Plywood cut out/frameing for lighter weight?

[tony.latham]

Gee, I clicked the link...

You're probably not burning the right incense....

TL

[grant whipp]

By the way; when GRANT speaks, listen. Let his advice seep like a tea bag. Squeeze the bag between your fingers. Let it's aroma permeate your senses. The builders in Tibet that are monks, believe he's the Dalai Lama of Teardrops. They've got their own forum over at http://www.TibetenTeardropBuildingMonks.org Don't expect to be accepted into their forum without burning a lot of incense. Not the cheap sticks you get at Walmart that smells like somebody threw a plastic fork in your cooking fire.

I bought my hinge from him and I'm thinking he blessed it. ...

What the hell have you been smokin', Tony ... ... what ever it is, I want some ... ...!

Thanks for the endorsement ... ... and kind words (I think ... ...) ...! As always ...

CHEERS!

[tony.latham]

"What the hell have you been smokin', Tony ..."

...well, I had half of a Corona while typing that. A half. I swear. I'm afraid it was the writer in me, creeping down my arms, into my fingers and slithering onto the black keys...

Speaking of listening to the Dalai Lama, I just read now that I outta pull my Fantastic Fan off this summer, clean the damn butyl tape off and get some RV putty tape. Probably the blacks stuff! No big deal.

Tony

[crazycyclist]

How much weight do you save? I think that is an important question.

Starting with at 4x10 side.
Take away 7 sq feet for curves front and back
Take away 6 sq feet for the doors - they can't factor into the weight savings.
That leaves you with 27 sq feet.

3/4 inch plywood is about 2.5lbs per sq foot so each side would weigh 67.5 lbs.

1/2 inch plywood is about 1.65lbs per sq foot to give you 44.5 lbs per side before any cutouts.
1/8 inch plywood is 0.42lbs per sq foot and you need two layers per side to add 9 lbs per side back in.

Assuming you remove 60% of the wood in cutouts the savings in weight over a straight 3/4" plywood per side are as follows:
3/4" core - 31.5lbs per side or 63 lbs total
1/2" core - 40.5lbs per side or 81 lbs total

So the question to ask yourself is, "How much is 60-80 lbs of weight savings in your trailer going to be compared to the additional time and effort it would take to cut out the core, add insulation, and put the 1/8" sides back on?"

Some will argue that the added R-value of the insulation in the walls is worth it. Keep in mind the 3/4 plywood has an R-value of 0.94. Expanded Polystyrene Foam has an R-value of 2.5 (at best) for 1/2 over the 60% of the wall you cut out. So again you would have to ask yourself how much it would benefit you. Part of that answer may depend on the climates in which you intend to use your teardrop.

Keep in mind your savings will vary depending on the amount of curve, size of doors, percentage you cut out, and the type of plywood you use.

[Tinbasher]

In my case 30lbs is the difference between legal and not so in some builds weight is an important design factor. I think the "cookie cutter" method is so popular is that it looks so darn cool

But then we cover it up!!

[tony.latham]

My old tear, with 1/2" plywood walls, had a condensation problem. My new one with sandwiched walls doesn't have that issue. I think it's a lot quieter too. Time will tell on that factor, I've only spent five nights in it.

Structurely, I believe there is a gross benefit with a thicker wall to support and join the bulkheads and roof spars. Mortis and tenon type joinery vs butt joints. (Am I wrong here? I didn't build my first teardrop and am not sure how it was put together.)

On the other hand, sandwiched walls are labor intensive and cost more . Mine are - no doubt- a bit heavier than those built from 1/2" plywood.

Tony

[Gunguy05]

So, assuming a "cookie cutter" design, are the majority of ppl using (and finding it is worth it) 3/4".. or is 1/2" good enough. And by good enough I mean GOOD". I would think that they extra attachment surface area of the 3/4" would be helpful at the edges.

Also, we are doing a 5x10.. What are the thoughts on using 3/4 to reduce warping and flexing on a wider wall... and possibly a joint if I can't find 5ft plywood in my area. We are doing a raindrop style design, so the nose will be stick built, only about 5x8ft of actual flat area on sides. Nose will probably be 3/4 of some sort framing.

[tony.latham]

Note that Grant's internal wall frame is 1/2" ply. He's probably built more teardrops than I've seen.

One of the best decisions I made in my build was to first make a pattern and use that for my plan. It's got cutouts that I used as a router template to fit my bulkheads in and where my counter top sits in the galley and how far it protrudes into the cabin. It was invaluable when I was ready to cut the aluminum for the sides.

Make sure you visit grant's Facebook build thread.

Tony

[tony.latham]

Ps I used 1/4" plywood sub flooring for my pattern.

[RandyG]

My walls are 1/2" cookie cut and I am also doing a raindrop style. My frame is different from any others, it's riveted, so if using 1/2" on a steel frame, it will be more than good. Link below.

[DMcCam]

Our walls were also sandwich style from 'skeletonized' 3/4" MDO (sign board) with 1/8" Baltic birch skins inside and out. We used the rigid insulation and cut it with a scroll saw. One thing you might consider is making all your corners rounded instead of sharp squares. It makes the whole thing stronger.

Happy Building,

Dave

[RandyG]

Agreed, round those corners.

[Gunguy05]

Ps I used 1/4" plywood sub flooring for my pattern.

I was debating on whether or not to do some sort of pattern. I can see how that would come in handy for making all of the "extras" fit. Especially the hatch ribs and the cabinets. I will look into that.

[Gunguy05]

Note that Grant's internal wall frame is 1/2" ply. He's probably built more teardrops than I've seen.

One of the best decisions I made in my build was to first make a pattern and use that for my plan. It's got cutouts that I used as a router template to fit my bulkheads in and where my counter top sits in the galley and how far it protrudes into the cabin. It was invaluable when I was ready to cut the aluminum for the sides.

Make sure you visit grant's Facebook build thread.

Tony

Im thinking of 1/2 now.. I will have a 5/16 inside wall of prefinished flooring running opposite the longest cutouts, so I think that will work well. Also, 1/8 (I think) luan on the outside, so that should be right at 1 1/16" overall thickness. Skinning is going to be Al as far as the plans go now.
The flooring idea is aggie79's, I really like the way that he did his here http://tnttt.com/viewtopic.php?f=50&t=26988&start=30

Well, off to more research....

[lfrazer98]

Note that Grant's internal wall frame is 1/2" ply. He's probably built more teardrops than I've seen.

One of the best decisions I made in my build was to first make a pattern and use that for my plan. It's got cutouts that I used as a router template to fit my bulkheads in and where my counter top sits in the galley and how far it protrudes into the cabin. It was invaluable when I was ready to cut the aluminum for the sides.

Make sure you visit grant's Facebook build thread.

Tony

I looked for the facebook page. Can you post a link to it, please? Happy new year!!