Wood question

[kklowell]

I think I may build a pop-top truck camper for my Ranger before [font=Tahoma, Verdana, Arial, sans-serif]my next ro[/font][font=Tahoma, Verdana, Arial, sans-serif]ad trip[/font]. I've decided I'd like to be able to stand up, which I cannot do with my current setup. I'll go with a pop-top because of height when traveling concerns. Due to weight considerations, I'm thinking of using as much foam as I can in the sides and roof construction, but what I don't know is what to use for the tops of the walls. These two pieces will extend over the cab and be the main supports for the bed. I'm thinking that I could use 2x6's for the whole length from back to front so my choices seem to be cedar, pine, or a sandwich of plywood and glue. The glue-up would be strongest, but heaviest I think. Cedar would be lightest, but most expensive, correct? I think I read that it's stronger than pine though. If that's true, how about two cedar boards glued together to make my 2x6 pieces? Of course, pine 2x6 boards are relatively cheap and very available, but are they strong enough to be the support for a bed for two people who weigh a combined 430 pounds?
The base and "wings" will be plywood, and as I said, the walls and roof, 1.5" foam insulation. The whole thing would get covered in PMF, I think. I do have questions about using fiberglass though, because I may be able to get the materials at a good price at work. Is it enough stronger than PMF to be worth more? And which should be lighter?

 

[bullfrog]

Have You considered using a steel ladder rack as a frame and modifying it to fit your needs? Remember the cab moves independently of the bed quite a lot. Most truck campers built out of foam use a heavy 2x6 beam the entire length but only use that area for very light storage and do not collapse. They use the table/bed combination in most cases. It takes a lot of strength to hold 200 lbs over a span of 6' or more. Many commercial manufactured campers fail there as they age. I made mine a box and did no cab extension just for that reason. You might consider a drawer type slide out that once expanded up could slide out and rest on a rack on the cab roof. Fiberglass is stronger but much heavier and much more difficult to apply, fix and maintain.

 

[kklowell]

No, I haven't considered that... because well, I didn't know they existed.
In truth, I really doubt that bed would ever see more than me in it...my wife isn't really likely to a)get in the camper, and 2) make the climb to a bed. I'm guessing it'd have the table/bed setup as well. So, the bed would really only have a couple hundred pounds in it. Actually, now that I think about it, that would mean I could make the bed over the cab just a twin, which would mean that span would be under 4 feet. 
The weight concerns are very real, so fiberglass isn't going to happen. I need to keep this thing extremely light.

 

[bullfrog]

Harbor Freight makes a really cheap one which means thin steel and light weight. Since you are going to be closed up going down the road the base doesn't need to be very substantial and the metal frame would hold the sliding top when up. You could attach the foam for the lower portion and build a box that would fit over the bottom portion that had a drawer slide attached to top and the 4 corner posts you could use ratcheting catches or pins to keep extended maybe. Sounds like a fun project, remember wind resistance is very important if you are gonna be going over 50 MPH. Maybe you could use some discarded Easyup legs or pieces from a shade canopy for your frame.

 

[MGfromBC]

Most of my projects have been in my head so far, but there have been many of them. Here are two thoughts that seem to survive.

To go from low or travel height to high or living height, build it like a banana box. You can lift the top of the box almost to its top height and it is still fairly solid.

The second idea, as a rigid inner core for foam walls is aluminum ladders picked up on craigslist. If I were building a lift up truck camper I would set pieces of ladder along the sides of the box on the bottom section and for the long side pieces on the top part. Maybe across the roof too. For lots of insulation you could start with foam between the rungs but even if you put foam between the uprights on both sides and then more foam over the whole thing you would have a warm and solid construction.

MG

 

[kklowell]

Harbor Freight makes a really cheap one which means thin steel and light weight. Since you are going to be closed up going down the road the base doesn't need to be very substantial and the metal frame would hold the sliding top when up. You could attach the foam for the lower portion and build a box that would fit over the bottom portion that had a drawer slide attached to top and the 4 corner posts you could ese ratcheting catches or pins to keep extended maybe. Sounds like a fun project, remember wind resistance is very important if you are gonna be going over 50 MPH.

