I saw someone else mention in another thread they did angle brackets and rivets to join together their frame.
I have no personal experience or input on it.
Contemplating building my own camper
- Thread starter IHDiesel73L
- Start date
I saw someone else mention in another thread they did angle brackets and rivets to join together their frame.
I have no personal experience or input on it.
Looks like you're path is getting a bit more parrallel to mine, you're just subbing out some of the fiberglass plys for wood plys.
Offhand I'd be shocked if you'd need metal framing in the cabover if you're doing 2" foam sheathed in plywood and then fiberglass. Since this is a hardside camper and not a pop-up (which I'm doing and it makes things more complicated) your cabover is now just a big box tube. If you make your panels well and tie them together well it should be fine. When you're serious on a build a calc could be ran to verify everything, worst case you'd need a little more fiberglass on the outside.
Here's my long winded take on things.
If it was me doing your design here's how I'd build panels:
1.) Since you're doing 2" thick foam try and track down some of the 60psi compression strength stuff, from my pricing its only a buck or so more on a 2'x8' sheet.
2.) Buy your foam in 2'x8' sheets, its usually more readily available, will be easier to handle and will work out for point three.
3.) Third to really make sure your skins are tied together rock solid (thats how this type of structure needs to work) I'd add in plywood strips the thickness of the foam between the two plywood skins. Strips that are 2' apart running the long span of the camper design would likely be adequate, doing a 2'x2' grid would be even more robust. 2' also conveniently fits the standard panel width. [Note these next steps can be done in stages, not all at once] Use thickened epoxy (epoxy and wood flour would be good) and glue these and any other wood blocking you've deemed necessary to one side of the skin, narrow crown stable from the other side of the skin to pull it all together while the epoxy sets. Then cut all your foam pieces to fit the spaces, rough them up with ~50grit sandpaper. Coat the plywood skin and wood strips with plain epoxy, coat the foam with a mirco slurry (1 part epoxy, 1 part micro balloons) and push them into place. Ideally these should have been friction fit but if there are gaps fill them in with micro (ideally a even thicker mixture of epoxy and micro balloons). Then coat the foam side of the other skin with plain epoxy and lay it over top of the panel (a bit of thickened epoxy over the wood strips would be good too), narrow crown stable it along the wood strips to snug it all together while it cures.
3.a.) The above just rushed ahead and completed a side of the camper assuming you had it all figured out, in reality you'll probably be doing a bit of thinking on the fly. So I'd say do the outer skin, attach the wood striping, glue in as much of the foam as you think you definitely won't need to mess with and friction fit the rest for now. Then put your camper together, have wood blocking on the edges to screw things together temporarily. Just lay a sheet of wood over the walking surfaces inside so you don't beat up the foam for now. Figure out any interior features that would require structural backing, etc. and cut out foam appropriately to fit the backing in. If you want to bury the electrical conduits router those in, etc. Then when all that is done pull it back apart, bond in the rest of the foam and any new blocking, etc. and then finish the other skin.
4.) Now that you have rock solid panels fiberglass the outer surfaces of them in the horizontal, it'll be much easier. Then when all pieces are done you put them together by first applying thickened epoxy between the panels (if you did the 3.a. step use those same screw blocks to hold things while the epoxy cures). Use thickened epoxy to fillet all the inside corners. Then use fiberglass strips (with the fibers on +/- 45deg to the joint) on each side of the joint to lock it all together.
5.) Fair the surfaces, prime and paint.
Obviously that was a really high over view but gives the general idea.
Offhand I'd be shocked if you'd need metal framing in the cabover if you're doing 2" foam sheathed in plywood and then fiberglass. Since this is a hardside camper and not a pop-up (which I'm doing and it makes things more complicated) your cabover is now just a big box tube. If you make your panels well and tie them together well it should be fine. When you're serious on a build a calc could be ran to verify everything, worst case you'd need a little more fiberglass on the outside.
Here's my long winded take on things.
If it was me doing your design here's how I'd build panels:
1.) Since you're doing 2" thick foam try and track down some of the 60psi compression strength stuff, from my pricing its only a buck or so more on a 2'x8' sheet.
