Material ?s: building light, large door (8x16 range)

Uncle Dirtnap

Active Member
Hello!

I do much of building using 1x2/1x3 and luan- very strong, super light, and inexpensive for the surface area. I think I may be exceeding the limits of this technique, and I'm worried I'm getting close to that point where recursive "it's so heavy so it needs to be stronger which makes it heavier so it needs to be stronger " goes off the deep end.

What I would love is a set that open like a dollhouse- basically 2 8' wide, 16' high doors. These would. Hinged on the outside.

I know I could manage 8x 8, maybe 8x10 with steel cable diagonals and 1x4 rails.... But 8x 16? Am I crazy?

There will be some mild structural/ decorative add one for stiffness- like a 4"x 4" box across for a separation between floors, or maybe a very shallow faux bookcase, just for rigidity.

Thoughts?

Thanks-
-rj
 
Hello!

I do much of building using 1x2/1x3 and luan- very strong, super light, and inexpensive for the surface area. I think I may be exceeding the limits of this technique, and I'm worried I'm getting close to that point where recursive "it's so heavy so it needs to be stronger which makes it heavier so it needs to be stronger " goes off the deep end.

What I would love is a set that open like a dollhouse- basically 2 8' wide, 16' high doors. These would. Hinged on the outside.

I know I could manage 8x 8, maybe 8x10 with steel cable diagonals and 1x4 rails.... But 8x 16? Am I crazy?

There will be some mild structural/ decorative add one for stiffness- like a 4"x 4" box across for a separation between floors, or maybe a very shallow faux bookcase, just for rigidity.

Thoughts?

Thanks-
-rj
@Uncle Dirtnap Does it need to tour? Can any of it be screwed or stage-screwed in to your deck?? When you build, do you screw and glue all joints??? Covered single or double sided???? Large sturdy strap hinges screwed or bolted in to solid structure vs. smaller hinges anchored into edge grains or thin luan????? No; I don't think you're "crazy" to answer your hopefully rhetorical query .
Toodleoo!
Ron Hebbard
 
I did doors that were 6ft wide and 7ft tall so not quite as big as yours (nowhere near as close) using 35x70 pine frame with a double skin of 3mm MDF and a stud where I had to join sheets on the face. I then hinged them on the outside like you want to and used a windscreen wiper motor and bike cogs and chain to operate it. The biggest problem I had was when swinging the door open that it did not pull the set forward with the weight and drag on the floor. There was only about 15mm clearance. There was lots of bracing and counter weighting to get it to work but in the end it did. the set was a permanent fixture on stage so if I had to make it come and go there would be no way I could have done that.

A stiff frame made out of light materials (think box tube) and then a skin to keep it rigid (the luan would do it) and you may not need any wire braces.

Have fun

Geoff
 
Ron: first-thank you. You never take safety for granted and keep our collective heads screwed on straight.

The piece will be screwed into the floor and we have liberal freedom to back brace and weight it. We glue everything - usually glue and 18 guage staple, but do screw when joining the 1x. Giant strap hinges are looking like the way to go. Skinned both sides-

Hmm. Framing a door out of box steel or aluminium is interesting, but I'm out of my depth with thicknesses and profiles required. 1" box steel? "T"? Angle iron? Tubes? Augh!

-rj
 
My gut is that 1x4 frame, double-skinned would be stiff enough. The second skin does a ton. The weakness would be across the seams of the sheets; I'd probably run my 16' framing on edge, 2' on center, and the 8' framing on flat, dadoed into each side of the 16' pieces, to give a big wide glue surface.

Or, if you can do steel, I'd say 1x2 on edge, with 2x2 on seams. Lightest gauge you can get; probably .065.
 
