Building your own canopy/camper.

chilliwak

Expedition Leader
No Haven, I have had no problems with the canopy hitting the top of the cab because it sits a couple of inches above the height of the cab. The flashing that I have installed around the bottom of the section that overhangs the trucks cab is much lower than the canopy itself, giving the impression that there is much less clearance.
Dale, please keep us informed about your project with the canopy that you will build using Polyboard. I would be interested to know how much a 3/4 ply sheet costs. I look forward to hearing about your project....:ylsmoke:
 

chilliwak

Expedition Leader
Has anybody ever worked with Polyboard? Can you cut it with a circular saw/handsaw? Is it strong enough for structural applications?:costumed-smiley-007
 

Northman

Adventurer
I've build my Boxes from Multiplex , in german we call it Siebdruckplatte . It is waterproof and very strong . You can use a Handsaw/Circular Saw . :sombrero:

 

adrenaline503

Explorer
Has anybody ever worked with Polyboard? Can you cut it with a circular saw/handsaw? Is it strong enough for structural applications?:costumed-smiley-007
I have not used it, but I do know that it can be cut with regular wood working saws and blades. I believe it has very similar properties to plywood. If by structural you mean using it as a wall or ceiling with no support, I would say no. Its hardly a Nidacore type material, nor is it a structural panel. The advantages are that its waterproof and wont rot or swell. If I were to build a camper with I would buy a few 3/4" sheets and cut them into 2-3" strips and use that for framing. Attach them from the back side with a HPDE compatible glue. Fill the voids with rigid foam attached by 3M spray adhesive. If you planned it out, you could have no exterior screw holes and the entire unit would be impervious to water. Additionally the box would have similar thermal properties, always a plus. My biggest concern is weight, I haven't compared the weights to plywood so maybe its not that much of a drawback. Plus, you don't have to use any aluminum on the outside, so in the end it might be break even or be lighter. If someone wants to figure out weight by square foot between different products that would be cool.
 

Terrainist

Explorer
I have a Callen cabover on a '93 dodge that has the cabover portion clearing the top of the cab by one inch. It was a great concern of mine that it was too close. But after extensive testing (read twisting) and referencing photos on the Callen website, my concerns were gone and I bolted it down. And I just got back from twisting it loaded and had no problemos.

It's an interesting dynamic the way a truck (this truck) twists, like there is an axis right down the center of the truck front to back. The front goes left, the back goes right, and the cabover just rotates back and forth over the top of the cab always maintaining the same clearance. Sort of spooky to watch and look at, but it never comes near the cab. Just goes back and forth, left and right, like a pendulum. Not down.

And as a side note, the truck bed and cab can be shimmed accordingly to help things.
 

chilliwak

Expedition Leader
First, Northman it looks like the material that you are using is very similar to the concrete form plywood we have in Canada. Very solid stuff, but also expensive. Nice looking box you have made for your Blazer!
Secondly, Andrenaline I can totally follow your description about how you would make a box with the strips and concealed screw holes. Sounds ingenious!
Thirdly, Terrainist I have the same experience with the cabover on my truck. It seems that the box and cab articulate in opposite directions but still never come in contact with each other. Kind of a funky experience!:costumed-smiley-007
 

adrenaline503

Explorer
Okay, so this is the APPROXIAMTE break down of weight and cost of plywood vs. Polyboard.

Plywood: 4'x8'sheet weighs 25 lbs per 1/4" of thickness.
Polyboard: 4'x8'sheet weighs 36 lbs per 1/4" of thickness.

That's a 44% increase in weight for Polyboard vs. plywood.

.020" aluminum sheet weighs in at 9.6 lbs for a 4'x8' sheet, add that to the plywood and that's 34 lbs total. I imagine that glue and fasteners to secure the aluminum to the plywood would weigh in at least 2 lbs, so it looks like you break even.