2.) Buy your foam in 2'x8' sheets, its usually more readily available, will be easier to handle and will work out for point three.
3.) Third to really make sure your skins are tied together rock solid (thats how this type of structure needs to work) I'd add in plywood strips the thickness of the foam between the two plywood skins. Strips that are 2' apart running the long span of the camper design would likely be adequate, doing a 2'x2' grid would be even more robust. 2' also conveniently fits the standard panel width. [Note these next steps can be done in stages, not all at once] Use thickened epoxy (epoxy and wood flour would be good) and glue these and any other wood blocking you've deemed necessary to one side of the skin, narrow crown stable from the other side of the skin to pull it all together while the epoxy sets. Then cut all your foam pieces to fit the spaces, rough them up with ~50grit sandpaper. Coat the plywood skin and wood strips with plain epoxy, coat the foam with a mirco slurry (1 part epoxy, 1 part micro balloons) and push them into place. Ideally these should have been friction fit but if there are gaps fill them in with micro (ideally a even thicker mixture of epoxy and micro balloons). Then coat the foam side of the other skin with plain epoxy and lay it over top of the panel (a bit of thickened epoxy over the wood strips would be good too), narrow crown stable it along the wood strips to snug it all together while it cures.
3.a.) The above just rushed ahead and completed a side of the camper assuming you had it all figured out, in reality you'll probably be doing a bit of thinking on the fly. So I'd say do the outer skin, attach the wood striping, glue in as much of the foam as you think you definitely won't need to mess with and friction fit the rest for now. Then put your camper together, have wood blocking on the edges to screw things together temporarily. Just lay a sheet of wood over the walking surfaces inside so you don't beat up the foam for now. Figure out any interior features that would require structural backing, etc. and cut out foam appropriately to fit the backing in. If you want to bury the electrical conduits router those in, etc. Then when all that is done pull it back apart, bond in the rest of the foam and any new blocking, etc. and then finish the other skin.
4.) Now that you have rock solid panels fiberglass the outer surfaces of them in the horizontal, it'll be much easier. Then when all pieces are done you put them together by first applying thickened epoxy between the panels (if you did the 3.a. step use those same screw blocks to hold things while the epoxy cures). Use thickened epoxy to fillet all the inside corners. Then use fiberglass strips (with the fibers on +/- 45deg to the joint) on each side of the joint to lock it all together.
5.) Fair the surfaces, prime and paint.
Obviously that was a really high over view but gives the general idea.
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What is the weight and insulation properties of a sheet?
That is the big draw to me for the foam core stuff, really light and built in insulation. If we're throwing those two on the window then plywood is pretty hard to beat for low cost with structural properties.
foamcore panel link
http://www.portafab.com/sandwich_panels/standard.html
http://www.portafab.com/sandwich_panels/standard.html
Oneyed,
I used 1/8 in. thick x 1 1/2 in. wide x 1 1/2 aluminum angle brackets to fasten my aluminum framing together. I used 3/16 in. alum. pop rivets, 3 in each leg of the angle bracket. At high stress points like an outside corner I use 1/4 in. pop rivets and a 3 in. piece of angle. Google Cruiser Fifth Wheel Construction Details. This company builds their frames the same way except they use screws instead of pop rivets. I have a few pics in this forum. Search 2005 f150 exploration build help. There on page 3. My unit will stand on three jacks with no distortion in the frame. My tie downs are solid to the truck frame. I've been run off the road, in and back out of the ditch at around 50 mph. The frame stayed square. I was the only thing bent out of shape after coming to a stop.
Happy building.
Tom
I used 1/8 in. thick x 1 1/2 in. wide x 1 1/2 aluminum angle brackets to fasten my aluminum framing together. I used 3/16 in. alum. pop rivets, 3 in each leg of the angle bracket. At high stress points like an outside corner I use 1/4 in. pop rivets and a 3 in. piece of angle. Google Cruiser Fifth Wheel Construction Details. This company builds their frames the same way except they use screws instead of pop rivets. I have a few pics in this forum. Search 2005 f150 exploration build help. There on page 3. My unit will stand on three jacks with no distortion in the frame. My tie downs are solid to the truck frame. I've been run off the road, in and back out of the ditch at around 50 mph. The frame stayed square. I was the only thing bent out of shape after coming to a stop.
