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Why use plywood?

PostPosted: Sun Feb 26, 2017 1:43 am
by Gator417
OK, I've never built any camper, so I'm just curious on this one. I do have some experience in home construction and remodeling though.
Why does nearly everyone use plywood in their teardrops? Even most on here who are building "foamies" use a lot of plywood.
While you're here, what's the idea behind aluminum skinning?
Thanks,
Gator

Re: Why use plywood?

PostPosted: Sun Feb 26, 2017 1:50 am
by linuxmanxxx
Aluminum skinning is to cover rotting prone crappy plywood

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Re: Why use plywood?

PostPosted: Sun Feb 26, 2017 8:44 am
by noseoil
Plywood is typically easier, cheaper, faster & lighter (when used properly). You can make a house out of solid lumber, but why would you do it? Remember, you aren't building a house with 2x6's, stucco & sheetrock, it's a camper....

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Re: Why use plywood?

PostPosted: Sun Feb 26, 2017 9:11 am
by Gunguy05
Think plane, not tank.....


Best general advice I've gotten concerning building a teardrop

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Re: Why use plywood?

PostPosted: Sun Feb 26, 2017 9:18 am
by QueticoBill
Gator417 wrote:OK, I've never built any camper, so I'm just curious on this one. I do have some experience in home construction and remodeling though.
Why does nearly everyone use plywood in their teardrops? Even most on here who are building "foamies" use a lot of plywood.
While you're here, what's the idea behind aluminum skinning?
Thanks,
Gator


If you ask why ply, what would you consider in its place? Sawn lumber, steel, aluminum, other metal, plastic, other? My reason for using ply is it's ready availability, low cost, and my comfort level of working with it and other wood products for 60 years. An aluminum frame and plastic or other space age skin would be wonderful, but I don't have those skills. If you do, go for it.

Re: Why use plywood?

PostPosted: Sun Feb 26, 2017 12:09 pm
by JaggedEdges
Availability is good, in any small city you still probably have a choice of 3 places to buy it from. If you wanna do rivetted aluminum frames or something, you're probably hunting materials out in a 50+ mile circle.

Also because they made one of the most badass aircraft of WWII out of it... :D
https://en.wikipedia.org/wiki/De_Havilland_Mosquito

But don't let us stop you in your lightweight ferrocement with chicken mesh rebar experiments.

Re: Why use plywood?

PostPosted: Sun Feb 26, 2017 12:41 pm
by working on it
Gator417 wrote:OK, I've never built any camper, so I'm just curious on this one. I do have some experience in home construction and remodeling though.
Why does nearly everyone use plywood in their teardrops? Even most on here who are building "foamies" use a lot of plywood....
noseoil wrote:Plywood is typically easier, cheaper, faster & lighter (when used properly)....
  • Gator- you have experience in home construction/remodeling, but in my case, I did not. My experiences using wood were, at the time, limited, and my "expertise" was in mechanical assembly (machinery at work, cars & engines as a hobby). I planned building a simple, strong structure with easy , "straight" cuts (for the most part) and using steel "brackets", of various types, to bolt-together (using primarily stainless 1/4" carriage bolts, washers and acorn nuts) and glue inside and out on all seams with PL adhesive (much like automotive seam sealer in application). I knew I could build a strong 4x8 "box" using plywood (which was basically the wood I had most experience using), without buying specialty wood-working tools.
  • Plywood is strong-I intended to use 1/2" birch exclusively, but I added 1/4" extra to the floor (for strength and to cover the floor-to-frame attachment bolts)-but, when I returned to the Home Depot for more, I happened upon a killer deal for pre-sanded, phenolic resin-glued plys, 3/4" plywood (for $25 a sheet)- even stronger! True, it made my trailer a lot heavier, but I don't think my trailer would've met my goal of 1000 lbs, even if made of 1/2 foam, due to all the additional items and gear I added to my plans.
  • If I hadn't feared dimpling, or oil-canning, I might've used an aluminum skin, but I went with the polyurethane "mix", covered by tough farm equipment paints ( I had used before), planning to later cover with bedliner (I had used before), if the paint had problems. Even though I also used various screws to strengthen the trailer, and attach items, I basically stuck to my bolt-together trailer, using familiar tools and techniques I had used before. I could not imagine stick-built inner walls, routered-out bracing, rabbetted or biscuited joints, nor trust the strength of pocket screws over bolts/brackets. I've started to use some special tools, and techniques occasionally while rebuilding my house (from the inside out, now that I have time), but I mainly rely on " straight cuts & steel brackets". And I still use plywood, wherever possible.
  • 2 x thickness,identical cuts.png
    2 x thickness,identical cuts.png (248.11 KiB) Viewed 2903 times
  • simple cuts (some mitred angles), bolted & glued.png
    simple cuts (some mitred angles), bolted & glued.png (358.07 KiB) Viewed 2903 times

Re: Why use plywood?

PostPosted: Sun Feb 26, 2017 3:36 pm
by QueticoBill
working on it uses straight, and I like plywood because of its ease of curves - either sawn profile or bent - because it's so much stronger that way. Finding a profile and modifying it so it is only curves - no flats or straights - is my goal. Not to mention plywood is pretty dimensionally stable with changes to temperature or humidity compared to many materials.

Re: Why use plywood?

