States. They also have a huge worldwide market. I wouldn’t underestimate Big Agnes and what suckers the consumer culture can be when it comes to marketing spin.

 

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