Newb Question about plywood and TTT construction.

[stu_stumble]

Hello All. I am planning on building a 5X8 TTT. I was thinking about using 3/4 plywood framed out with 2x2's for the floor and then just using 3/4" plywood for the side walls as I would not need to do a sandwich insulation as I would only be camping spring, summer and early fall. Plus I figured this would make the build easier as I would basically just cut my sidewall profiles and then connect them to the floor and then to each other with the roof spars and then cover the roof and hatch with 1/4 plywood. I basically got the idea for this simple build from Wikipedia as someone had posted how to build a tear drop on their and this is how they constructed theirs.

My questions for you all is will this be sturdy enough constructed like this to hold up being towed down the road and also would this be way too heavy. I will be pulling with a 2004 Chevy Colorado so I can pull some pretty good weight.

Also I was looking at Menards today. (This is a store like Lowes or HD but they have these also in Nebraska where I live.) They had Luan plywood, Maple Plywood and Oak plywood. I was wondering which would be best to use for the build and was also wondering if anyone could enlighten me as to how much a 3/4" 4X8 sheet of ply weighs.

Also, was wondering if Titebond III was a polyurethane glue as the Wikipedia thing I read said to use that type of glue. I really appreciate any help you guys and gals can give me on this and I apologize for asking so many questions. But I know I came to the right place to learn.

[CarlLaFong]

A typical sheet of 3/4 ply weighs about 75 lbs
Titebond III is a PVA glue, not polyurethane
The construction method that you listed seems sound. If you're using a HF trailer and building a minimalistic trailer, 800 pounds is easily achieved. Weight goes up with extras, but 1200 pounds will get you a lot of bling

[myoung]

3/4-inch plywood for the walls should allow for faster construction, but would be quite a bit heavier than 5 mm ply over a core of 3/4 inch furring with foam in the openings. Regardless of the weather and temperature, insulated core construction has advantages of lower weight, better insulation, more strength (think i-beam), and more soundproofing.

5x8 seems rather small for a TTT, also. Seems more like TD dimensions to me.

[hoytedow]

I would definitely go with the 1/4"(6mm) plywood on light frame construction. You will be glad later that you did. You can always add a little wood to re-inforce any area where you need to add accessories such as window framing etc. 1/2" plywood on 2-by frame is all you need for the bottom. It isn't a dance floor.

[Robbie]

I am building my benroy TD very similar to how you have outlined yours. I followed Mikes Benroy plans for mine. But I used 1/2" OSB with 2x2 subfloor for the bottom with 3/4" AC Fir ply walls and 1.125" poplar roof spars with 1/8" inner and outer skin. I used Loc-tite Poly construction adhesive for my entire build so far but have switched to liquid nails in the less critical places as its much cheaper. I am only insulating my roof as we only camp from about March/April to September.

Your build plan looks good! I've looked at those plans on wikipedia and they seem pretty thorough. If your building a 5x8 and don't want to hang the cab over the trailer sides (like would happen with a HF trailer) you should look into building your own trailer. Could give you a more solid base and be cheaper.

[stu_stumble]

Thanks for the info, tips and support everyone. Now I've just got to get around to actually building this thing.

[angib]

Solid 3/4" ply has quite a bit to recommend it, particularly for simplicity and toughness - and I'm normally the one praising light weight structures.

My weight estimating data (in PDF table or Excel spreadsheet form) shows that the weight difference isn't that great. Indeed the construction some folk like of 1/4" ply + 3/4" framing + 1/4" ply is about the same weight as solid 3/4" ply and either of these is wildly stronger than is needed.

If you're willing to go to 1/8" skins then sandwich construction will be a lot lighter.

[Robbie]

You could also opt for a lighter material elsewhere to make up for the solid ply walls. I got a bunch of scrap lite-ply from my work to use for all the interior wood (cabinets, shelves, etc.). A full sheet of lite-ply is just over 30 lbs. so about half the weight of regular plywood, and it is very sturdy and stiff still.

[LarryJ]

Solid 3/4" ply has quite a bit to recommend it, particularly for simplicity and toughness - and I'm normally the one praising light weight structures.

My weight estimating data (in PDF table or Excel spreadsheet form) shows that the weight difference isn't that great. Indeed the construction some folk like of 1/4" ply + 3/4" framing + 1/4" ply is about the same weight as solid 3/4" ply and either of these is wildly stronger than is needed.

If you're willing to go to 1/8" skins then sandwich construction will be a lot lighter.

I've been through your site a hundred times and this is the first time I've seen this document - you are just a treasure trove of useful information.

Thank You!!

[Shadow Catcher]

Our tear is 1/8" outer Filon skin 1/8" inner skin and 1X1.5X.060 aluminum framing. I am reminded of the individual that built there tear out of four ply fiberglassed cardboard. This is an airplane you are building not a tank.

[gww25]

The thing to watch out for when doing your weight estimates is that most of the 'published' tables for weights of materials are pretty poor to say the least. Fortunately most err on the heavy side. The usual 1/8" skins on a 3/4-inch frame is usually the lightest construction method. This method does not scale well so a small 4x8 sidewall doesn't benifit as much as a 5x10 sidewall for example. For small trailers the solid 3/4-inch plywood has similar weight and is a lot easier to fabricate but as you go up in size a composite wall starts to gain from the standpoint of weight. For example a standard 4x8 sheet of 3/4-inch plywwod weighs around 75 pounds but a 1/8-inch skinned composite wall 6x10 feet also weighs around 75 pounds.

[suckerpunched]

I buil my 4X8 tear with 3/4 floor and walls,,,roof is skinned in and out with 1/8 birch ply and 3/4 insulation. I was able to keep it under 500 lbs so I didn't have to register it. Plus the fact that I tow with a ford ranger with a 4 cyl which still struggles on steep grades.
TC