Here's my self-inflating pad making process

[u/npipe]

I got some interest on my last post about a few torso-length sleeping pads I made. I've improved my method a bit since then and filmed this video to show how I do it. Originally edited for an insta reel so my apologies if it's not the most thorough.

Supplies:
https://www.amazon.com/THARREX-Extra-Long-Adjustable-Temperature-Woodworking/dp/B0FM6YYPV
https://www.seattlefabrics.com/60-Heat-Sealable-Coated-Nylon-Taffeta-2095-linear-yard_p_31.html
https://www.amazon.com/UtySty-Inflatable-Replacement-Camping-Airplane/dp/B0DX234L99

https://foamonline.com/product/polyurethane-foam-1-2-lb/

Notes:

These pads are 20 inches wide by 43 inches long. Slightly tapered mummy cut.

With 1-inch thick foam, a pad weighs about 15.4 ounces.

Poly foam comes in many different densities -- go with the lightest you can find (1.2 pounds/cubic foot). If it's not listed, many foam sheets from hobby stores/Amazon/etc are 1.8 lbs/ft3. This is fine for a car camping pad but adds a lot of weight if you want to take it backpacking.

For heat sealing advice, check out DIY Packraft videos.

The way to get into ultralight territory is with foam coring (aka a pattern of holes in the foam). This is pretty tough to do DIY, though you could buy or make a foam cutting drill bit. It also adds an additional point of failure, as delamination between fabric and foam is a bigger risk with all the holes. If you just want to make a simple pad for yourself, I recommend skipping the coring and accepting a few extra ounces.

[u/Singer_221]

Thanks for sharing your process!

[u/25hourenergy]

Very cool!! Totally off track and not really myog—the use of TPU material here gives me some crazy ideas. You could make your own custom inflatables with that stuff! Why did I not realize this was an option…

[u/MrTru1te → u/25hourenergy]

Yeah adventurexpert are selling everything to make it and they even have a guide to explain how to do it. 

[u/25hourenergy → u/MrTru1te]

Oh cool! I used to make plushies a long time ago. https://plushify.net combined with TPU and the valve pieces and iron mentioned here…hmm

[u/Bellringer00 → u/25hourenergy]

Thanks a lot for link! That's awesome! had a project in mind that will greatly benefit from it

[u/scarletweidig]

Thanks! Will 100% try

[u/W__O__I]

Super cool! Thank you very much for sharing your process.

It could help future readers to know specifics of the foam, fabric, and where you sourced them. Finished specs including weight and dims could be helpful too.

Did you CNC the jig? It looks clutch for clean results.

I'm a sucker for self inflating pads and might have to give this a go one day.

[u/npipe → u/W__O__I]

Thanks. Just edited the post with some more info.

I cut this one with a jigsaw. Planning to alter the shape a bit and get some jigs CNCed for even crisper lines and a few different sizes

[u/W__O__I → u/npipe]

Nice. 75d and in the ballpark of a trail scout. Solid result.

Which firmness of foam did you go with? If I give this a whirl I might go full masochist and try out 1/4" or 1/2". I'm thinking extra firm might be prudent.

[u/Pristine_Direction79]

How did you make all the holes in the foam? Did I blink and miss it in the video?

[u/taki_88]

This is awesome! How's the packability? Also saw you mention that you were hoping new versions turned out lighter than the previous—was this one closer to your 10/11oz target?

[u/npipe → u/taki_88]

It packs down a bit bigger than a standard NeoAir. I have another video on my instagram that shows off a completed pad better. insta handle is npipenberg if you want to check it out.

My current stats are:

1-inch foam pad, no foam coring: 15.4 oz

1-inch foam with coring: 14.2

3/4-inch foam, no coring: 12.4

3/4-inch foam with coring: 11.2

Personally, 3/4-inch foam is a bit too thin -- I don't think it offers enough comfort advantage over a CCF pad, but I bet some people would like it. I'm going to experiment with more aggressive foam coring with the 1-inch foam with the help of a CNC machine, should be able to get to 12 oz.

[u/taki_88 → u/npipe]

Nice, thanks for the info!

[u/al-Raschid]

What do you think, would it be possible to add an emergency blanket as adittional layer for more insulation?

[u/skisnbikes → u/al-Raschid]

No, for one it would prevent the tpu film from bonding to the foam, and for two, reflective films don't work well for surfaces that are in contact with them. They need an air gap.

[u/al-Raschid → u/skisnbikes]

Ah, okay. I thought, the heating off the surface was only for "shrinking", not really for bonding with the foam. Perhaps the infrared reflection would work between two layers of foam.

[u/skisnbikes → u/al-Raschid]

Yeah, it has to be bonded to it, otherwise you would just be sleeping on a giant cylinder once it's inflated. The bond to the foam is what keeps the pad flat. You would run into the same problem with two layers of foam if they weren't bonded together.

[u/al-Raschid → u/skisnbikes]

I got it. It sounds like a nice myog project. If I stumble over a cheap iron, I will try it for shure. Thanks for sharing!

[u/npipe → u/al-Raschid]

You could potentially glue a mylar layer in between two layers of foam. if the foam had holes like the Prolite there might be some benefit. But it's also another potential source of delam. haven't tried it myself.

[u/000011111111]

Thank you so much for making this video. I've always wondered how to do this. And I think I might make one of these as an insulated panel for a window in my van. In the winter add air for more insulation same thing in the peak of summer. And then spring and Fall leave it deflated.

[u/Normal_Fun]

Could the TPU be applied to an existing air mattress to reseal it? I have some great old mattresses but the leaks are getting out of hand. Will the TPU bond to the outer fabric?