Chris

Matt: AWESOME link to this man’s quest to build a 2 lb float tube. I read through all 22 pages of posts spanning 5 years of research and design. Fascinating stuff. We lost a good one when he died.

Wow! Some seriously awe inspiring pictures, we have a different setting of beauty here in Hawaii, so when I get to see authentic photos of such luscious and diverse, beautifully blanketed land it truly is a treat so thanks for posting them! How did everything go with the V3, were there any things you learned from the expedition?

My favorite seat back, and the easiest, is a Crazy Creek folding camp chair. Not exactly a back packing item, but I can set a 2″ thick square boating flotation seat pad into the raft, top it with the crazy Creek chair and my daughter is up above the water and happy. Commercial versions that support the back and wrap around the hips are not popular among the hardcore here in Fairbanks. I bet Matt can develop something much better! The whitewater hardcore I know prefer a good kayak back band, supported with attachment loops or D-rings high on the inside of the raft. If using D-rings, they also attach their thigh braces to the same point. (I’m still looking for nice 1″ (25mm) aluminum D-rings, chrome rust, and the Titanium ones are a bit rough edged (DutchGear.com)). If using webbing one has to think through the connection so knees and back straps are connected and pulling against each other, not both building pressure on the side attachment patches in opposite directions.
Can’t wait to get my V3 built! Lets see, 1000D or 420D, that’s the question?

Yes indeed!

Thanks, Rob! Yeah, the inflatable floor will be a removable insert instead of integrated into the boat – it’s just easier that way.

Awesome – it should be within the next week or two. Thanks!

Looks great! Wider seams, appear to be almost 40 cm wide?

Looks great! Wider seams, appear to be almost 40 cm wide?

Very, very nice.. Have to get me one of those..

Hi Hugh – I’ve updated the post to include the main differences. Thanks!

Thanks, Eliot!

They are heat sealed together 🙂

Hey Matt

Sorry to hear you have had people stealing your designs for their own profit, that sucks! I can only imagine how much time and effort it must take to plan and test your designs – the V2 packraft I’ve made from your kit has handled beautifully without any leaks since I first made it. I was hoping to purchase plans or a kit for the 2-person voyager in order to make it in time for training for and competing in Godzone, an adventure race I am doing next year in NZ. When do you think kits for the 2-person will be online?

Thanks for your hard work

Hi Todd, I would start by reading the Fabrics, Tools, and Valves sections of the FAQ, above, and maybe check out the Forum as well, as there are some pictures of rafts people have made. Also check out the inflatable catamaran raft at http://www.cubenmaker.com. For seam sealing technique, check out the videos in the How-To sections above. Cheers!

Great! I hope to have it ready in the next week or two, but I can’t guarantee it.

Hi Tim – it will be approximately 4 pounds. Cheers!

Thanks, Brian – that means a lot to me! Best regards

Hi Mark – I will be designing a V3 version of the Ultralight packraft, but it will be slightly different because it will not use double-sided TPU fabric, so it will take a bit longer.

Yess Matt thank you so much! Deffinately excited about this and the next update, I have already begun imagining a way to add clips to the bag so it could double function as a drybag! Such amazing work your doing, I for one appreciate it!

I am especially interested in your connector that fits the fine Boston Valves. They are great valves, but an odd thread I have not been able to successfully fashion on my lathe. Worth the price of a kit, though I made my bag out of silnyl not TPU.

Hi Greg,

I think this is a better product in general, but its size makes it a bit awkward to use sometimes, so it’s a trade-off. Future DIY Packrafts will be designed to be easier to construct with irons this size.

Cheers!

Matt,
Before you wrote this blog, I decided to try one of the model aircraft heat sealing irons. I chose the Top Flight because it has a narrower bottom, and I thought it might be useful sealing across double width seams, where tubes join the floor, for example.
Using my inexpensive infrared thermometer (an instant read oven meat thermometer works just fine too) I found it heated to 198 degrees C. On removing the plastic thermostat knob, I could reach into the brass stem with a fine jewelers slotted screwdriver and adjust the thermostat. Turning the inner screw counter-clockwise increases the temperature. It doesn’t take much. 1/8 of a turn may be all you need. Double check it on a piece of TPU fabric, of course. I’ll post a picture on the forum.
I have also ordered one of the 220 volt leather irons from Aliexpress. I’ll let you know its dimensions and how it works when it arrives.

hello,
how much power you need for welding the tpu?
are 20W enough?
in germany i can get an iron which will make 240 till 280 grad celsius.

hello,
how much power you need for welding the tpu?
are 20W enough?
in germany i can get an iron which will make 240 till 280 grad celsius.