With it being only 8' wide I'd also be pretty comfortable with 1 by 3 framing and a skin on each side. But they call be 'Butch' because I tend to overbuild things and I'd butch this up a little. Instead of using 1 by 3 I'd get 5/4" by 12" stair tread in 'clear' pine. A lot of places call it Arkansas pine, it has very small knots and is tough as nails. Then rip it down to 3" true. The stuff ain't cheap and if I was on a budget I'd go to the lumber yard and pick out a bunch of the nicest 2 by 4's they had that were straight with as few knots as possible and then rip them down to 1" true by 3" true. There will be some that will bend and become rejects, but I can usually find a use for them in other projects. Where the two sheets of laun meet I'd use a piece of 1 1/2" by 3" true so that there was plenty of width for glue and staples. I'd use three strap hinges, one at the top, one near the middle, and one at the bottom with blocking added so that they have something to bite into to. I'd also put those hinges under the luan (for appearance reasons) using a router to create recesses in the framing and blocking. And if I was worried about the possibility of the far end hitting the floor I'd hide a straight caster in there too.

The fixed side of the hinges is more important as it's what's keeping the whole thing from falling over. If it isn't a giant mass of scenery you could use two triangular jacks made out of 2 by 4's. Set then 90 degrees apart and screw them to the floor (or pile a bunch of weight on them) and they'll be solid.

We used all these tricks last year when we had to make a box set that folded flat as it split in half and rolled offstage for a production of Peter Pan. The wing walls that folded in were 12' wide and 10' tall with doors in them and large open areas with scrim 'paintings' so the people flying the kids could see through them. It took the stage crew a while to get the motion down, but once they did it was poetry in motion.
 
I read it as 28' x 16' - and thought it was maybe two 14' wide.

I think you have to decide on pivot possibilities and select one before you decide how to build it. It could be a unframed drop ( or 1 x 2) if you had a rigid enough pivoting batten at the top and could operate it. If it all has to be ground supported, I so along with an on edge framing and skinning both sides. I'd probably support it on casters or glides- both bottom corners with a pivot that lets it rise and fall a little since no floor is level. A pipe through it or at the edge, firmly attached at floor and braced above the "door" would be nice.
 
For Mary Poppins I built almost exactly what you are describing.
2 8'x16" doors on a rolling set. My doors were 2x4 framed and 1/4" luan skinned. They were hinged to the main unit with really big industrial gate hinges and had 2 6" casters at the end supporting the weight. Nothing that big is likely to be light, so work how you are going to support the weight and you will be fine. Good Luck!
Here is a link to our set opening.
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Ha! This is also for Mary Poppins, the spring musical in Palm Harbor High School in Florida. I'm sitting down to draw out plans and a lumber schedule now, but get to a point where I have to reinforce so much it will

2x4s would work. They are just so heavy, but I guess it's inevitable. How did you support the main structure moving? I would imagine it would want to fall over....of course, having the ends of the doors on casters solves most of that. How deep is the main house?

Thanks-
-rj
 
We did balsa cores with gatorboard (1/2" I think) skins.

Balsa is now foolishly expensive, but I bet 1" blue construction foam on gatorboard skins would work...
 
2" blue construction foam

I wish I could ignore it but have to point out that the Life Safety Code prohibits that kind of use of XPS (and EPS). You might be able to cover it with enough fabric and glop to meet code requirements, but probably have negated weight savings.

Here's the language. Don't be emboldened by the permissive language that relies on testing - because you won't find it done by others and can't afford to have it done. And don't think you can glue a bunch of 1 pound pieces together to use 12.7.4.4. I agree that based on seeing a lot of theatres, especially high school, this is an oft violated law.

12.7.4.3 Exposed foamed plastic materials and unprotected materials containing foamed plastic used for decorative purposes or stage scenery shall have a heat release rate not exceeding 100 kW where tested in accordance with one of the following:
(1) UL 1975, Standard for Fire Tests for Foamed Plastics Used for Decorative Purposes
(2) NFPA 289, Standard Method of Fire Test for Individual Fuel Packages, using the 20 kW ignition source

12.7.4.4 The requirement of 12.7.4.3 shall not apply to individual foamed plastic items and items containing foamed plastic where the foamed plastic does not exceed 1 lb (0.45 kg) in weight.
 
