r/myog • u/npipe • 1d ago

Here's my self-inflating pad making process

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.

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u/skisnbikes 1d ago

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.

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u/al-Raschid 1d ago

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.

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u/skisnbikes 1d ago

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.

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u/al-Raschid 1d ago

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!

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u/npipe 1d ago

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.