Hi Michael – I use the side and the bottom and the tip of the iron when working on the seams, depending on the situation. You can iron a strip narrower than the bottom of the iron by ironing over a convex bowl or narrower form (details in the V3 instructions), and you can also try putting masking tape on parts of the iron to insulate areas you don’t want to use. Cheers!

How much power you want depends on how much area you want to weld at once. A soldering iron may melt the material together, but when a complete boat consists of maybe a square meter of welding, the tip of a soldering iron makes maddeningly slow progress.

I have experimented with various soldering irons attached to a rheostat, an antique one with a big chunky copper tip worked the best. I also tried the clover iron, it gets the job done but is still slow at 40W. The whole thing of having a heating element far from the iron surface is maddening, as you are relying on all the heat you need for bringing fabric and underlayment up to temperature to travel down a skinny shaft. In addition, having this “lag” between your heat source and sealing surface makes for an iron that when laying about overheats, but when used cannot produce enough heat to weld efficiently. For example, the clover must be left sitting idle on it’s medium setting as to not get the tip hot enough to melt the nylon at initial touch. however, once in use it must be turned up to it’s highest setting to keep up with heat lost through the tip.

Matt’s suggestion of using the black baron heat sealing iron makes sense, as the heating coil is in the iron itself, and it appears to have at least a little thermal mass to it. I.e, the heat you make is the heat you get at the tip. I am waiting for the “21st century” cover rite iron to come in the mail, supposedly it keeps a temperature within 3 deg f.

I would rather use a clothing iron before I used a soldering iron!

In the last 12 months, I have built 4 cat-a-rafts and experimented with a few small pillows as well. I had 2 failed attempts, one reasonably functional raft and finally arrived at a design I am happy with. The point of that is that I have sealed a bunch of linear feet of fabric.
I started with the Mini Clover and graduated to the “improved” mini clover. (aluminum foil wrapped shaft) The out of the box version is painfully slow on 210 D fabric. The improved version is significantly better but it still requires waiting. It heats up to where it melts on contact (not good) then cools to where it’s not sealing requiring one to wait for it to heat up. Wait too long and it melts on contact. Not long enough and you don’t get much sealing done. The mini Clover does work much better with the lighter fabrics but they melt much easier when the iron is too hot so greater care is required.
Recently, I have been struggling with getting a pillow to hold air overnight with weight on it. If I can do that then I can build a raft that stays hard for long periods… I considered that the problem might be the new batch of fabric – especially the new 3 oz 40D. I mostly suspected my technique. I thought that I might be weakening the fabric at the seam edge when I hit it with a too hot iron. I suspected I was causing just enough damage to allow a very small amount of air seepage. As soon as I saw the video of Matt with the Black Baron I ordered it on Amazon. It was $26. As soon as it arrived I cut off the edges and resealed my last two pillow experiments. I achieved a good seal and no leakage. I put a 10″ x 10″ x 3/8″ steel plate on top of my most recent 40D experiment and it held air overnight. Mystery solved. I am now waiting for another batch of fabric and looking forward to working with the Black Baron iron. It is much more robust than the Mini. I broke my first Mini Clover after a decent amount of use and my current one is loosening up and likely to break in the near future. I don’t see how one could break the Baron. The adjustable temperature really helps and the larger mass holds the heat. As noted above, the Baron’s size helps solve some issues but at times can be a hindrance but overall, I think we are on to something here. Ron Samber

Yikes, that sounds scary! I’ve never used a sock, so maybe that’s the issue – wrapping an iron in an insulating blanket will certainly keep a lot more heat in. I’d avoid using a sock in the future.

I recommend against the 21st Century Iron altogether. Mine actually didn’t get hot enough and it lost its heat too quickly due to the shoe having less mass than the Black Baron iron. The 21st Century Iron looks good on paper and I’m sure it’s great for the thin fabrics that airplane modelers use, but for this application I don’t think it’s the right tool.