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Ply vs aluminium weights

Posted:
Wed Jul 27, 2011 3:10 pm
by GRUMPYBAGDER
Does any body have any weight comparisons for these sheet materials?.
For example if I make an 8x4 panel out of 6mm ply and another out of 1.2 mm aluminium will there be much difference?
Cheers, Mark.

Posted:
Wed Jul 27, 2011 4:56 pm
by oicu812
http://www.onlinemetals.com/calculator.cfm
There's lots of variables but here's a good calculator. I've got some alloy sheet left over from a couple jobs I plan on using on my trailer. Not sure of the shape yet but like the "Little Diner" profile. It's hard to beat aluminum for strength and weight.

Posted:
Wed Jul 27, 2011 5:08 pm
by angib
Here is some trailer weight data (page 1 American, page 2 metric):
http://www.angib.pwp.blueyonder.co.uk/t ... t-data.pdf
I didn't list 1.2mm aluminium as that's thicker than usually used - 0.8mm (0.032") at 2.2 kg/m2 (0.45lb/ft2) and 1.0mm (0.040") at 2.7 kg/m2 (0.55 lb/ft2).
Admittedly all the weights I give are for ply with some framing. 6mm (1/4") ply on its own is about 3.9 kg/m2 (0.85 lb/ft2).

Posted:
Wed Jul 27, 2011 5:24 pm
by oicu812
Thank you angib, that helps out tremendously. Fender,axle and wheels are pretty much the same as I've been looking at.

Posted:
Thu Jul 28, 2011 8:54 am
by GRUMPYBAGDER
Thats great thanks, I didn't expect to see such a big difference!.
The main reasons for thinking 1.2mm was because it was not going over a ply skin, it was going to have minimal frame work and some of it may need beating into compound curves.
I can also get shed loads of it second hand, play with it, cut it, shape it, knock seven bells out of it then give it back, all for free.
So a trailer constructed in this way (would be little more than a rolling aluminium tent) could have significant weight advantages over ply frame alloy skinning method.
Is there an alloy framed and skinned trailer on the forum, or does anyone know of the exsistance of one?.
Or is there a good reason why not.

Posted:
Thu Jul 28, 2011 10:25 am
by GuitarPhotog
My '48 is 0.055" aluminum skin over an angle-iron frame with no wood interior. A metal tent as it were.
The all metal interior is fine except for a few items to consider:
Condensation - the skin cools very quickly and I have to run a fan all night to counteract it
Sharp corners - there are plenty and I'm always cutting myself. I flag them whenever I get cut and come back and file them when I get home.
Noise - it gets quite noisy in there in a rain storm
Here's a picture of the interior storage cabinets.
<Chas>

Posted:
Thu Jul 28, 2011 10:47 am
by GRUMPYBAGDER
You've just got to love that bare metal look.
Can I ask why you chose to build that way, did you consider the more traditional route?.
I hear what you're saying about noise, I'd imagine a good hail storm would turn you deaf!.
I was intending to insulate with loft insulation then line the interior with a fabric of some sort ( still very much in the design stage ) I may need to think again and possibly add some sort of sound deadening.
I gather you weren't bullied at school then, that must feel like being shoved into a locker!.
I'd be very interested to see some more pics if it's not too much trouble.

Posted:
Thu Jul 28, 2011 11:52 am
by GuitarPhotog
I didn't build it. I suspect it was built by out-of-work aircraft workers after WWII. It's 63 years old
I plan to add rigid styrofoam insulation and headliner fabric this winter when I can't camp.
There are more pictures in my Album here.
<Chas>

Posted:
Thu Jul 28, 2011 12:05 pm
by GRUMPYBAGDER
Looks good and clearly built to last.
Definately encouraging thats for sure.

Posted:
Thu Jul 28, 2011 2:40 pm
by treemaker
GRUMPYBAGDER wrote:Thats great thanks, I didn't expect to see such a big difference!.
The main reasons for thinking 1.2mm was because it was not going over a ply skin, it was going to have minimal frame work and some of it may need beating into compound curves.
I can also get shed loads of it second hand, play with it, cut it, shape it, knock seven bells out of it then give it back, all for free.
So a trailer constructed in this way (would be little more than a rolling aluminium tent) could have significant weight advantages over ply frame alloy skinning method.
Is there an alloy framed and skinned trailer on the forum, or does anyone know of the exsistance of one?.
Or is there a good reason why not.
Check out this build for an all alloy homebuilt.
http://tnttt.com/viewto ... sc&start=0

Posted:
Fri Jul 29, 2011 3:20 am
by GRUMPYBAGDER
I had been looking for that since seeing it in the hall of fame so thanks for that, I'm currently working my way through it!.
Pretty sure I'm not capable of building anything to that standard, but then I'd be happy with something a quarter of that.

Posted:
Fri Jul 29, 2011 11:15 am
by treemaker
I'm pretty sure i could build something like his fenders with plenty of time and a LARGE supply of aluminum.
