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aluminum help

PostPosted: Fri Feb 13, 2009 9:42 am
by bfitz
I'm having a hard time finding information for how to design for aluminum. As I've never worked with it, I have many questions. A couple of biggies are:

-Since Al and wood have radically different themal expansion rates, how should Al be adhered to a wood skin? I would have been tempted to epoxy an Al skin to a wood underlayment. Someone said the epoxy would inevitably fail due to thermal expansion.

-What's the best way to deal with skinning a 5' wide trailer with 4' Al? Make a seam down the middle? Have several 4' bands running left to right (numerous seams perpendicular to the trailers centerline)?

-How much should I epxect to pay for a 4x12 sheet of 18gauge? 4x10?

It seems like there would be a sticky with info like this. Am I missing something?

Many thanks,
Brian

PostPosted: Fri Feb 13, 2009 10:00 am
by madjack
Brian, we don't adhere our AL skins to the body/roof but rather "float" them, allowing the vents/trim/doors/fenders/lights/etc to capture and hold in place...others glue 'em down...............

...run your seams side to side...give yourself about a 2" overlap and use a good quality sealant and a SS screw about every couple of inches...this gives us 2 seams on a 5x9 camper, which allows us to cover the camper with 2 sheets of 4x10 AL...........

...you should be able to buy your sheets for under 100bucks/per...I paid 65 bucks for 4x10x.040 a couple of years ago........
madjack 8)

PostPosted: Fri Feb 13, 2009 11:04 am
by planovet
There are several threads on the decision to glue or float. Seems to be a personal preference. The further south you go (and hotter you get), I think the best option is to float.

Thread 1

Thread 2

As far as cost, I would guess it would vary on where you live. I bought some white 5x10 .040 aluminum recently for my roof and paid a little over $100 a sheet. I plan to float it.

PostPosted: Fri Feb 13, 2009 11:24 am
by bfitz
Sounds like floating is the way to go.

With respect to the joints...will a lap joint acros the roof be sufficient to lock out water on the highway (even with sealant) or should I hit the edges with a brake to interlock the sheets?

Also, it seems that if the Al is floating, it will destroy (through expansion cycles) any seal at the edge of the roof. My first thought is that a rubber gasket installed under the trim might work? Should I stick to silicone caulk?

5x sheets...I haven't found these locally. Anyone know of a supplier "near" Battle Creek, MI? Seems they'd save a bunch of work.

Thanks,
B

PostPosted: Fri Feb 13, 2009 11:35 am
by madjack
...have used a lap joint on a couple of trailers with no problems...commercial builders do this as well...we used auto windshield sealant/adhesive for overlaps/hinges/lights/ect...used regular RV putty tape under the edge trim...has all worked wonderfully well so far.............
madjack 8)

PostPosted: Fri Feb 13, 2009 12:42 pm
by dmckruit
I have found several suppliers in my area (Pittsburgh and Eastern Ohio). You can get 3003-H14 mill finish aluminum (0.032) thickness in 4'X10" sheets for around $45 a sheet picked up. This pricing is as recent as last week.

The only thing is that they package on skids and not rolls, so I will have to put the wheels and lights back on my trailer and make a trip to get the aluminum before putting my walls up.

PostPosted: Sat Feb 14, 2009 12:19 pm
by Mark McD
Airparts has 4' wide aluminum sheeting, available in any length and can be rolled for shipping.


http://www.airpartsinc.com

PostPosted: Sat Feb 14, 2009 8:10 pm
by dmckruit
^Airparts is almost double in price not including freight. You're better off driving down to Salem, Ohio. For four sheets of 4'x10" you would save more than $200.

PostPosted: Sat Feb 14, 2009 11:23 pm
by dan galvin
I just looked you are not very far from elkart IN i found a few places
that would cut what you need from rolls if you need names and phone #
give me a email and i will send them to you
Dan :thumbsup:

PostPosted: Mon Feb 16, 2009 5:43 pm
by Rigsby
Why not try a semi trailer manufacturer for your aluminium? Thats where i bought mine from, it comes in widths of about 8`4" by what ever length you need, as it comes of the roll. In my experience it a lot cheeper too. I got a 16 length for around £50
Image

PostPosted: Tue Feb 17, 2009 1:23 am
by dan galvin
brian did you get the name & address sending e mail are weard to send here :? Dan

PostPosted: Tue Feb 17, 2009 3:22 pm
by bfitz
Dan: I did get the name. Thanks!

Rigsby: Cheap and wide would be great! I have access to $136 for 4x12, delivered to town. I'm hoping for better and especially want to find 5x.

Now, I just need to decide if I want to go all aluminum or do just the roof with woodie sides. Actually, I've been recently tempted to go all wood with the possibility of skinning in Al in the future. I know this would be more work, long-term, but I would have a useable camper this summer!
Thoughts?

-Brian

PostPosted: Tue Feb 17, 2009 7:47 pm
by bbarry
bfitz wrote:Rigsby: Cheap and wide would be great! I have access to $136 for 4x12, delivered to town. I'm hoping for better and especially want to find 5x.


$136 for 4x12 sounds like a ton of dough! What thickness is that? I found a supplier here in Wichita (granted, a airplane town with lots of aluminum) that has 4x12 .032 for $61.69/sheet and 5x12 .040 for $96.36/sheet. I don't know if they ship or what the charges would be, but here's the number: 877-265-4672.

Brad