I'm designing a 65 liters expedition pack for my brother and I was thinking about making the frame with plexiglass.

1-Plexiglass is easy to work with if you have a heat gun so I could make a nice curve for the back of the pack.

2-plexiglass is a little bit flexible so it will flex with the waist belt when it's going to be tighten.

3-(I don't really care for the weight)

BUT: Is plexiglass breacking when it's cold????
Thank you for the help.

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Cold may depend on what you are calling "plexiglass."

Read about MYOG motorcycle windshields, or just send an email to someone who custom builds these. You'll likely find more than you want to know about these materials.

So what kind of frame do YOU use on MYOG pack?

I remember someone used corrugated plastic as a frame sheet. I think others have used a combination of foam and carbon arrow shafts/aluminum tubes....your plexiglass would probably work too. Give it a try.

I believe there are various products generically referred to as 'plexiglass'. You want to do some research. The stuff you see down at Home Depot will crack and run at the slightest provocation e.g. a 'square' corner versus perfectly radiused, or an overrun saw cut.

The tradename 'Lexan' is an entirely different beast, with much better mechanical properties. A 4" ring 2" long can be rough-cut, squashed flat in a vise, and not fracture.

You need to know what product you are looking at.

I was more thinking about homedepot plexiglass...

Yeah, I saw what lexan could do (on the web) and with my Nalgenes bottle but I tough it was very hard to find some (appart from buying it on internet).
-the answer is again home depot, windows section.
(http://www.shoryuken.com/archive/index.php/t-115537.html)


Maybe corrugated plastic is too fragile. (my brother and I are very rough on our bags)But it's very cheap.

Nicolas

Yep, polycarbonate, thats what you want. You can work it with heat, but its not quite as easy to form as plexi/acrylic. The polycarbonate at home depot is about 3/32" thick and would work pretty good for a frame sheet, but it will need some shape heat formed into it to be rigid enough.

Thank for your help everyone.
I'll post a pic when I'll be done with my frame... and eventually with the beast (the bag)

Nicolas

I use aluminum. cheap, pretty easy to work with, does a great job. I use 1/8" thick by 5/16" wide stays for my lighter packs - good up to around 30 lb load. 1/8 by 1/2 is good up close to 50 lb loads in my experience. the skinnier ones are pretty darn light - about 3 oz for a pair. Unless you make your own out of a homemade carbon fiber layup, I doubt you can find anything much lighter than that that provides as much load transfer capability.

I was always going to use Kydex, since it's heat molded pretty easily. Just another of many projects that never got off the ground.

Kydex is very nice because it's thermoformable but I doubpt it has a lot of weight transfert...

Maybe a combinason of Kydex and plexiglass for a lighter result wit a good weight transfeering capacity...

Anyway, where do you buy kydex?

Nicolas

Wow, this conversation brings back some serious memories! Back in the late 80's I was mfging backpacks for a private label out of Cali... anyway, we were the first to introduce a vacuum formed/thermo formed lexan sheet for the frame sheet. It was pretty much indestructible, but was a tad heavy, expensive, and very difficult to work with. We actually started with kydex, which is the material that is used often in industrial bldgs as interior corner guards... anyway, kydex can't handle the cold, and with any flexing or impact will just shatter.
Lexan is a great material, and that old private label is still mfging that product. Thanks for the stroll down memory lane!

Today I did complete the Gibril 65 pattern but I didn’t make the fist bag out of it. If you like the design and if you don’t want to wait until I test it just send me a mail at msloudoordesign@gmail.com . I’ll give it to you only If you promise me to send a lot of pictures and constructive comments.

drawings of the bag at:
msloutdoordesign.wordpress.com

(thanks for your help everyone)

Edited by MSLdesign on 02/22/2010 13:46:08 MST.

I made a cardoard model of the bag to be sure the size is ok on my brother's back. It fits perfectly but the volume is too small (40 liters) so I'll add a top pocket and a front pocket (like the Bora from Arct'eryx but bigger). The top of the bag will open as a water tight bag.
The volume will probably be, at the end, something like 50 liters so I'll have to rename the bag "Gibril 50", I'll try to make a logo out of it to sew on the bag but it will be smaller than that, maybe G5 (don't be insulted). ;)

See pictures at http://msloutdoordesign.wordpress.com/

Pattern is downloadable on my blog but is not very accurate (not at all) but it gives a general Idea. I think that for further projects i'll make a cardboard model before drawing the pattern on computer (I like to have reproducible projects for the community)
Feel free to use it but send me pictures of your work!