That wind resistance is a big factor in choosing the pop-up design.  If I use 2x6 lumber as the top of the wall, and make the cap about 3-4 inches thick, with a sloping front edge, the resistance shouldn't be that bad...I hope. The mechanism I'll probably use to hold the top open is something I saw in a Youtube video and is made of 3/4 EMT conduit.  It can be seen behind the guy (Tim Morrisey) is this screen capture.
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[highdesertranger]

If you are going to use dimensional lumber I would use Sitka Spruce. However plywood should work just as well. Bullfrog's idea of using a lumber rack is a very good one. Here's some pictures of lumber racks,

https://store.strongstruckaccessories.com/welulara.html

I know nothing about those racks I just grabbed the picture for reference.

Highdesertranger

 

[kklowell]

Yeah, a modified lumber rack would work, but I'll bet it's heavier than the lumber it would replace. I need this thing to be very light... a few hundred pounds at most. If it wouldn't cost a fortune, and I could weld aluminum......

 

[bullfrog]

Not the one from Harbor Freight, Lol!!! A couple of 2x6 ten foot long probably weighs more than it does check their on line catalog for the price and weight.

 

[bullfrog]

Well I just looked and they no longer offer the cheap light weight one at Harbor Freight so I would build my own. I used to try to figure out what to do to recycle EasyUp frames as I had so many and built a 6 kayak trailer out of them much lighter than wood. Light steel tubing is really very strong and something you should consider with wood still rather expensive.

 

[kklowell]

Wood sure is that! I like your idea and will look for some junk EasyUps.

 

[highdesertranger]

You want to be able to stand up in it and to be a cab over, and to only weigh a couple of hundred pounds? OK. Highdesertranger

 

[bullfrog]

You will be amazed! Get out the shrink wrap! My topper was made from 14 interior doors at 30 pounds apiece and came in at around 550 pounds. Small truck 200 pounds of tubing, 200 pounds of foam, 100 pounds of PMF. Good to go!

 

[highdesertranger]

with a cab over? Highdesertranger

 

[bullfrog]

It isn't much of a cab over, twin bed size he said.

 

[kklowell]

There's also no way that it's 200 pounds of foam according to the weights I was given for foam, which was 10 pounds a sheet. It sure wouldn't take 20 sheets to build a camper for a 6 foot truck bed.

 

[maki2]

Lumber prices can vary by location. Western Red Cedar will be less expensive to purchase near the source in Western Wa or Western Oregon. The east coast cedar varieties will cost less near where they are grown.

Sitka spruce is either going to come from Alaska or northern British Columbia. It is not going to be inexpensive to obtain.

Shipping lumber around the country adds to the cost. So try to find a local source for local lumber near where you live before you turn to purchasing from the big box stores. You could also look in the materials section of craigslist. Good bargains on leftover or 2nd hand lumber show up there.

I am currently camped in a forest of Ponderosa pine. So if I wanted to use pine I would hunt it out from a local person who mills and kiln dries it.

When doing a build like this you are not limited to getting the wood from sources that have to have it inspected and graded for selling it to the home building industry so thast it passes code inspectors who look at the structures.

Tough times, high prices mean you might consider looking for alternative locations to source the wood.

 

[kklowell]

Tough times, high prices  mean you might consider looking  for alternative locations to source the wood.

 I have a pretty complete woodworking shop so I've been buying rough-cut local lumber, but that's not kiln dried. The one or two places that kiln dry it have taken advantage of the high lumber prices at the big suppliers and are charging much more. That's all additional incentive to look at building this thing largely from insulation foam board.

 

[Spaceman Spiff]

My 2¢:

If it is just going to be you alone, ditch the cab over; it will eliminate a lot of your engineering/building problems.

Ladder/lumber racks are truck width, so you will need to sleep north-south unless you are comfortable sleeping scrunched up.

Might want to consider a hammock for sleeping, pitched diagonally.  Put it up to sleep, its out of the way the rest of the time.

I'd look at builds in Expedition Portal and some of the foamies sites to get ideas on how others have done home builds.