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Re: Heavy load-bearing foamie

PostPosted: Sat Sep 23, 2017 12:43 pm
by KennethW
Just a thought. Why not have the solar panels be the roof? :thinking:

Re: Heavy load-bearing foamie

PostPosted: Sat Sep 23, 2017 5:43 pm
by John61CT
KennethW wrote:Just a thought. Why not have the solar panels be the roof? :thinking:
Not designed to be load bearing, need to be well supported, and panels aren't the only things up there.

Sealing issues.

Not insulating, and applying insulation directly would hurt both their efficiency and longevity.

But interesting thought experiment, maybe Musk's roof tiles 8-)

Re: Heavy load-bearing foamie

PostPosted: Mon Sep 25, 2017 8:49 am
by aggie79
John61CT wrote:Where I'm having more doubt is that we're not talking about static loading here, and there will be *very* large lateral and also lifting forces at play.


Agree!

Re: Heavy load-bearing foamie

PostPosted: Tue Sep 26, 2017 6:25 am
by GPW
John , you have a drawing or sketch of what you want to do exactly … or some solid clues ? If we had an idea of what you want to do , we’d be better able to come up with a few valid ideas … Apologies , I’m still confused … 8’X7’@500 PLUS pound up in the air .. is not much to go on … All I can think of now is a car carrier …

Re: Heavy load-bearing foamie

PostPosted: Tue Sep 26, 2017 6:40 am
by GPW
Seriously , look how that’s made eh . Just your Basic utility trailer ( heavy duty) , with some real sturdy frame work over the top. Something like that, you could put whatever “walls" you want on that , strap whatever on the top , and you’re good to go .
Personally ( an “opinion” ) I’d find an old car carrier trailer like this for a good price , chop it to suit carrying what we want ( were not carrying cars anymore ) , and build the DELUXE cabin on the lower , maybe a patio/cabana on top? Whatever you want . Lighter weight , a dually should handle it fine eh ? Probably got/need trailer brakes too ! Done with Foamie walls and cabin , it should be pretty light for it’s size and capacity . Hmmm? :thinking:

Re: Heavy load-bearing foamie

PostPosted: Mon Oct 02, 2017 1:23 am
by John61CT
I was starting with functionality, form will follow, so no graphic ideas.

3500 wet total weight means have to be minimal on the load-bearing, just enough for safety not over engineered like a car carrier 8-)

500 up top means not to too big a total size.

Looks like single axle way to go.

Re: Heavy load-bearing foamie

PostPosted: Mon Nov 06, 2017 7:17 am
by trfkcop
1" square tubing welded to the frame at the four corners PRIOR to foaming the walls, slip in roof rack after. Think of four "receiver hitches" on your roof to accept the rack (or racks if you didn't affix permanently)...

Re: Heavy load-bearing foamie

PostPosted: Mon Nov 06, 2017 10:57 am
by John61CT
Yes, rack must be removable for maintenance.

Re: Heavy load-bearing foamie

PostPosted: Mon Nov 06, 2017 11:32 am
by John61CT
I think the full tubing is heavier than necessary.

I'm now thinking four plain angle iron posts on the outside corners, mounted to the trailer frame.

Foamie shell for the living space enclosure, independent of the steel, but lateral dimensions sized to be "clamped" tightly by those four corner posts.

Rectangular profile tubing run along - sitting on, load partially distributed over - the top of the foamie side walls, but mostly carried by fixing to the posts at the corners.

Fixed with PlusNuts to the top of that tubing is RhinoRack or Yakima roofrack "track" for maximum flexibility, no components will touch the foam roof.

All that steel frame is as light (thin-walled) as possible, just strong enough to carry the load (yes dynamic bouncing) in the verticle dimension.

With careful sizing of both the steel frame and the foamie shell, so the former tightly grips the latter, the rigid foam acts as strong bracing to handle nearly all the lateral forces.

On second thought, maybe add some diagonal bracing at the steel frame's corners, shorter or longer depending where openings in the foamie shell are required.

The structural design of the foamie shell does not depend on any steel, the whole steel "cage" can be removed if needed for maintenance, or if the roof rack is no longer needed.

Re: Heavy load-bearing foamie

PostPosted: Mon Nov 06, 2017 11:58 am
by Pmullen503
Here's what I did with mine.

Image

Image

The corners are (2) 2"x1.5" posts tied together top and bottom with 1/2 Plywood plates glued and screwed with a foam filler strip.

To those were bolted aluminum channels for Yakima racks.

Image

Here is the build log:http://www.tnttt.com/viewtopic.php?f=55&t=61836&p=1105335#p1105335

I've carried as many as three canoes and kayaks on it at 80 mph, plenty strong.

Re: Heavy load-bearing foamie

PostPosted: Mon Nov 06, 2017 3:27 pm
by GPW
Ooh !!! Nice Rack !!! … :roll: :lol:

Re: Heavy load-bearing foamie

PostPosted: Tue Nov 14, 2017 10:58 pm
by John61CT
Pmullen503 wrote:Here's what I did with mine.

Image

Image

The corners are (2) 2"x1.5" posts tied together top and bottom with 1/2 Plywood plates glued and screwed with a foam filler strip.

To those were bolted aluminum channels for Yakima racks.

Image

Here is the build log:http://www.tnttt.com/viewtopic.php?f=55&t=61836&p=1105335#p1105335

I've carried as many as three canoes and kayaks on it at 80 mph, plenty strong.
excellent, embedding posts right in the walls is nice and clean, and wood is light vs steel.

What would you estimate max load would be on the rack?

Re: Heavy load-bearing foamie

PostPosted: Wed Nov 15, 2017 6:59 am
by Pmullen503
Hard to say, I doubt I've had more than 150 lbs. dead weight but wind loads have to be substantial. There is no evidence that it has moved after two years.

You could always add another set of bars and posts. 500lbs is a lot to put on a pair of Yakima racks.

Re: Heavy load-bearing foamie

PostPosted: Wed Nov 15, 2017 8:29 am
by John61CT
Yes, looking to put the rack tracks along the top of the sidewalls (RhinoRack lets you use either foot type) for spreading the load, adding more when needed, and general flexibility.

Now thinking back to plywood in the walls sandwich