Sleeping on the roof

[mvankanan]

I got the headliner out, I was a little bummed out because the cross ribs were in the way of my holes in the roof. I went and saw my car guy he said mike think about any van conversion when the take the whole roof off, where are the cross pieces? So now I’m a whole lot less worried and I’m going to just go for it. Bad weather for the next week it looks like; wish I had a big shop with a level floor.

As far as not worried about cutting into the roof, this frees up the design a bit, if I can move the entrance hole back, with a drop in panel to sleep on, I think I can change the build profile and lower the front height, and angle. I’ve been playing around with crawling in and out of the mock up with different heights, if the hole is larger I can get by with less height, at least in the feet end. Maybe a pop up part over my head?

It occurred to me that it might be a lot easier to bend tubing to fit the roof profile, I could then screw or bolt some plywood strips connected to the sides of the floor panel to the tubing, and the tubing to the roof. This might make it a lot easier to level. I wouldn’t have to be as accurate cutting the bottom of the ply strips, I could then wrap the canvas under the whole floor, and then set it back on the tubing and attach it. The problem would be in getting some kind of gasket for the tubing? Something like that slip on foam pipe insulation comes to mind but that wouldn’t be rugged enough. Anyone have any ideas for the gasket?

I’m thinking emt conduit for the tubing. More weight then I want, but that seems easier to fabricate? It would need to be u shaped two sides and the front, maybe one and a half inches so I will have more meat to attach the build?

I guess I will use titebond 2 to make the floor panel, 1” foam 1/8 luan top and bottom, wood around the edges to bolt thru. I’m planning to leave it solid and cut out the holes for the skylight and entrance later, I’m thinking I could cut the holes and then rout out the foam, leaving the ply and then glue in the wood strips around the edges of the holes?

Whatever I use for the wood edges presents a bit of a problem because the foam is a full inch, wood is only ¾” seems like I might want it a little wider for bolts? 5/4 on the flat is still only 7/8”? I’m thinking of gluing 1x3 together on the flat and then resawing that to get the full inch I need, I’ll end up with a 1 ½” x 1” piece. I guess I could try to find ¾” foam but I would rather have thicker, without the height constraints I would prefer 2”. I feel like I’m limited by what’s at Home depot 1” or 2” in full 4x8 square edge. Don’t want to get it shipped or special order for fear of damage to the edges and it’s only one sheet for the floor?

Getting the floor up on the roof should allow me to visualize what I’ll have to work with better as far as height. I have another wrinkle in that the jeeps a little wider below the roof in the back so once I get the floor up there I can get an idea of what I can do there. It is tempting to make the whole build a little wider than the roof but then I’m dealing with lift? Anyone with the engineering skills to puzzle me through that? It would be about 3-4” on each side? That might cause me to need more foam for the roof but then again I could angle that, say the bottom is 56” the top could still be 48”?

Thanks Mike

MIke,
Van conversions are built on a truck frame, the later model cherokees and grand cherokees are unibody contruction. The roof member are part of the frame that holds the whole thing together. If you cut those out, you need to install something to take their place, like a well built roll cage that ties into the chasis with strong connections.
Tom

Thanks Tom

Is a 93 a late model? The cross pieces aren't welded to the roof but glued or stuck with something that looks like bituthene tape. They are only welded at the sides, and only spot welded in a couple of places. Not sure how that works, the ribs aren't much thicker metal than the roof it's self, they are formed, but they’re only about ½” thick, not the metal but the whole profile, they have three ribs across but only two at the ends where the meet the side frame. They are 5” wide. I was surprised that they don’t connect to the door post? I would have thought that’s were all the strength would be, and that would transfer the force down to the chasis? My first thoughts were to get some channel and run that across the roof at both the front and the rear door post, and then frame the hole to them?

In all fairness to my car guy he said Mike do what you want and bring it back and I’ll make it work. I’ll probably let him build the tire rack I want to install on the back.

Thanks for getting back to me, I'm anxious to get going but I'm not going to cut anything yet.

