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The alumuminium bar is only 15×0.9mm (barely strong enough) and the original bolt is plenty long enough for this thickness.
343 seems to be a clear favourite – and a worthy one too, nicely dark and stealthy. Any chance of getting this colour into stock soon?
Yes, though Tyvek tape will also do. If you have finished the process that Mike and Matt described, then applying this tape inside would be a good idea. I have only seen inside an MRS but I suspect that other manufacturers also seam-tape inside as well.
Here it is – it proved better to add a second guide at the rear to feed the tape straighter into the forward guide.
I can’t really tell from the photo if you have a cargo zip, but if so could you get inside and apply some of Matt’s Tuck Tape over all the seams? I would do what Mike says first, and then run that tape over all the seams inside if possible. Looking inside my MRS X2, it has some sort of sealing tape over all the seams.
When I get a minute I’ll make a little guide to bolt in front of the roller – something to feed the seam tape through as it comes from behind the roller and allow it to be steered. Will also keep the tape at a flatter angle to the fabric and closer to the gun, and add a little drag to keep it taut. Fiddling around with fingers and thumbs is too awkward.
I haven’t yet had time to do more than a couple of hours testing, but it’s quite practical to use the gun in one hand and the roller in the other, following directly behind the gun. It also seems to work well, though it will need more practice, to wrap the seam tape over the roller so it trails behind, and use the roller in your palm and two fingers to guide the tape. This worked on one test on a flat surface, and with practice should work on a curved surface.
Also, you can tack-weld the tape in place at various points along its length, the same as you do with arc welding when you know things will otherwise buckle out of shape. Or start welding from the centre and move towards the ends, trimming to length when you get there.
Taping the two pieces together prior to welding is probably key, and finding that you can do that without melting the gaffer tape makes things much easier. All the heat goes into the tpu coating, and the other side of the nylon is not hot.
After becoming disillusioned with my broken down sealing tools, I sat and watched youtube videos on hot air welding guns and then went and bought
this one from ebay.I’ve only had it a couple of days and only played briefly with it, but I’m very impressed. It comes with various bits including a 20mm flat nozzle and a silicone roller, is nicely balanced in the hand and should be very easy to use with a little more practice. Bonded joints are strong and uniform, and very quickly made. It’s very practical to tape two pieces of fabric together with gaffer tape the full length of the joint and then weld the seam tape on the tpu side (as for the boat tubes) – the gaffer tape is barely even warm when ripped off. This should make it a doddle to line things up properly. Works just as well on that 30D/100gsm white fabric from Seattle Fabrics as on Matt’s 210D/280gsm fabric.
In summary, this is the bee’s knees. A very valuable addition to the toolbox, and it gives me huge confidence that the finished boats will be strong and survive anything we might do in them.
The tubes folding up was an issue even in flat water, and I imagine that in broken water it might well get swamped. Part of the trouble with the MRS X2 is that it doesn’t have a top-up valve usable while paddling – you have to pull up on the bank to top up the pressure. If I were to keep the boat I would definitely add one and that would partly, though only partly, solve the pressure problem.
The other thing is the length – we didn’t notice it too much on the first day but on the second day the boat was quite cramped. Worse, it became obvious that the forward seat needed a backrest, and without that Alex was knackered by the second evening. For long trips the boat needs to be long enough to stretch out in, but then it becomes an inflatable kayak – and needs the same high pressure to keep stability.
Apart from moving to different fabrics and higher pressures (or legless paddlers – in the Gnu you’re supposed to kneel with your legs tucked underneath you) I can’t see how to solve the problem with a boat that is still a packraft that can be carried in a rucksack.
Rather more than imitation, it looks almost like a straight rip-off. A whois shows the site was registered on 5.01.2017 by a Nick Kowalski in Somerset. The videos and instructions are “available after purchase of a kit” – why are these not public??? He will sell you a sample pack of red, blue and black fabrics, but only sells the kit in green. Hmm. While many of us are fans of green boats, the shade he offers looks more neon than stealth.
Take it as a compliment Matt, and keep going. You’re doing an excellent job.
Could I make a suggestion here. I plan to use Exped flat valves on my two boats, partly because we have Exped sleeping mats now and it makes sense to use the same schnozzle pump for both. These are excellent little valves anyway, quite unobtrusive and well proven to be reliable. The only negative is the cost – you have to cannibalise an Exped item to get them. If you want a deflation valve as well as the inflation then an air pillow is cheapest, or if you want just the inflation valve (which can also deflate) then a replacement tube for their TT mats is cheapest (at least in the UK). Once cut out, the valve will have a large circle of TPU fabric making it easy to glue onto something.
