I resumed my Challenge training today by walking to the Post Office to send my cuben Duomid back to MLD to be exchanged. It was disappointing not to have been able to take it to the Carneddau, but there was a manufacturing fault on one of the mid panel pegging points which led to a tear in the tent fabric (shown below).
I emailed Ron Bell at MLD and within fifteen minutes he had replied saying send it back and he would replace it. No quibbles, just he’d replace it. Now that’s customer service. His view is that there is a fabric defect, although I think there’s been an accidental cut in the reinforcing fabric before it was glued.
It shows that extreme care needs to be exercised when manufacturing gear in cuben, especially when it comes to reinforcing and stitching. Discussing it with Sean, he suggested that the reinforcing could have been done a slightly different way, reducing the chances of failure. I can’t see this happening to the silnylon version, which seems to be very strong.
It makes me a little more cautious about where to use the cuben version as it could be prone to catastrophic failure. I’m glad that it didn’t happen in a storm on a mountain somewhere. Click on photos to enlarge.
blogpackinglight 
It was unfortunate but at least Ron was quick to offer up an exchange.
Great service but i think Cuben is a hell of a risk for the challenge or any other long trek. I may be alone with that thought but i am yet to be convinced of its longevity.
I wouldn’t have a Cuben outer. Inner maybe ok.
Inners are fine because there’s no stress. Flys are more of an issue. In theory cuben is much stronger than silnylon. However, because it is not spun, stitching is an issue, hence the reinforcing patches of nylon. I think the cut in one of these in combination with stitching caused the failure. Holes can be more easily patched on cuben with duct tape.
I had thought seriously about taken the cuben duomid on the TGOC, but I’m not going to now, so it’s a toss up between the Scarp and the silnylon Duomid.
Only you know the answer to that one Robin. I suppose it depends on how high up you plan on overnighting and the weather forecast. I’m sure you will make the right decision.
Changing the subject a little.
FYI, Shoe Goo which i have found sticks to and repairs pretty much every fabric and shoe materials does not stick to Silnylon. Just thought you would like to know that if you didn’t know already.
Best stuff to use is Mcnet silicone seal.
I just use any old silicone mixed with white spirit. I especially like the large tubes from the £1 shops they are just the same stuff you get for a tenner from other more well known diy stores.
I bought some McNett tape but can i find it. I’ve obviously put it somewhere safe.
First of all, Happy Xmas and happy 2014, Robin!
I was casting some thoughts towards summer, as one does at this time of year…, and I was tempted to get a cuben tarp of some kind (lots of options out there). Then I remembered your post about the rip in your duomid and I thought: hang on a sec, maybe it’s not such a good idea. Have you had reason to change your mind about this, or do you still think cuben flys are not such a good idea for critical use (by which I mean: UK summit camping, where even in the summer you can get hit by quite strong winds)? I’m not sure there’s a consensus yet out there on the blogosphere regarding cuben suitability in high winds, is there?
I think the rip in my Duomid was a manufacturing fault rather than a weakness in the cuben fibre. In my experience, I don’t think there’s a doubt that cuben is strong enough to withstand high winds. However, in my view, I don’t think the Duomid is less suitable as a mountain top shelter, even in cuben. I prefer a lower profile design like the Scarp, but I don’t think it’s a black and white case.