Cabinet grade plywood cost:
Thickness Type Size Price

1/4" Sanded Hardwood 4x8 Sheet $18.44
1/2" Oak (3-ply) 4x8 Sheet $38.47
3/4" Oak (5-ply) 4x8 Sheet $39.95

Polyboard cost:
1/4" Polyboard 4x8 sheet $43.59
1/2" Polyboard 4x8 sheet $61.60
3/4" Polyboard 4x8 sheet $86.28

That means that for 1/4" Polyboard is 42% more, 1/2" is 62% more and 3/4" is 46% more expensive than plywood. If you used the .020" aluminum sheet at $50-70, regardless of thickness Polyboard is cheaper. If you had a cheap source of aluminum then of course it would be different, I just used Google search so I'm sure that's max price. Add in the cost of glue and fasteners to attach the aluminum and the gap opens further.

According to my calculations Polyboard weighs about the same as plywood and aluminum and may be cheaper depending on your sources.

Now that I look at this again, the thicker you go with Polyboard the heavier it is. A 3/4" Polyboard weighs 98 lbs where as plywood comes in at 75lbs. Add the 10 lbs for the aluminum and the 3/4" plywood/aluminum combo weighs 85 lbs. So 10 lbs more per 4'x8' area.

If I were to use Polyboard I would definitely use 1/4" for the outside, ribs out of 2" 3/4" strips with a rigid foam void filler. Bond all the seams with a HPDE adhesive and I think you would be water tight. I would sheet the inside with varnished 1/4" plywood, its light and looks nice. Now, if I can figure out how to make a pop top light enough to be supported by the Polyboard foam panels I'll be in business.
 

Dale

Adventurer
Okay, so this is the APPROXIAMTE break down of weight and cost of plywood vs. Polyboard.

Plywood: 4'x8'sheet weighs 25 lbs per 1/4" of thickness.
Polyboard: 4'x8'sheet weighs 36 lbs per 1/4" of thickness.

That’s a 44% increase in weight for Polyboard vs. plywood.

.020" aluminum sheet weighs in at 9.6 lbs for a 4'x8' sheet, add that to the plywood and that’s 34 lbs total. I imagine that glue and fasteners to secure the aluminum to the plywood would weigh in at least 2 lbs, so it looks like you break even.


Cabinet grade plywood cost:
Thickness Type Size Price

1/4" Sanded Hardwood 4x8 Sheet $18.44
1/2" Oak (3-ply) 4x8 Sheet $38.47
3/4" Oak (5-ply) 4x8 Sheet $39.95

Polyboard cost:
1/4" Polyboard 4x8 sheet $43.59
1/2" Polyboard 4x8 sheet $61.60
3/4" Polyboard 4x8 sheet $86.28

That means that for 1/4" Polyboard is 42% more, 1/2" is 62% more and 3/4" is 46% more expensive than plywood. If you used the .020" aluminum sheet at $50-70, regardless of thickness Polyboard is cheaper. If you had a cheap source of aluminum then of course it would be different, I just used Google search so I'm sure that’s max price. Add in the cost of glue and fasteners to attach the aluminum and the gap opens further.

According to my calculations Polyboard weighs about the same as plywood and aluminum and may be cheaper depending on your sources.

Now that I look at this again, the thicker you go with Polyboard the heavier it is. A 3/4" Polyboard weighs 98 lbs where as plywood comes in at 75lbs. Add the 10 lbs for the aluminum and the 3/4" plywood/aluminum combo weighs 85 lbs. So 10 lbs more per 4'x8' area.

If I were to use Polyboard I would definitely use 1/4" for the outside, ribs out of 2" 3/4" strips with a rigid foam void filler. Bond all the seams with a HPDE adhesive and I think you would be water tight. I would sheet the inside with varnished 1/4" plywood, its light and looks nice. Now, if I can figure out how to make a pop top light enough to be supported by the Polyboard foam panels I'll be in business.
Did you happen to find any specs on the Nyloboard I originally talked about?
 

chilliwak

Expedition Leader
I've build my Boxes from Multiplex , in german we call it Siebdruckplatte . It is waterproof and very strong . You can use a Handsaw/Circular Saw . :sombrero:

I really like the look of those boxes you have built Northman!:victory:
 

chilliwak

Expedition Leader
This is what we will be wheeling in about 2 weeks time......:Wow1:

Its going to be fun!:wings::truck::campfire::steak::beer::safari-rig:
 
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