On the boats I will use one inflation valve near the stern, and use that to release the peak air pressure and the zip to release the air volume. The inflatable floor will have another, probably also near the stern so as not to be blocked when the boat is rolled up.
Something like Pantone 342/3425, 343, 357 would suit me. Something dark and stealthy rather than light and bright. Alpacka and MRS both do a nice enough green. I have an MRS X2 in green which blends into the scenery on the bank.
I understand that complementing the other primary colours is an option to consider, but I imagine that most peope considering a green would want the whole boat in green. For myself, I will never take this to a river by car for a day with other boats and then take it home. It will always be in my rucksack and walked into places, usually solo, so I’m quite keen to keep in sync with natural forest colours.
What an excellent inflatable floor. I wouldn’t want it self-bailing in the UK climate, but I plan to start my two rafts in March and will definitely incorporate this.
Thanks for the info and photos.
Yes, that’s the one. I’m in the process of bodging up a fix with some PVC waste pipe to slide over the whole length, and some silicon tubing to make a collar around the hot end. It will end up very strong and usable, but will still be a bodge and I really can’t recommend it.
I should add that I had no idea that extremtextil’s current tpu fabric is different to the lot from 5 years ago, and it was only discovered when testing to find the right temperature for the new tool. In the end I had to abandon that project and write off the money and time spent on it. This was hugely irritating, but even though these were going to be multi-chamber sleeping mats to guard against punctures, a systemic and total failure in winter means possible hypothermia and worse.
If not for this discovery I would have bought the plans off Matt and the fabric off extremtextil, as shipping to the UK from Germany is considerably cheaper than from Canada.
As it is, I’ve bought one kit from Matt and will buy another a bit later. I need to be sure that a hard hit on boulders will leave it floating in one piece, and the extra shipping cost is insignificant compared to the possible consequences.
OK, I’ve just seen that post and added one for the iron I’m using. The original 70den/170gsm tpu fabric I bought 5 years ago from extremextil welds very well at a temp of around 280C, but the new lot just melts at anything more than about 160.
It seems to me that anything extremtextil do not list as “high-tenacity 6.6” is only “nylon 6”. Matt mentions the difference somewhere on this site, and I will not trust the “6” for anything. If you bounce on a sleeping mat I would expect it to break and leave you on the cold ground for the night; if your raft bounces against boulders at speed then I would rather be on shore with a camera than in the raft trying not to drown.
The soldering iron I have is this: ebay 58w iron, very cheap but effective.
It uses solid tips of 6mm diameter and I made a welding shoe from heavy copper tube, hammered flat and smoothed off to 11mm width. Having seen the clover iron I have bought a large shoe and will soon add a set screw to the iron heater to hold the clover shoe in place.
The original 70den/170gsm tpu fabric I got from extremtextil 5 years ago welds nicely at approx 280deg C, but the new lot just melts at anything more than approx 160C (the dial is not marked finely).
This is interesting. I also got some of their 40den/70gsm fabric, as at the time I intended making two sleeping mats: one from 70den and one from the 40den.
Before starting I made test strips 2cm wide and welded them together at different temperatures. I am now using a converted soldering iron with temp control from 150C to 450C, and a shoe 11mm wide. I found it was virtually impossible to get a sweet spot where it was hot enough to weld but cool enough to not melt. And whenever it seemed to be a success, a hard pull would break the fabric at the juncture of the weld to the unwelded part.
This is exactly where Exped mats fail – frequently the baffles let go inside the mat. My last was UL with 20den fabric, and holding it up to a strong light let me peer inside and left me quite certain that the baffle failed at that juncture.
Extremtextil list the 40den as having a melting point of 163C. What are you using to weld with?
It seems that Extremtextil get in different lots but list them under the same description. About 5 years ago I got some 70den/170gsm tpu nylon to make a sleeping mat, and it heat welded fine. A couple of months ago I got another lot, listed with the same desription, but it just melted when it should have welded. I assume this is the difference between nylon 6 and 6.6 – they melt at radically different temperatures.
I think the onus needs to put on them to either send the right stuff or say that they haven’t been given those details to pass on. They will do half metre lenghts for testing, but shipping is expensive to the UK for small amounts.
