After much inter web surfing I decided to build a cab over. It will be going on a 2004 Ram 2500 diesel 4x4 short bed. I started building the frame out of1x1 square tubing. Outside will be covered with .040 aluminium, insulation one inch foam, and inside with quarter inch ply. The cab over portion will be four foot over the cab. Still deciding if I want to go six or eight foot in the bed. From the top of the camper to the ground is right at 10 feet. It is going to start out basic and add to it as I go. I'll post pics as I go. I'm open to advice.
Building an elk hunting rig
- Thread starter Jkrpan
- Start date
boxcar1
boxcar1
Use 1x2" x .065 for the roof and cab over floor. This will allow for twice the insulation in those critical arias as well as double the strength of the chassis.
![unnamed[6].jpg](https://expeditionportal.com/forum/data/attachments/247/247713-39acc101aa526808627a4e6669e6482e.jpg "unnamed[6].jpg")
The chassis pictured is an 8 footer with a 60" overhang ( bunk ) that will work in a short or long bed. Chassis weight is 320lbs.
The chassis pictured is an 8 footer with a 60" overhang ( bunk ) that will work in a short or long bed. Chassis weight is 320lbs.
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boxcar1
boxcar1
The inner panels were all shot with flush tech screws.
I used these where they don't show.
Where the screws show I used a button head Tech screw in a polished finish. Same brand.
Sorry , no close up of those screws. But if you look hard enough you can see them in this picture.
All available at Home despot.
I used these where they don't show.
Where the screws show I used a button head Tech screw in a polished finish. Same brand.
Sorry , no close up of those screws. But if you look hard enough you can see them in this picture.
All available at Home despot.
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Scoutn79
Adventurer
What about using something less thermally conductive than aluminum for the skin? Fiberglass composite? We Elk hunt in an aluminum framed and skinned travel trailer with 2" thick walls and 4" ceiling.
At-10F you can see frost build up on the wood interior panels where the framing is. At -25F you really notice it. We keep the camper at 50-55F at night.
I wonder how much difference a different skin might make. At those temps I think anything would help.
Darrell
At-10F you can see frost build up on the wood interior panels where the framing is. At -25F you really notice it. We keep the camper at 50-55F at night.
I wonder how much difference a different skin might make. At those temps I think anything would help.
Darrell
boxcar1
boxcar1
Yes . Fiberglass panels would work just as well as aluminum ( if not better in some circumstances.) But neither of us are using aluminum chassis.
The seam sealer tape I used on mine acts as a thermal break between the skin and steel chassis.
I chose the aluminum for the look, ease of use, cost and reparability in the field.
I will admit that I looked hard at glass panels before I chose to use aluminum.
The seam sealer tape I used on mine acts as a thermal break between the skin and steel chassis.
I chose the aluminum for the look, ease of use, cost and reparability in the field.
I will admit that I looked hard at glass panels before I chose to use aluminum.
IdaSHO
IDACAMPER
The skin alone will make very little difference.
Regardless of skin, the frame is still basically un-insulated from the exterior, so the framing will still get cold.
The only way to get around the condensation on the interior of such a frame is to install thermal breaks or barriers of some sort.
Fastening the skins inside and out right to the frame is not the way to do it if you are worried about the severe cold and the problems associated with it.
FYI, the thermal conductivity of most aluminum is roughly 400% greater than steel (mild)
And the thermal conductivity of steel (mild) is 500%+ greater than wood.
boxcar1
boxcar1
As posted by Wikipedia on there thermal conductivity chart:
Fiberglass =0.045
Wood ( fir ) in an absolutely dry state = 0.04
At 15% moisture content ( normal )= .117
Steel = 36.0
Aluminum = 204.3
As I stated before with a thermal break of some kind None of this information really matters. But it is interesting.
While wood is a pretty good insulator, it has poor structure to weight ratios compared to steel, aluminum or composites. Not to mention the dry rotting issues wood constructed chassis suffer.
Using wood as an outer skin is a real problem. Heavy to begin with, now add fiberglass over the wood skin and it becomes one of the heavier materials one could choose.
At some point one has to compromise when constructing a 4 season rv. But if you take the time to figure out the deficiencies and attributes that all materials have , few problems are insolvable .
Fiberglass =0.045
Wood ( fir ) in an absolutely dry state = 0.04
At 15% moisture content ( normal )= .117
Steel = 36.0
Aluminum = 204.3
As I stated before with a thermal break of some kind None of this information really matters. But it is interesting.
While wood is a pretty good insulator, it has poor structure to weight ratios compared to steel, aluminum or composites. Not to mention the dry rotting issues wood constructed chassis suffer.
Using wood as an outer skin is a real problem. Heavy to begin with, now add fiberglass over the wood skin and it becomes one of the heavier materials one could choose.
At some point one has to compromise when constructing a 4 season rv. But if you take the time to figure out the deficiencies and attributes that all materials have , few problems are insolvable .
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Scoutn79
Adventurer
Interesting that steel transfers heat 80% more efficiently than aluminum...I can't say I believe that...surely not on Wikapedia.
Your comments on wood are the exact reason we use an aluminum framed trailer, It does conduct heat very well, or bad depending on how you look at it, but it light weight, easier to repair, stronger, better vibration resistance, structurally more rigid no rot than wood framed trailers.
I wasn't suggesting using FRP panels over wood exterior but a fiberglass/composite skin alone. The aluminum skin will still pull what little heat transfers through the insulation, and it will transfer, and with that much sq ft it will make a difference in how easy it is to keep the camper at a comfortable temperature. Especially if you are only going with 1" of insulation.
The thermal breaks are just part of the total equation.
When you are sitting in a camper 60 miles form the nearest town and it is -25 f you tend to notice little things. We do sit around and try to figure out what we would change if we designed a 4 season camper.
I guess it really comes down to the weather you expect to encounter in the season you hunt. Early November in Colorado can get cooold.
Instead of blue board what about finding a company that sprays expanding insulation and have them shoot it once skinned....if you take to to a jobsite they may do it for cheaper since the equipment is already set up.
Just some thoughts
Darrell