[Socal Tom]

Is a 93 a late model? The cross pieces aren't welded to the roof but glued or stuck with something that looks like bituthene tape. They are only welded at the sides, and only spot welded in a couple of places. Not sure how that works, the ribs aren't much thicker metal than the roof it's self, they are formed, but they’re only about ½” thick, not the metal but the whole profile, they have three ribs across but only two at the ends where the meet the side frame. They are 5” wide. I was surprised that they don’t connect to the door post? I would have thought that’s were all the strength would be, and that would transfer the force down to the chasis? My first thoughts were to get some channel and run that across the roof at both the front and the rear door post, and then frame the hole to them?

In all fairness to my car guy he said Mike do what you want and bring it back and I’ll make it work. I’ll probably let him build the tire rack I want to install on the back.

Thanks for getting back to me, I'm anxious to get going but I'm not going to cut anything yet

The thing about unibody is that they spread the load over a bunch of lightweight stuff to save weight. So just because those roof spars are light weight doesn't mean you can discount them, but it does mean that if you loose one, its probably not a big deal. I feel better knowing your "car guys" will patch things together once you get it done. I would still be cautious about cutting too many of those spars.
Tom

[mvankanan]

Interested in development here, also want to do something rooftoppy, more leaning to tents though.

Some thoughts...

In Dodge vans which are also unibody, what I've seen done is that the pressed roof "ribs", were carefully cut off the area where the roof penetration was, and move forwards and backwards and rewelded. This may or may not be a suitable approach on the Cherokee.

Mike
I thought of this, they fit into a kind of cutout so it might not be so easy, as I said to Tom I thought of a piece of channel across the door post, my thoughts were to beef it up, the door posts seem thicker, there is also a big bolt that holds the seat belts that I could use


Another thought is to look at the structural differences between the original XJ Cherokee and the Commanche pickups.

Sometimes manufactures publish or have available by special request vehicle modifier guides, that show the hardpoints and the "do not cut, really, ever" points on the structure to assist in police and ambulance conversions and other special uses. It seems to me I might have seen a mountain rescue Cherokee with raised top in the past. Also try looking for wheelchair conversions, may have been done for people in rural 4x4 required areas.

Mike
I'd like to do this but I can't seem to find anything on the internet?


Also with this, Chrysler's unibody thinking still had a lot of body on frame thinking going on, many of them practically have a frame, it's just a layer of metal short, the floorpan capping the U section instead of box section then floorpan.

Mike
not sure exactly what you mean? it does seem that the structure along the sides is where all the strength is, seem pretty robust?

It's not quite a case of fall apart as soon as it's got one hole in it, but caution still advised in modification. Another clue, round holes where possible, well radiused corners where you want something squareish. Spreads stress.

Mike
Yeah I'll do that.

For the floor, 3/4 needed if it's going to be on a couple of roof bars, and all the weight on those... if you're spreading the weight thoroughly, then you can go down to half inch, maybe even lower if it's full foam contact to profile of roof.

Mike
I just climbed up on the roof, I would have caved in the Suby doing that. There are ribs that run front to back, it seems strong? I'm not sure I see the need for 3/4 ply to spread the weight? If you think of it like a hollow core door as long as you don't puncture the luan they don't seem to flex any more than 3/4 ply would? and it will be filled with foam and canvas on top? I will try to contact the roof over the whole surface as much as possible I do think that high quality 3/4 ply would do a lot to strengthen the whole build and tie it all together

A clue on how that might be achieved... fill a huge bag with 2 part foam, spread on roof, squish floor down on top of it, let set, remove bag, trim it up and you've got perfect fit to roof. This foam kind of dense, might want to rough profile in styrofoam under you floor board, so you only need a thin layer of this.

Mike
maybe lay some plastic under the floor before installation, drill a couple of rows of smallish holes and use some of that one part foam, the low expansion kind, cut off any over flow and then put down the interior canvas? Anyway seems that this might be better then trying to shim it some how.

Other things to look at for inspiration, Saab and Prius drop in campers, they're the tailgate removal cabover
type.

I'll check these out.

Thanks Mike

[mvankanan]

Hi again can you glue Fiberglass reinforced plastic (FRP) to wood, and canvas? The return down to the bumper is a bit more complicated, I thought it would be but I was hoping it would be less so.

