Anyone experienced with ply?

why not look at www.glen-l.com although a boat site they have a number of DIY slide on off campers with all the material specifications ...personally I would be glassing he outside with cloth like the underside of a stitch and glue boat .. I noted at the ply yard yesterday they have thin white coated ,,,caravan ply,,,,,for the interior sheeting of your van

 

So, do you think the 7mm or the 9 mm?

 

depends how big it is ..what curves you put in it and what interior structure ..personally I would be looking at a thin outer skin ,frame and insulaton with an inner ply skin .....look at the glen l site ...did you weigh a panel ?

 

Thanx.
I found something in the Glen L that said Ply is stronger than fibreglass. He prefers to use thicker ply and less fibreglass.
Now I cant find that page to see what else he has to say.

 

you need to look at camper trailers on the site ( left menu) and you will find build photos like this . I would be looking at caravan ply on the inside ..frame with insulation and small square profile zincalum sheet for the outside ..remember that the furnature and fittings often stiffens the sides ........re the boats ..its when you put a curve in the ply and hold it with the fibre glass that it becomes stiff ...ever seen a car with flat panels ? take the lid off a shoe box and see if its flexible (holds its shape when twisted)...dont underestimate the need for insulation in your van .. even if you use foam sheet inside or out the ply ...

 

A thin layer of glass cloth on the outside will make it last years longer. 6mm is thick enough. I didn't glass my homemade camper so the Florida weather rotted it.

 

Nissane,

For what it's worth - several years ago I built a camper onto my Ford F-150. It was NOT a slide out, it was built right onto the box. I started out by gluing (I used "Tough as Nails" for bonding the 2x4s to the top of the truck box, NOT wood glue) and bolting a 2x4 on the 3 top sides of the box. (I dropped the tailgate to allow for an additional 2 feet of interior space 10' instead of 8'.) The dimensions were Floor area = 5.5x10, Roof area = 5.5x13 (I extended over the cab 3 feet for storage.) Inside height = 6 feet. I used a 14' long 2x4 for each side of the roof supports so there would be no question on strength for supporting the 3' overhang in front. For the front and back I used 1/2" ply, on the sides I used 1/4" ply. I used 2x2s for the framing. I also glued and screwed EVERY area where 2 pieces of wood were joined. I cut each piece to fit, clamped it into place, pre drilled a pilot hole, removed the piece, applied the wood glue, reinstalled the piece, and then drilled in the screw. Ply wood panels were screwed every 6 inches, taking care to place each screw in locations that would not conflict with other screws being placed in different directions, as when installing the interior cabinets. I used a 2' spacing for the 2x2 framing however there was some noticeable bowing in the side (1/4') panels so if I were to build one again I would go with 16" spacing. This truck was involved in a collision (The other guy ran a red light.) but the camper was not damaged in the least! I was so impressed with the added strength by using the "Glue and screw" method. This gives much better bonding then nails alone. And screws wont back out of the wood as it expands and contracts with the weather. The outside was primed and painted white. Using white will greatly reduce the inside heat! I first painted the roof black and then re-coated with white and discovered a big difference in the amount of heat that would build up inside the camper. White is the way to go!!!

I hope this is helpful.

Chuck

 

Wow. That's bulletproof.
This is something like what I am planning to build. It's going to have a pop up roof. I'm trying to keep it light and the centre of gravity low low so it doesn't tip over when I'm off road driving sideways under low trees.
http://www.freedomoffroad.com.au/images/292-850sd-poptop.jpg

 