Happy building.
Tom
Tom,
A few days ago when I first read your mention of pop riveting the aluminum tube together, I thought you found some special fitting. I finally did figure out you meant angle brackets similar to
http://www.mcmaster.com/#angle-brackets/=azthvl but made of of aluminum.
and the size you mention.
I just looked at the 5th wheel construction you mentioned
http://www.crossroadsrv.com/cruiser/construction.pdf
I can see a joint like that would have very strong resistance to bending and would not question your test that it was stronger than the weld.
To me your framing method is something to consider.
Thank you
A few days ago when I first read your mention of pop riveting the aluminum tube together, I thought you found some special fitting. I finally did figure out you meant angle brackets similar to
http://www.mcmaster.com/#angle-brackets/=azthvl but made of of aluminum.
and the size you mention.
I just looked at the 5th wheel construction you mentioned
http://www.crossroadsrv.com/cruiser/construction.pdf
I can see a joint like that would have very strong resistance to bending and would not question your test that it was stronger than the weld.
To me your framing method is something to consider.
Thank you
oneeyedjackass
New member
Just a thought...
I would like to do most of the build in the garage. What about building wall panels separately, flat on a floor then assemble and bond corners when all are ready? Also, what about using regular old smooth hard side fiberglass rv siding layed flat (upside dw) and bond 1"& 2" foam and structural members as required for design? I'm not sure if fiberglass siding is raw on one side, not sure how well you could bond foam to a smooth surface.
I would like to do most of the build in the garage. What about building wall panels separately, flat on a floor then assemble and bond corners when all are ready? Also, what about using regular old smooth hard side fiberglass rv siding layed flat (upside dw) and bond 1"& 2" foam and structural members as required for design? I'm not sure if fiberglass siding is raw on one side, not sure how well you could bond foam to a smooth surface.
Oneeyed,
There are adhesive foams in a spray can. I used it to bond the rigid foam insulation to the outside and inside skin and framing. You might want to check out 3M site. They make a tape,VHB, very high bond, specially for bonding skins to semi trailers, trucks, etc. There is a training video and online instruction at the 3M site open to the public. When I called their tech line they were very helpful. One reason I did not use it is because it's becomes one to what ever it's stuck too.The tech guy told me it was made to actually replace screws and rivets. the only ways to remove it is with an air chisel or a special saws-all blade the 3M has.
Tom
There are adhesive foams in a spray can. I used it to bond the rigid foam insulation to the outside and inside skin and framing. You might want to check out 3M site. They make a tape,VHB, very high bond, specially for bonding skins to semi trailers, trucks, etc. There is a training video and online instruction at the 3M site open to the public. When I called their tech line they were very helpful. One reason I did not use it is because it's becomes one to what ever it's stuck too.The tech guy told me it was made to actually replace screws and rivets. the only ways to remove it is with an air chisel or a special saws-all blade the 3M has.
Tom
That is basically what I was getting at, then test assembling to verify everything and drop it back apart to finish up the panels before final assembly.
The only thing I'd be concerned about on fiberglass panels is they are likely made mostly from chopped strand which is heavy and not nearly as strong as fabric. So you'd likely be adding a bunch of weight verse laying up your own glass.
Greg
Thanks for your comment. It was good to hear coming from a mechanical engineer. I'm not an engineer and was hoping for the best with my build. I realize late into to the build that I over built(unnecessary weight). I'm considering trying it again with alum. channel. Kind of like steel framing in the construction industry.
Thanks again, I can sleep better now! Tom
VicHanson
Adventurer
Just saw this and thought I would comment. I had considered building a camper from scratch and after drawing lots of plans decided to go with a 1990 Shadow Cruiser truck camper instead. I wanted to put in new insulation and add storage compartment and a motorcycle garage as I was putting it on a flat bed on an Isuzu NPR. It turned out that there was a lot of wood rot so ended up practically rebuilding the whole thing. Anyway, lots of pics on my build thread which will give you some idea of how they are built and the mods I did. It had thin plywood on the inside, 1x2 frame with fiberglass batting insulation and aluminum siding on the outside. I switched to 3/4" hard foam insul. and luan plywood on the outside over that and then all new aluminum sheeting over that. The build thread goes into quite a bit of detail, which may be of some help or interest to you. It is very solid but I do have a few ripples in the aluminum from heat expansion. I didn't use the right adhesive and probably should have used more screws for the sheeting. Structurally it doesn't seem to be a problem, but doesn't look as nice as it did new.