Thanks Mike

[mvankanan]

Hi

I logged in and wrote a comment and when I went to submit it I was logged out, my fault should have done it on word, as I’m now doing, but why does it do it? Is that comment somewhere? I’m a real slow typer, is there a way to extend the time out? I just keep thinking oh a couple of quick questions.

Anyway here goes again. I’m doing another mockup, I can’t figure out how to tie the roof to the hatch because of the shape of the hatch. My new design has the floor of the sleeping chamber 56” wide; I’m then slopping the walls of the sleeping chamber so that the roof is a little less than 4’, about a 10 degree angle. Can I use wily windows in those sloped walls?

About working with great stuff, what does folding mean? What kind of working time do you get with that? Is that what you use to fill kerfs?
I’ll probably kerf the back hatch for strength, it will be about 4’ wide and 5.5’ high, and that seems too big to be flat? Should I also have sides on the hatch for more strength?

I should have some pictures up in a couple of days.

Thanks mike

[wagondude]

Hi

I logged in and wrote a comment and when I went to submit it I was logged out, my fault should have done it on word, as I’m now doing, but why does it do it? Is that comment somewhere? I’m a real slow typer, is there a way to extend the time out? I just keep thinking oh a couple of quick questions.

When you log in, check the box that says "log me in automatically". That will keep you from getting bumped out every few minutes.

[mvankanan]

Hi all

I picked up my foam last night, I got it from Home depot. I decided to go with all 2" including the floor. I had trouble finding any other. All the sheets are deformed on one edge, they are thicker,they kind of bell out. I bought a sureform planer to try to flatten them, so I can glue them better. Anyone else encounter this with foam? I looked through both lifts, and they where all like that?

No pictures yet, I have to get some kind of platform up to do a proper mock up, and get the final dimension. I'm firming up the design, I'm going to try to mount the spares one on each side of the rear of the build, think it might work.

So Gorilla glue for the foam to 1/8 luan? Is this the best way to go it's a bit pricey?

To get my roof curve, I'm planning on trying to straighten some of the soft copper tubing, bend it to shape, secure it with blocks to prevent it from moving, and use it as a guide for a roller on a router bit. Hope it works, Trying to mark and cut wood directly was a pain last year on the Suby. Anyone have a better idea?

Had to build a 6'x12'x4' high table in my drive way, pretty depressing trying to find anything straight to use. I ripped some 2x4 to use for the mockup, they just went every which a way on me.

I know no pictures it ain't happening but they are coming.

Mike

[ghcoe]

Hi all

I picked up my foam last night, I got it from Home depot. I decided to go with all 2" including the floor. I had trouble finding any other. All the sheets are deformed on one edge, they are thicker,they kind of bell out. I bought a sureform planer to try to flatten them, so I can glue them better. Anyone else encounter this with foam? I looked through both lifts, and they where all like that? Some of mine where cupped slightly. I really did not worry about it. The foam is really inconsistent in thickness through out the sheets. You will find that one side will angle down to the edge while being flat on the other. I did not realize this till I had already cut my walls. A sanding block will probably work better than the planer. Foam cuts real fast with a sanding block.


So Gorilla glue for the foam to 1/8 luan? Is this the best way to go it's a bit pricey? I have had good luck with Dap caulking for glue ups lately. Oddly though I have not tried the wood to foam test yet, but it could be a option.

To get my roof curve, I'm planning on trying to straighten some of the soft copper tubing, bend it to shape, secure it with blocks to prevent it from moving, and use it as a guide for a roller on a router bit. Hope it works, Trying to mark and cut wood directly was a pain last year on the Suby. Anyone have a better idea? I would use hardboard for a template. Usually about $8.00 a sheet. Then you can draw out the shape you want on it and cut it out with a jig saw. Sand the edges smooth and you have a template. Finding a router bit over 2" long is going to be rough though.

