Companion forum thread to:

Make Your Own Gear: Shortening a Therm-a-Rest UltraLite Self-Inflating Pad

i have an old standard w/ seam leaks so i`m going to give it a try. i have nothing to lose. but you`ve got me wondering... could i make my own pad? perhaps a self-inflater, or even an air mat filled w/ poly fill? thanks...slowhike

Yeah, the idea struck me to try to make my own pad from materials too. My vision would be a non self inflating pad that has channels built into it like an Insulmat, but with a total thickness of around 1" rather than the typical 2" or 3". Of course the size would be more similar to BMW TorsoLite. I haven't found a good source for the materials yet; not to mention the myriad of other projects still sitting in my cue. So many projects, so little time.

Jay

On my first trip with my BMW TorsoLite, I managed to pack my sewing kit directly next to the backpanel of my pack (which happened to be framed by the TorsoLite!!!). Not realizing the cause of the pads deflation, I cursed the pad all that night, and lamented how I wished I had brought my RidgeRest instead. It wasn't until a later trip when I pricked my finger on the pins protruding from my ditty bag, that I realized what had happened. I must have punctured 30 to 40 holes in my TorsoLite, all in about 2 square inches.

I tried the adhesive that came with the pad; holding the pad under water to see the air bubbles, drying, and spreading glue liberally to stop the leaks. Three deflated trips later I decided their were too many holes to fill.

Then I made a cut down ThermaRest.

After making the ThermaRest, I decided to give a go at repairing my TorsoLite by heating the snot out of it with an iron. I had nothing to loose. I hoped it would remelt the adhesive backing enough to cause the holes to close shut. It worked after a few tries. I pressed hard on the affected area with an iron on the rounded corner of my kitchen formica countertop (The rounded corner allowed me to put pressure on a smaller area so I could smash the holes closed). When I pulled the iron up each time, the inside pad layers were almost sticking to each other through the open cell foam cut outs. I wouldn't be too hard to melt the face fabric, so attempt this knowing the risk.

Jay

Good looking article one more time son, Mom

jay... my thoughts at this point are; use a waterproff material & perhaps add another light coat of waterproofing (inside). i don`t know what it would take to successfuly bond the top & bottom layers together at the edges? i would also probably want to bond the poly insulation to the shell material (two thin layers-top & bottom). a less serious glue coud be used for this part (perhaps lay the poly onto the wet waterproofing). i dont know about being able to create chambers? perhaps the same bonding meathod used on the sides would be strong enough to hold strips down the length to form chambers? my biggest question now is...what is avalible to a do-it-yourselfer that would hold fabric together airtight w/ that kind of pressure? ...slowhike

Therm-A-Rest makes a Repair Kit that uses a thermal adhesive you heat in hot water prior to applying. I've never used it, but wonder if one might use this adhesive to better seal the edges of a cut down pad or inner chambers. Might be worth a try.
-Mark

Tim,

I believe outdoor fabric suppliers, like Outdoor Wilderness Fabrics, sell heat sealable fabrics. Unfortuneately, these are intended for dry bag applications and as such are far from the lightweight materials we would like. Though I have never tried it, I don't think the standard urethane coatings can be heat sealed together.

As for the channels, they would require several 1/2" wide sealed strips down the length of the pad. These could be made by laying strips of metal (perhaps aluminum bar stock from the hardware store) lengthwise down the pad. Ironing on top of these would transfer the heat in the desired pattern... I think. :)

The question is, who sells lightweight heat-sealable fabrics??

Jay

would it have to be a heat sealable fabric? today i was looking at differant adheasives they had in the local outfitter; shoe goo,& barge cement for exsample. i don`t know that they could stand the test, but i`m thinking i`ll do an experiment or 2 just to satisfy my couriosity. people say there pretty bomb-proof adhesives & they dry flexable. ...slowhike

Here is a site I found that may be of some help

heat sealable fabrics

-Roy-

Edited by oiboyroi on 10/04/2005 00:27:45 MDT.

