Dec 29, 2011 at 9:32 am #1283466
I am looking a building a pack with a frame sheet just to see how it works. I have found HDPE, which I think may be what I need. What thickness would work for it?Dec 29, 2011 at 10:17 am #1817071
What do you want to accomplish with the frame sheet?
Are you looking to maintain shape, provide support a.k.a. internal frame, provide padding or some combination of all of these options?
The framesheet in this picture was made from an approximately .010" – .015" thick plastic placemat from WalMart.
The hoop stay is 6061-T6 .030" wall 1/4" OD aluminum tubing from Online Metals. The sleeves for the hoop stay were sewn to the frame sheet and are made from one inch grosgrain ribbon. The tubing stay was bent with a hand tubing bender from Harbor Freight.
Let's set some design goals and put our heads together. ;-)
NewtonDec 29, 2011 at 10:32 am #1817082
@andrew-fLocale: San Francisco Bay Area
Hey John, that looks pretty slick, what does the whole assembly weigh? I looked around at a bunch of materials last year to make a framesheet (carbon fiber sheet, HDPE, etc.) and couldn't find anything that weighed less than about 8oz. I think a framesheet is much more comfortable than a closed-cell foam pad in a backpack – it keeps the pack body from bulging out when you stuff it and protects you from lumpy items. I have a HDPE framesheet from a commercially made backpack that I used to put in my Ohm when carrying a bear can as it kept the back panel flat instead of bulging out from the cylindrical can.
AndrewDec 29, 2011 at 10:37 am #1817086
Together the frame sheet and stay weigh 3.85 ounces. The tubular hoop stay weighs 1.45 ounces and the frame sheet weighs 2.40 ounces.
NewtonDec 29, 2011 at 11:43 am #1817123
I'm looking at making a light frame with a single flat 6601 stay. I an interesting build, and I could see how it compared to a zlite frame. It looks like I may go with a 1/16" HDPE sheet from
, pending shipping costs. That translates into .0625" which is about 6 times thicker than your placemat it seems. It seems thin enough though that I will be able to sew a stay holder onto it. What are your thoughts?
Edit: Also going with 1/8 in flat stay I think, or is that too thin?Dec 29, 2011 at 12:47 pm #1817156
1/8" is probably OK but how wide of a stay are we talking about?
NewtonDec 29, 2011 at 1:03 pm #1817170
I was thinking of getting it here: http://www.metalsdepot.com/products/alum2.phtml?page=flat&LimAcc=$LimAcc
I was thinking 1/2 but I could go any width. I think I may go up 1/16 of an in. to 3/16". Then maybe 3/4 wide. This was my reasoning for 1/8 by 1/2: http://www.mchalepacks.com/sarc/02.htmDec 29, 2011 at 2:29 pm #1817204
This is where I shop for my aluminum stock.
You can take a look there for the sake of price and shipping cost comparison.
My gut tells me to try 1/2" x 3/16" or 3/4" x 1/8" but it is your $$. 3/4" x 3/16" wouldn't be that much heavier but it would be pretty tough and worry free IMO.
Personally I like the round tubing stays because of the perceived higher resistance to bending. In your single stay application tubing presents some design challenges.
I checked on 7075 at Online Metals and they don't stock the right dimensions.
The McHale Packs link has some very interesting information in it.
NewtonDec 29, 2011 at 3:27 pm #1817219
Thank you Newton. I think I will go with the 3/16 by 3/4. I really appreciate your input.
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