Mike

[mvankanan]

Hi all

I picked up my foam last night, I got it from Home depot. I decided to go with all 2" including the floor. I had trouble finding any other. All the sheets are deformed on one edge, they are thicker,they kind of bell out. I bought a sureform planer to try to flatten them, so I can glue them better. Anyone else encounter this with foam? I looked through both lifts, and they where all like that? Some of mine where cupped slightly. I really did not worry about it. The foam is really inconsistent in thickness through out the sheets. You will find that one side will angle down to the edge while being flat on the other. I did not realize this till I had already cut my walls. A sanding block will probably work better than the planer. Foam cuts real fast with a sanding block. I happened to be in Lowes today, they sell the green foam, mines pink, the green seems to more consistent, but there is a raised border around the whole sheet on both sides, it's about 2" wide and maybe a 1/32" difference? Seems like a better product, not sure it's worth loading up my stuff and taking it back? I'll try the sand paper, I should be able to use a half sheet on a board to help me get it flat, kind of like an old jointer plane, or a darby for concrete.


So Gorilla glue for the foam to 1/8 luan? Is this the best way to go it's a bit pricey? I have had good luck with Dap caulking for glue ups lately. Oddly though I have not tried the wood to foam test yet, but it could be a option. Is this just the acrylic latex calk? What do you use it for foam to foam? edge bonding?

In general do folks cover the whole surface with adheasieve when gluing ply to foam, or just lay out beads?

To get my roof curve, I'm planning on trying to straighten some of the soft copper tubing, bend it to shape, secure it with blocks to prevent it from moving, and use it as a guide for a roller on a router bit. Hope it works, Trying to mark and cut wood directly was a pain last year on the Suby. Anyone have a better idea? I would use hardboard for a template. Usually about $8.00 a sheet. Then you can draw out the shape you want on it and cut it out with a jig saw. Sand the edges smooth and you have a template. Finding a router bit over 2" long is going to be rough though. The problem with that is being able to hold the hardboard to mark it. I tried all kinds of ways last year, had about 100 lbs of weights on the car and a bunch of tape, it was still moving around, plus just like now with trying to do the mock up there's no reference point. no square, level, plumb. I think with the tubing I can tape it along the line I want and then press it down, at least I hope too. I wont need a 2" router bit, I'll be cutting four pieces of 1by, two for each side. I'll then glue them together and they will be glued to the underside of the floor, back from the edge, they will catch the gasket that seanc used and the whole thing will be through bolted to the jeep. The whole build will be off the jeep along each side to address another problem. Pictures coming

Thanks for the input. Mike



Mike

[ghcoe]

So Gorilla glue for the foam to 1/8 luan? Is this the best way to go it's a bit pricey? I have had good luck with Dap caulking for glue ups lately. Oddly though I have not tried the wood to foam test yet, but it could be a option. Is this just the acrylic latex calk? Yes.What do you use it for foam to foam? edge bonding?I have been using it to glue flashing to foam edges and did a test foam to foam. I found it much easier to use than the foaming glues and seems to bond just as well. Takes longer to dry thoroughly though.

To get my roof curve, I'm planning on trying to straighten some of the soft copper tubing, bend it to shape, secure it with blocks to prevent it from moving, and use it as a guide for a roller on a router bit. Hope it works, Trying to mark and cut wood directly was a pain last year on the Suby. Anyone have a better idea? I would use hardboard for a template. Usually about $8.00 a sheet. Then you can draw out the shape you want on it and cut it out with a jig saw. Sand the edges smooth and you have a template. Finding a router bit over 2" long is going to be rough though. The problem with that is being able to hold the hardboard to mark it. I tried all kinds of ways last year, had about 100 lbs of weights on the car and a bunch of tape, it was still moving around, plus just like now with trying to do the mock up there's no reference point. no square, level, plumb. I think with the tubing I can tape it along the line I want and then press it down, at least I hope too. I wont need a 2" router bit, I'll be cutting four pieces of 1by, two for each side. I'll then glue them together and they will be glued to the underside of the floor, back from the edge, they will catch the gasket that seanc used and the whole thing will be through bolted to the jeep. The whole build will be off the jeep along each side to address another problem. Pictures coming Guess I missed what the question was here. Thought you were trying to shape foam

Mike