How thick should the roof be?

[mikeschn]

How thick should the roof be on the generic benroy?

Here I sit, trying to figure out if one layer of 1/8" plywood is enough to cover the generic benroy.

The Lil Diner which Steve built has 2 layers of 1/8" luan plywood plus a layer of fiberglass. I don't think a piece of flying gravel is going to put a hole in it.

But what if you only have 1 layer of 1/8" luan, and what if you only paint it, instead of putting aluminum or fiberglass on it.

Your thoughts?

Mike...

[toypusher]

Two 1/8" layers should hold up to about anything that you would normally get as road debri.

[SteveH]

Just my 'opinion", but I would only use one 1/8" ply if it's going to be covered with aluminum.

[mikeschn]

What about 1 layer of 1/8" luan and a coat of paint? Is that strong enough?

Mike...

[GeorgeTelford]

2 Layers of 1/8 will be stronger and more resilient than a single 1/4 pce.

Reason in 1/4 there will be more strain caused by the curvature, this extra tension makes shattering and splitting more likely.

2 layers of 1/8 over same curvature will be far more supple, any object striking is likely to be "bounced"

I think a single layer would hold up well too.

I just pounded a pce of 1/8 ply with a 40 mm pce of foil backed foam insulation behind it, using a golf ball sized smooth rock, result no smashing, made a mark like a ball-peen hammer on copper sheet.

With ragged rock small gouge, but repairable.

With load spreading insulation behind its damned strong.

[Steve Frederick]

What about 1 layer of 1/8" luan and a coat of paint? Is that strong enough?

Mike...

If it's over a core of insulation, and fits tightly, I think it would only dent if struck hard. You might have to repair the paint.

[mikeschn]

I just tried a very unscientific experiment. Using 3/4" EPS as a backing material, and a ball peen hammer as the weapon of choice, I gave this piece of 1/8" luan a medium force hit. The results were less than favorable.



Then I took a piece of 1/8" baltic birch and gave it the same medium force hit. It barely made a dent. And baltic birch bends easy enough if you bend it with the grain. And it's available if 5'x5' sheets. I think that baltic birch will be my first recomendation, and 2 layers of 1/8" luan will be my second.



Mike...

[Steve Frederick]

Off topic, How's the 'Diner coming? Want me to make you a wooden grill for the A/C??
The shop's empty again, and the axle for the next one's not ordered...yet!

[mikeschn]

How would you make a wooden grill?

I was thinking about cutting something on the cnc machine. Of course the slots would be rather large, but what the heck, it's pretty dark in the ac hole anyways.

As for the rest of it, I'm making some progress. I am using 1# bottles for the stove after all. I have it set at the optimum angle to boil the propane. Now I need to have a hose/tube made.



Mike...

P.S. What would it take to add a second door into it? I would not want it to be 36" wide like the window.

[GeorgeTelford]

Hi all

All I had was birch ply, Mike your pictures sure beat the hell out of me just describing it



I think it shows 1 layer would be good enough as long as it wasnt luan

[Arne]

Depends on if you plan on dancing on it....

My take is the curve parts can be 1/8" because the curve makes it more rigid.

The flat can be 1/8" IF the rigid insulation fills the voids and supports the 1/8"..... but 1/8 with no support is a bit of a stretch.

[Toolie]

Mike - what is the optimum angle to boil that propane?

[mikeschn]

The optimum angle is the angle that exposes the most surface area of propane inside the bottle without blocking the flow out the top when the bottle is new. It might be between 15* and 30*. I'll measure a couple appliances I have this evening.

Mike...

[Gage]

To get back to the original question. My roof is 1/8" birch, 3/4" foam, 1/8" birch and then .060 alum skin. My cross braces are 1"x 2" laying flat spaced about 16" apart. There has been about 200 lbs standing on top with no damage or stress. Just the way I did it and it worked for me.

Have a good day.

[GeorgeTelford]

Hi Gage

The original question was not as far as I can tell "how did Gage do it?" Just struck me as odd that yousay back to original question and then ignore it yourself.

Mike was wondering

"trying to figure out if one layer of 1/8" plywood is enough to cover the generic benroy? "

and also

"But what if you only have 1 layer of 1/8" luan, and what if you only paint it, instead of putting aluminum or fiberglass on it?"