I should also mention that I upgraded the leaf springs to stabilize the load. I replaced the 150 springs with 250 springs AND had them add an extra top spring. (Rear axle only.) And I also put 3 ply walled tires on the back. I designed my camper for cross country travel so I wanted to be able to stand up comfortably to prevent feeling too confined if I got stuck in bad weather for a few days. But you can always set your roof low if you plan on sitting most of the time. My only problem with "pop-up-tops" is the set up and take down. I wanted to be able to "Park and sleep" without having to spend extra time setting up the camper after a long days drive. Also, I never intended to do much off road driving beyond the normal camp ground trails. No "stump jumping" although it did have 4WD to get me in and out of the mud if needed. I should also suggest that you carefully consider how you set up the bed. I set mine up across the front of the box which came out to be about 5.5x4. Not bad if you like to sleep on your side and with your knees bent a bit. I am 5' 7" and sometimes like to be able to stretch out on my back. You can't do that when your head and feet run out of room. So another change I would make in my design would be to place the bed on a fold up/out shelf, about 2x6 feet. That way I would have the room to sleep better and I can fold it up and out of the way during the day for more space. But you really have to set things up for the way you will be using it. Another thing I designed into the sink area was a hinged top that covered the 2 burner gas stove. That way I could put the sink and the stove on the same counter and also have counter space for working. I could flip up the counter top to access the cook stove, and close it for counter space when washing the dishes. I also hinged the bed platform for additional storage space for things like drinking water, a slide out port-a-potty, and an extra 12 volt car battery to power the internal lights, which I connected to a small battery charger. The charger was set up to switch between 12VDC and 120VAC via a 120VAC relay so that when I plugged into power at a camp site the charging system would automatically engage. The thing about designing your own camper is that you can add what you want. You are only limited by your imagination. I took measurements, drew plans, and made a list of "extras" that I wanted it to have. I put a lot of thought into it before I went out and bought the materials. I knew it inside and out, right down to how many screws I would need! That project was a great achievement, to be able to design and build something like that and have it turn out so well.

Good luck.

 

Strength comes from the design as much as the ply skin. For example, I built a 7' x 7" x 8" float using door skin, which is supposed to be 1/8 but it closer to 7/64, and only luan, not the strongest of woods. The raw ply flopped all over the place and could be snapped easily by hand before it was assembled. The float had only 5/16" square chine logs and a couple of ply frames, well lightened by holes.

Weight was only 8 lb. However, when it came to destroy it (just an experiment) I wanted to see what it could take so I blocked the ends up on bricks and stood on it. Didn't creak. I jumped on it; nada. 2 of us stood on it, combined weight nearly 450 lb, stamped (not enough space to jump) and again it didn't break or even creak. It felt much stiffer than the floors in my house. I attacked it with a 2-handed axe, hit a chine and the axe bounced off, although it did leave a dent. Finally I had to saw it up. Plywood can be incredibly strong and stiff when properly handled.

I have built several canoes from 3 mm marine ply and they are not in the least delicate, although not glassed, although I don't recommend it for a sailboat. Glassing plywood increases its strength and stiffness tremendously. As the glass layer becomes thicker the wood's function morphs into a spacer between the glass layers, the ply's strength is less of a factor, but it is still important that it be void-free.

If the ply is glassed it is important that the ply is totally sealed, otherwise the moisture will get in and may not be able to get out again, causing rot, potential adhesive failure and buckling of the glass skins if the wood core becomes spongy.

 

stonedpirate, just to get this thread back on track,--Serge and his brothers had a steel fabrication and boatbuilding business in Brisbane, he had considerable experience in the trade and did not have to second guess any thing he did, he went after that record with his eyes open and clear of any drug haze and had complete support of his family through the whole venture.
After setting the record he spent many years delivering vessels all around the world, he had shown he is a dependable kind of guy and not full of bovine shizen like you.Long before you were born a chap name of John Guzzwell set the record with "Trekka" then a Canadian name Wayne Howard Smith had "Happy" designed and built by Jay Benford, she was 15 ft. He got as far as Vanuatu and parked her on a reef. After salvaging all he could he got Benford to design another in alloy at 9ft' claiming that was all the space he used in "Happy". The new boat became "Happy 2" (she was constructed at Port Vila) then sailed across to Mooloolaba, I was there when she arrived, about early 1974-5 where it was impounded by customs and quarantine. He was fined heavily and Wayne was deported along with his belongings. The boat is now on display at the South Brisbane Marine Museum. He lost it because his paperwork was incorrect. If you are intent on your crazy quest then get over here to Brisbane with camera and tape measure. I know Jay Benford would not sell you any plans and you will get no response from Serge either. Actually I believe Serge got "inspiration" from that very vessel. I do have photo's of her but am not clever enough to post on here. regards Ray