In the past my luxury items usually contained a blow up pillow that was only a few ounces. I liked it because of the height. Usually I like to sleep with 2 or even 3 pillows at home and just couldn't go without a pillow for a long while. Now I've gotten used to sleeping with shirt over my shoes (if I took any). So the question is what fabric could I use and what sealant to make a small(1' X 8") but thick (4") inflatable pillow. Obviously it could be made out of some silnylon or spinnaker with some bars inside holding the top and bottom apart. But is this material airtight enough for a nights sleep without significant deflation?

Hi,
Maybe this info will help with your projects. You can buy heat activated glue in sheets of various thicknesses from a very thin film to heavy duty. It’s usually sandwiched between 2 pieces of nonstick paper. Cut the size piece you need, peel one side of the paper off, iron to the 1st fabric, peel the paper off the other side, and iron to the other fabric. It’s called fusible web, and is sold under various brand names like Wonder Under, Steam-A- Seam, and others, and is sold at fabric stores, like Jo-Annes, any quilt shop, and probably Wal-Mart too. Even though it’s called fusible web, most brands are a solid sheet except some of the very lightest. Have fun chopping up your pads. A piece of that non stick paper will protect your iron and work surface from the glue and Reynold’s Parchment Paper (sold for kitchen use) works well too.
Patti

Jacob,

just carry a spare Platy bottle with closure top. blow it partially up with air for use as a pillow.

better yet, try a Platy 1/2 to 3/4 full with water (i find a nearly full Platy does not conform well to the shape of my head for use as a pillow).

Paul & Jacob,
Second the Platypus as a pillow (only partly inflated), and for comfort slip it inside a sock or roll it in a T-shirt.

I use a water wing pillow. It's only 1.5 oz and I find it works better than a platy because water wings usually have 2 or more chambers... which creates a natural place for your head to craddle. I even found one with a "flocked" inner surface... like's like a fuzzy, thin, felt surface... so I can use it without a peice of clothes on top of it.

good. better than a Platy. "water wing" - that's why i don't fill the Platy full - so that my head will compress the center & create something similar to the "wings" of your pillow. however, i'm sure your pillow is more comfortable.

I haven't read your article Ryan, as I'm not a subscriber; but I made a similar web page last year, with full instructions for converting a full-length thermarest to a 3/4 length - (beware of pop-up ads)
http://www.angelfire.com/journal2/warriors/Outdoors/Thermarest_Apr04.html

Any comments are appreciated, as I'm interested to know whether there are better methods that I could have used?

Update to web page - Long-Term Test:

1. My modified pad has stood up to around 250 days of sleeping so far. It has been kept inflated for most of that time, but it demonstrates that the new seam is plenty strong enough.

2. The topside fabric is peeling away from the foam, creating a large bubble under the surface (currently about 1 foot square). I can sometimes hear it peeling off very quietly under me. I guess this is normal wear+tear for this pad, as it is on the opposite end to my new seam, and is unrelated to modifications that I made.

Steve

going to take a look at your link in a moment.


following is just a thought, not sure that i'm correct. not sure precisely where your pad is separating, so i can't be sure that the following is not totally "off-the-wall". do me a favor, please, think about it and if you think i've erred here, let me know.


>>"unrelated to modifications"

perhaps only partly true. certainly use/wear could be some percentage responsible (don't know if these pads, unmodified, experienced this problem). the mod, however, causes a higher delta-P (pressure difference b/t no use and in use) to result when laying on the pad due to the decreased volume inside the modified pad (viz., Boyle's Law). i'm assuming here the majority of the weight of the upper body is still exerting force on the pad - legs/feet more minor contributing factor to a pad's "in-use" internal pressure.

furthermore, due to smaller internal volume, the higher pressure on the pad's outer mat'l, pushes it "out" more forcefully. that may be causing it to separate from the foam. what do you think, am i getting this right? or, am i all wet? -- been known to take a good "dunking" every now and again.

issue would be what pct of pad's vol. was removed and what pct of total body wt is still exerting press. on the pad. if pcts were equal, then no diff in press. resulted from the mod. however, if 80% of body's wt is still on pad, and your pad is now only ~60% as long, then a higher in-use int. press. results. perhaps, this exacerbated the situation slightly and caused the problem to occur a bit sooner and progress a tad more rapidly. the problem would obviously occur where attachment was weakest. that may not be near the area of modification. might be due to perhaps small inconsistencies in initial construction/manufacturing???

furthermore, let's just say ALL of the "separation" was cause by the mod (not saying it is, let's just assume), then the separation may stop at some point due to the increased pressure stresses being relieved by separation. was there any separation prior to the mod? if no, this does NOT necessarily mean that the mod caused all of the separation. your pad has also experienced more use, under which it might have separated even without the mod. guess we can't know for sure.

how much should be attributed to use and how to the mod, i certainly don't know.