PostPosted: Mon Feb 27, 2017 12:32 am
by KennethW
Wood? You could go wood less. I did. 2" foam floor and 1 1/2 walls and roof and PMF. I used FRP as reinforcement pads for hinges(bolt thru) with no roof struts.
5x10 ,15000 miles and no problems.

Re: Why use plywood?

PostPosted: Mon Feb 27, 2017 4:27 am
by Gator417
So most use plywood because it is easy to work with, relatively inexpensive, easy to find and people are familiar / comfortable with it. Its convenient. That's pretty much what I figured, but I wanted some feedback from the experts. Plywood is anything but light though. Its probably the heaviest material one could possibly use in building a camper. Not to mention its not used, structurally, by any camper manufacturers. It seems like some folks here have never considered using anything but, while others would never consider using it at all. Very interesting. Thanks for the speedy responses. Fwiw, I'm planning on using foam and laminating it with tyvek or maybe nylon (tent fabric) and possibly covered with frp. Still being drawn out in my head movies though.
Thanks again,
Gator

Re: Why use plywood?

PostPosted: Mon Feb 27, 2017 5:14 am
by Gator417
Also, linuxman, I'm now using your post as my signature. Its that good. If that's not OK, I'll remove it though.
Kenneth, I'm building mine on a 5x10 as well, but it will be removeable since I don't have the budget or space for another trailer. Do you have a build thread from which I may steal an idea or 7?
Gator

Re: Why use plywood?

PostPosted: Mon Feb 27, 2017 6:39 am
by JaggedEdges
Gator417 wrote: Plywood is anything but light though. Its probably the heaviest material one could possibly use in building a camper. Not to mention its not used, structurally, by any camper manufacturers.
Gator


Weight for weight it's as strong as steel and duralumin ... and it used to be used by RV manufacturers.... back when they could build a 24 foot 3000lb trailer, instead of 5000lb and have the cheek to call it a lightweight.

Was it said on this thread or another I was in recently "Think aircraft not tank" the saying went. Stressed skin, part of a composite, not huge slabs of 7/8ths (Edit: yah it was gunguy up there, derp, couldn't see it for the life of me when posting.)

There's some people building with foam, but unless you go real thick with the skin it is prone to dents and not many of them would let you jump on their roof, for larger than teardrop size you probably have to build with bulkheads and compartments, skin both sides.

But anyway, get an 8x4 sheet of your suggested alternative, put it in between two sawhorses longwise and stand in the middle of it, now what does it weight for same deflection doing same with 1/2" ply?

Edit: IF you're thinking that the frame is the strongest part and everything else just loads it down, you're misunderstanding your application of materials, if that were the case, then these houses should have stood up to 200mph winds without all that "baggage" because they were fully framed... http://www.bramptonguardian.com/news-st ... struction/ but no, sheathing wasn't done. Frames just racked. Roof sheathing was there though and roofs landed fairly intact.

Re: Why use plywood?

PostPosted: Mon Feb 27, 2017 9:04 am
by KennethW
Gator417 wrote:Kenneth, I'm building mine on a 5x10 as well, but it will be removeable since I don't have the budget or space for another trailer. Do you have a build thread from which I may steal an idea or 7?
Gator

Sorry I did not do a build thread. At the time I did not Know it would work.
(Foam cooler glued to a trailer covered with canvas going down the freeway at 80 mph. WHAT could go wrong?)
I have a few pictures in the gallery (click on the left).
After using PMF. I would not of used FRP on one side of all the panels. FRP is a little heavy, I would have used FRP as reinforcement panels, door flanges and for the cabin floor above the foam(maybe).
My camper is truly a budget build. If I could build rather then buy I did.
But At the same time I had the crazy ideal of trying to use no wood(no rot) The only wood is
1) the galley wall, ran out of time
2) the galley floor, 3/8 plywood slide between the last 2 beams that is bolted under the frame for 1/3 more galley storage.
3) The Wiley window frames (love the windows) that also reinforces the doors. https://video.search.yahoo.com/yhs/sear ... tion=click

Things I would do different;
I would use glass cutting boards for the windows(light in, frosted but can see out a little),
1 1/2 foam in the roof with no FRP( no need for the FRP and FRP sheets is hard to glue to the foam)
Get a harbor freight sander to run over all the foam before gluing. http://www.harborfreight.com/5-inch-ran ... 93431.html

Re: Why use plywood?

PostPosted: Wed Mar 01, 2017 2:42 am
by Gator417
I think some people are confused at my question. Plywood is the heaviest material one could possibly use in a camper. I'm asking why use it if it is so heavy and prone to rotting and delaminating. In response I get "think plane, not tank". I've built RC airplanes. before. I used either foam or balsa framing with plastic covering. I did use minute amounts of plywood, but they would have never flown if I built them primarily out of plywood.

KennethW wrote:Sorry I did not do a build thread. At the time I did not Know it would work.
(Foam cooler glued to a trailer covered with canvas going down the freeway at 80 mph. WHAT could go wrong?)

That's too bad. Hopefully there is something in your pics I can use, otherwise I'll be bugging you all the time with silly questions. I'm also going for a budget build & not going to use any wood if possible, so I'm looking hard for ideas I can use right now.
Thanks again,
Gator

Re: Why use plywood?

PostPosted: Wed Mar 01, 2017 9:01 am
by aggie79
Your goal for no wood is laudable. That said, I'm curious as to what type of structure/structural material you'll use to anchor/attach your door(s), hatch, roof vent and other "appendages" to your woodless build.