Corrugated plastic sheet for pack stay

I've been using that stuff in my Pinnacle as well for a few years, got it at an art supply place. It seems to work far better than the stock foam that came with the pack. I'm not sure what mine weighs (heresy, I know).

after an election they're all over the place, free, but they have printing on them

I've been using this stuff as a frame sheet in various pack builds for years. Try adding 1/8" 7075 or carbon fiber rod into the corrugations at even intervals and finish with sail repair tape.

Howdy, I was about to say just what Nathan added. Back in the early 90's Montbell used this as a frame sheet with a few pre-bent aluminum rods inserted for shape. stephan

It works OK, but after a while you may need to replace it. It can get terminally squashed. Cheers

that's why used campaign signs are good : )

>"after an election they're all over the place, free, but they have printing on them" Or, as I think of them, personalized: They are notable stiffer in the direction of the channels. And people are right, adding rods inside of those channels stiffens and strengthens them a lot. You can use aluminum aircraft alloys, carbon fiber, titanium or even unobtainium if you want to spend money, but in keeping with the cheap source of the corrugated plastic, how about wooden (often bamboo) skewers? A few cents each. The thinner ones are 3 mm. The thicker ones are 4.5 mm in diameter and were a very snug fit in each channel (different corrugated plastic can vary a bit). If using the thinner ones, I'd be tempted to wet it out with Gorilla Glue and let it foam in place. I'd leave the plastic a little large and trim to size to remove any extruded Gorilla Glue from the ends. If not, wipe it off before it hardens. And you could do it iteratively – adding more skewers until you got the stiffness / strength you want. One nice thing about cheap materials is that I have less hesitation to test samples to destruction. I learn a lot that way.

Yeah!!! That's what I'm talking about!!! Did you win? If you ran for something I commend you! What is the HEA?

Jerry, The local non-profit, member-owned electrical co-op, Homer Electric Assocation, was looking at a used coal plant to add capacity and that didn't seem like a good idea to me even apart from the climate and mercury issues – it still isn't generating any power 7 years later (Fairbanks ended up buying it). My other big success was to argue to borrow more money and build a combined-cycle natural gas plant instead of the cheaper single-cycle unit (steam generated off the 1100F exhaust generates 40% more power with no additional fuel consumption). I fight the realtors on our line-extension policy (they want to pave the state, I don't want to subsidize extending gray infrastructure into the woods) with some success, and mostly lose on civil-rights issues (there's a screaming closet case on the board and he thinks that gay-bashing somehow improves his straight cred). I won in 2008, lost getting re-elected in 2011, won in 2012 and again last year. I do reuse the signs from one election to the next. One nice ethic up here is that ALL campaign signs are taken down the NEXT day. Win or lose, the candidate and supporters are out election night and the next day taking them down. Given that, I consider the few that are still up a week later fair game for reuse in UL BPing projects, school posters, etc. One recent use was as part of a "recycled / edible" sailboat with my 10-year-old daughter. A doubled campaign sign is the deck, part of the trash can is the sail, the pontoons are shellacked baguettes, gingerbread sailors, and namesake lollipops:

I wonder if the plastic sheet + some bent Al rod (or bar) could provide a curve to get the Ohm off enough of my back to relieve the sweat issues I've been having? I assume I'd have to find some attachment or anchor points within the pack. I really don't want to start over with a new backpack.

To curve a sheet material, I'm reminded of what happens to plywood when it is wet (larger) on one side: it "potato chips" or "tacos" dramatically. To shrink one side of corrugated plastic, you could bond Ceconite (airplane-covering fabric) to one side, iron it, and thereby shrinking it. You can shoot down a Piper Cub and skin it or buy it as an art supply as my daughter's school does when they make native-style drums. If you don't mind a double thickness, it gets really easy – Gorilla Glue between the two sheets, support two ends on some boards and weigh down the middle. Over-bend it a little bit so it relaxes back to the curative you want.

Thanks for the idea (and laugh) David. Might be an interesting winter project. That is, with the imminent El Nino, San Diego might actually *have* a winter this year.

Carbon rods and bamboo skewers – Cool Ideas! Thanks!

The GoLite Infinity uses a corrugated polystyrene framesheet reinforced with aluminum rods. Details of this framesheet are given here: http://www.backpackinglight.com/cgi-bin/backpackinglight/golite_infinity_review.html#.VflqbTfouih GoLite’s Infinity Series 6.3 oz (179 g) framesheet: It is corrugated polystyrene, the same material the US Postal service uses on their white letter collection baskets. GoLite reinforces the framesheet with 7075 aluminum rods (seen as lighter areas in the photo) inserted into the sheet’s corrugations. These rods allow you to bend the framesheet to custom fit to your back the same way you would bend an aluminum frame stay in a conventional pack. One of the reasons I chose this pack was the rigidity let me get a little air flow and some relief for my sweaty back. geoff

think global, act local? nice Dave!!! maybe heat material, then bend it?

Dave, is Ceconite a specific brand of polyester sheet used for aircraft skin? I can’t find “Ceconite” at art supply stores using online search but I have found items like this: Midwest Products Clear Polyester Super Sheets

Ceconite is a fabric. You stitch and glue it on to an aircraft frame (wooden, or welding steel tubing) and then iron it to cause it to shrink. In my daughter's art class, they glued it onto wooden hoops (for embroidery) and then ironed it so that it made a taut drum head. Aircraft Spruce has several weights starting at $9/square yard. I don't know if there is a minimum order or if they might offer scraps or cut-offs for less. They have a reputation among my pilot friends as having great customer service. Caveat – this is all just a theory of mine. I know Ceconite shrinks when heated (I've done that many times) and is long-lasting (many years on a plane left outside, once painted). I don't know how much it would cause corrugated plastic to bend. And it only works if the Ceconite shrinks at a lower temperature than the corrugated plastic melts at. I'd suggest gluing two sheets of corrugated plastic together while they are bent. If that gives your back better ventilation, then you could play with a potentially lighter single layer + Ceconite. Edited to add: Aircraft Spruce also has cheaper options for non-certificated planes (ultralights and amateur-Built) such as this 1.8 ounce, 60-62" wide at $4.35/yard (probably square yard, not running yard): http://www.aircraftspruce.com/pages/cs/dacron/peelply3.php So, if you're not going to have the FAA inspect your backpack. . . .

another option i have used is a seeding tray for gardening. they have a 2" lip you have to trim off but weigh in about 1.5ounces depending on which you get. they are 2' long by 1'wide