EDIT:
looks like a very nice job. nice pics. good write-up. also, nice disclaimer ("cat's ear" - hadn't heard that before). did you decide to pack it inside your sleeping bag? if so, have the edges/corners damaged the bag's lining any? again, nice job.

Edited by pj on 10/17/2005 09:08:16 MDT.

Thanks for the compliments. I can understand your point about the pressure increasing. I also like the pad inflated quite hard, so high pressure is probably the cause. (Perhaps Cascade should consider using stronger foam, or treating it to strengthen its outside surfaces - eg. by letting it absorb some glue vapour?). It began as a small bubble, no more than 1cm diameter, and has steadily grown. I wonder about slitting it open, glueing it, and patching the slit.

I tried the pad inside my mummy bag, but at 20" wide it stretches the bag too much, and it curls up inside the bag causing me to roll over too easily. Further mods would be cutting and resealing the whole seam along one side, creating a shape which narrows at the foot end; and admittedly I haven't been motivated enough (or brave enough?) to attempt it! A Prolite 3 might work well.

"cat's ear" - I might have made that up. I'm as inventive with my words as I am with my stuff ;)

Steve,

i had a ProLite3 3/4 length pad. thin outer material. foam not very stiff at all. really didn't like it. sold it to a co-worker. all of my hiking (non-UL) co-workers swear by the ProLite3 however, and the fellow i sold mine to loves it.

check out Pacific Outdoor Equipment. they make some very nice pads. they are very similar in quality of construction and "heft" of materials to the BMW TorsoLite pad sold on this website. POE has more selection than BWM (just one pad). these pads are noticeably firmer than the ProLite3 and the outer mat'l is more robust/thicker - YET THEY ARE LIGHTER. read on - you'll see why.

before i sold the ProLite3, i did a side-by-side comparison of it to a POE pad and the BMW TorsoLite pad. the POE and BMW pads were very close, no perceivable diff, to me at least, in firmness and feel of the outer mat'l. the ProLite3 wasn't even close. it was playing in another league! even attempting to slightly overinflate it by blowing into it (i know, not a good idea - moisture saturated exhaled breath/air) did not make it anywhere near as firm as the other two pads. also, it just felt thin/cheap (the outer mat'l and far too easy compression of the foam) by comparison to the other two.

if you are into self-inflating pads, my advice is to save your pennies a little longer and get one of these two pads. if you want ~43", then the BMW Torsolite won't do. it's only avail. in ~30" length. The POE Hyper-Lite series (two diff thickness 1" & Mountain - 1.5", and three diff lengths - all are easy to cut shorter) have a unique hour-glass shape to the self-inflating area. the remainder of the pad is a two-layer laminate of closed cell foam. very easy to cut and reduce shape, size, and wt without cutting into the self-inflating "hour-glass". this is speaking from experience. sure is easier than re-gluing - and you don't have to wait 24hrs to test it!!! (i admire your patience.)

hope this info helps.

here's a link to the NEW PRODUCTS (pads) from POE. they're not too new at this point - saw this webpage many months ago, but they were first introduced in 2005 - i believe (could be mistaken).

POE Pads

here's a link to a retailer i've purchased from (as well as a lot of other BPL Forum participants - if i'm not mistaken)

BackcountryGear - POE items (pads amongst them - most of the pads are avail in 3 lengths on each product's/item's individual webpage

BackCountryGear's webpages are NOT always up to date. If the "Check availability" shows "Ships within 24hrs", that means that the item should be in stock. Most of the time, in my experience, it is. Sometimes (more than once), it isn't. So, if i need something for a weekend trek, i call them (ask for Doron or Eric) to find out if i can expect it to ship in 24hrs (i.e., is it really in-stock - guess website doesn't do real-time inventory?).

Edited by pj on 10/17/2005 04:51:24 MDT.