Vic
Vic
Tom,
Engineers vary in how much common sense they have so please don't hold that against me.
For what people are trying to do on this forum, it is more trial and error, just seeing what works and what doesn't. I am trying to follow along like everybody else and figure out what works for what I want. What people are doing by making test pieces and subjecting them to reasonable testing is very smart.
To me the problem with traditional RV siding methods using aluminum or Filon is not the material itself but the joints, wall-to-wall or wall-to-roof. They have too many problems with leakage. The last camper I built was wood framed with traditional aluminum siding. It made me very interested in stitch and glue boat building and the use of epoxy and fiberglass.
This link http://bateau2.com/howto/ply_test.php shows how much stronger 1/4" plywood is when covered on both sides with one layer of fiberglass.
If you do end up changing your aluminum frame design, look at Lance camper construction as they only use 1" square aluminum tube.
Engineers vary in how much common sense they have so please don't hold that against me.
For what people are trying to do on this forum, it is more trial and error, just seeing what works and what doesn't. I am trying to follow along like everybody else and figure out what works for what I want. What people are doing by making test pieces and subjecting them to reasonable testing is very smart.
To me the problem with traditional RV siding methods using aluminum or Filon is not the material itself but the joints, wall-to-wall or wall-to-roof. They have too many problems with leakage. The last camper I built was wood framed with traditional aluminum siding. It made me very interested in stitch and glue boat building and the use of epoxy and fiberglass.
This link http://bateau2.com/howto/ply_test.php shows how much stronger 1/4" plywood is when covered on both sides with one layer of fiberglass.
If you do end up changing your aluminum frame design, look at Lance camper construction as they only use 1" square aluminum tube.
Greg,
I certainly hold nothing against engineers. I work in the construction industry building very high end Mac Mansions, 15,000 to 30,000 square footers. Definitely over the top, not sure I agree with it, but very interesting and challenging work. Architects seem to be very short on the how too's so with out our engineers these large homes would be disasters. It takes a special mind to be an engineer!
As far as RV's leaking I came to the conclusion there built to leak, maybe unknowingly. I think with just a little change in exterior trim detail and water proofing materials I think a majority of the leaks would be stopped.
Thanks for the link to the plywood tests I found it very interesting.
I'll check out Lance.
Tom
I certainly hold nothing against engineers. I work in the construction industry building very high end Mac Mansions, 15,000 to 30,000 square footers. Definitely over the top, not sure I agree with it, but very interesting and challenging work. Architects seem to be very short on the how too's so with out our engineers these large homes would be disasters. It takes a special mind to be an engineer!
As far as RV's leaking I came to the conclusion there built to leak, maybe unknowingly. I think with just a little change in exterior trim detail and water proofing materials I think a majority of the leaks would be stopped.
Thanks for the link to the plywood tests I found it very interesting.
I'll check out Lance.
Tom
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oneeyedjackass
New member
Also thinking about a build. I made a model so the chief could try out different layouts and get a feel of space.
Version1
Amazing what you can do with a Sierra Nevada box
http://one-eyed-**************.com/wp-content/uploads/2011/02/20110213-102320.jpg
Basic layout v1
http://one-eyed-**************.com/wp-content/uploads/2011/02/20110213-102334.jpg
My view from the drivers seat
http://one-eyed-**************.com/wp-content/uploads/2011/02/20110213-102345.jpg
Version1
Amazing what you can do with a Sierra Nevada box
http://one-eyed-**************.com/wp-content/uploads/2011/02/20110213-102320.jpg
Basic layout v1
http://one-eyed-**************.com/wp-content/uploads/2011/02/20110213-102334.jpg
My view from the drivers seat
http://one-eyed-**************.com/wp-content/uploads/2011/02/20110213-102345.jpg