Question about shelter fabric weight

The top ultralight tent designers from ZPacks, Tarptent and Durston maintain that 0.5 oz DCF performs well enough in all but the worst conditions, but I’m in the MLD camp of .74 to .8 or nothing. As MLD states in their Fabric Mojo: ‘we no longer offer DCF in the ever so slightly lighter and much more fragile .5 or .67 versions. Compared to .5 and .67 DCF. the .8 DCF is 2X stronger and offers 3X longer service”.

The lighter .5 DCF is a little cheaper and perhaps most of all it provides the lowest weights (and volumes) for manufacturers to display to buyers. .8 DCF is bulkier for sure, however it only adds 1.5 to 3 oz to most shelters. The Duomid is heavier than the Ultimid also because of a much beefier build throughout.

You might see replies that extoll the virtues of .5 DCF and spin it to be on par with .74 to .8. Believe what you may, but to me there’s MLD and then there’s everything else.

Not sure what “stronger” means is this case but the issue with Dyneema is not strength —  0.5 ounce is way more than strong enough for wind/rain/snow without breaking — but rather mechanical breakdown over time of the Mylar layers. Doubling up on the Dyneema fiber doesn’t help much is this regard and doubling up on the Mylar certainly helps more but our experience is that you will not get 3X longer service out of 0.8 compared to 0.5.  We, until recently, used 1 -ounce for flooring which has roughly twice as much Mylar as 0.8 and no way does it last 3x as long as 0.5. So much depends on storage and it is hard creasing that kills the fabric. The other thing to understand about DCF and relative lifespan is stress though the bias — force lines diagonal to the fiber lines — and DCF fiber simply has no way to resist that other than by the mylar which is why you see stretched, saggy DCF shelters after extended use because the Mylar permanently deforms.

Monte—thanks for your input.

Henry, you too!  Though this conflicting information keeps me confused. :). Your description of the stretched/deformed nature of the doumid after a few very very windy days in Alaska is accurate. Though it still performs perfectly and can get set up pretty tight still.

A follow up for you: is the material used by you and other companies essentially the same (weight dependent obviously)?  DCF at tarptent is the same as at Zpacks is the same as at HMG is the same as at MLD?  Essentially, as the consumer we are just picking the design we like best and all the material is comparable?  Nobody is using some proprietary material?

DCF 0.5 osy is the same for every company. As is 0.8 osy.

There was a thread a while back on BPL/reddit where 0.5 osy tents suffered holes from hail. We later learned that the DCF tents that suffered such holes were really old tents with lots of miles on them and perhaps had used an older mylar design. So the newer 0.5 DCF tents may fare better is the belief.

There is a belief that 0.8 osy fabric may fare better with hail. I am not sure if there is enough data to support that.

So far – all the data on DCF tents suffering holes during hail has been 0.5 and 0.67 osy tents. You can search Reddit etc for such threads. I have not seen a single thread where 0.8 DCF tents have suffered holes from hail.

I think it all depends on your style of hiking. If you are the kind of person who walks all day and uses the tent as a shelter for the night AND you don’t camp in exposed areas like above tree line AND you do not set up tents during the day to escape rain/hail etc – then 0.5 osy will be fine.

If you are the kind of person who camps regularly above tree line in exposed areas – like SHR, YHR, WRHR etc and wants to set up camp during the day when it starts raining etc, then 0.8 osy is a better tent choice. I was camped in totally exposed area in WRHR and it started raining at 5:30 AM and went on till 8:45 AM. This was in my 0.5 tarp and I was praying that there would be no hail.

If I was buying a new tent now – I would buy a 0.8 DCF tent. That is just me. I will keep using my 0.5 DCF till it dies. But, I will be very careful where I camp – but, sometimes you are forced to camp in exposed area like what happened to me on the WRHR.

Jon, DCF comes in different compositions — layer arrangements — and there in a naming system to identify the composition and thickness. Here is a screen grab from a Reddit thread some time ago which lays out the various weights and compositions. Note that the “E” type material uses a much thinner Mylar than the “K” type material.  “E” is lighter but in no way stronger/more durable than “K”.

As Henry says, 0.8 oz DCF won’t have a 3x longer service life than 0.5 oz because it is just the same stuff but with more Dyneema fibers (which aren’t the main limitation). Even MLD who made that original claim have walked it back. On reddit they clarified that by saying something like ‘that 3x claim is referring to our largest shelters, whereas in 1-2P shelters the difference might be as little as 10-20% [approximate paraphrase, not a real quote]. 0.5 oz is fairly similar and not “much more fragile“.

With regard to hail, we’ve had lots of reports of our shelters in serious hail without damage.  I’m not sure if this is because the newer mylar is more resistant, or because our shelters have steeper roof panels so they deflect hail better, but either way, hail has not been an issue. I’m sure at some point there could be damage, but 0.5oz DCF has held up well in our tents through dozens of customer reports of hail storms. Here are a few customer photos of hail without issue.

0.8oz DCF is nice stuff too, but it is over 50% heavier for not a lot of benefit. You’re giving up a good portion of the weight savings of DCF for what I think is a pretty small difference in service life. Rather than make all the fabric heavier, a bigger factor for longevity is how well the material is reinforced and oriented. If you orient 0.5oz so the fibers are in line with the stresses and put DCF backed tape along seams where it is not, then you can improve the lifespan.

It is good to know that 0.5 DCF tents are doing good with respect to hail – at least in your designs.

“0.8oz DCF is nice stuff too, but it is over 50% heavier for not a lot of benefit.” – misleading though. You meant the fabric weight which is true – but a Zpacks Duplex is 17.9 oz in 0.5 osy and 19.9 in 0.8 osy – so not 50% increase in overall weight of the finished product. (with same tie out thickness etc).

We are pleased to offer custom shelters made from .5 DCF. Ultimately, it’s up to you to assess your needs and weigh the trade-off between weight and durability. The .8 DCF is more durable and offers a longer service life, which might be beneficial if you’re considering a Supermid or using any size Mid for four-season winter camping. You may also prefer a sturdier #8 zipper (MLD standard) over a #3 or #5. Additionally, a stronger, less flappy vent with a foldable wire wand on a larger Mid can add a bit of weight but enhances weather resistance. There are many excellent shelters available made from various types of DCF. We take pride in being the oldest company still producing DCF shelters.

Although the Reddit post is 2 years old, in it Ron provides a more in depth analysis as to why he chooses to use only .8 DCF. Says on small mids it might be a 1.5 times longer life span, but on larger mids far more. Don’t see anything about a 10% to 20% increase in longevity, must be on another thread.

https://www.reddit.com/r/Ultralight/comments/unhv97/your_experience_with_05_vs_08_dcf/#:~:text=What%20might%20be%20interesting%20is%20to%20have%20a%20hybrid%20DCF

Even if the 0.8 just provides a 1.5X gain that’s a lot on a $600 plus tent. Only adds about 2 oz weight on most small to medium size tents.