Ha! This is also for Mary Poppins, the spring musical in Palm Harbor High School in Florida. I'm sitting down to draw out plans and a lumber schedule now, but get to a point where I have to reinforce so much it will

2x4s would work. They are just so heavy, but I guess it's inevitable. How did you support the main structure moving? I would imagine it would want to fall over....of course, having the ends of the doors on casters solves most of that. How deep is the main house?

Thanks-
-rj
The unit is not top heavy at all, the weight is on the bottom half, and the top is just a shell.
The main unit was 16' wide and 4'deep. The unit closed was about 5' deep. Use really good casters and you can handle the weight. Good luck!
Screen Shot 2019-02-05 at 2.06.41 PM.png Screen Shot 2019-02-05 at 2.06.20 PM.png Screen Shot 2019-02-05 at 2.04.56 PM.png
 
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Yes, yes BillConner! I should have recommended something like Celtec or some other EPVC that meets UL1975.

Sometimes my dusty brains are addled...
 
The unit is not top heavy at all, the weight is on the bottom half, and the top is just a shell.
The main unit was 16' wide and 4'deep. The unit closed was about 5' deep. Use really good casters and you can handle the weight. Good luck!
View attachment 17491 View attachment 17492 View attachment 17493

So I'm thinking... I build the doors as 2x4 stud walla, 2ft on center, with 16' 2x4s (obviousy some bits at 8' to staple in to)? That's pretty straighforward, if I have it right-

-rj
 
I would favor lighter construction. If covering both sides with ply or other sheet goods, I'd probably use 1 x 4 rather than 2x4, and probably 24" on center. Just my preference to be able to lift something myself.

The braced foot as seen in the video in the form of decorative piers and such if not aesthetically objectionable would make it pretty simple and sure to work.
 
I prefer lighter as well, but I'm running into supply issues. Would you still feel the same if I was unable to get 16' 1x4s? I have no way to rip 2x4 down at that scale. The longest 1x4 I can find locally is 14', and 1x3s are all 8'. I could just use 1x4, stagger the joints and reinforce with a piece of clear 1x2 on the sides daughter-board style. Would that be good enough? That would be my preference, but this scale is bigger than I am used to. Then again, it's only 2'.....

-rj
 
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I prefer lighter as well, but I'm running into supply issues. Would you still feel the same if I was unable to get 16' 1x4s? I have no way to rip 2x4 down at that scale. The longest 1x4 I can find locally is 14', and 1x3s are all 8'. I could just use 1x4, stagger the joints and reinforce with a piece of clear 1x2 on the sides daughter-board style. Would that be good enough? That would be my preference, but this scale is bigger than I am used to. Then again, it's only 2'.....

-rj
@Uncle Dirtnap Glue, GLUE, GLUE is the clue. (And large, clean, surface areas for the glue to bond.)
Toodleoo!
Ron Hebbard
 
I'd have to sketch but 8s and 10s and just overlap or all 8s and scab a splice on. Some folks would not like the cattywampus quality of the overlap but once skinned, who knows?

I'd like to see of solid foam and ply skins with just a perimeter 1by frame would be cost effective.

I've been reading about ghetto fibreglass - cloth (harbor freight or similar drop cloths) and titebond - and wonder if that would work over just foam. (AKA PMF or poor mans fibreglass) Lots of folks have built a teardrop trailers using just foam and cloth on a utility trailer - so don't laugh - they go down the highway at 75 mph through rain and wind and do fine.. Quick construction - layout a double layer of 1 1/2 or 2" foam on floor, glue together maybe with a 1 by perimeter frame, and slather on the titebond and cloth.

(If you do it you have to write about it and publish it!)
 
I would favor lighter construction. If covering both sides with ply or other sheet goods, I'd probably use 1 x 4 rather than 2x4, and probably 24" on center. Just my preference to be able to lift something myself.

The braced foot as seen in the video in the form of decorative piers and such if not aesthetically objectionable would make it pretty simple and sure to work.
Bill is correct, we added little architecture bump outs (planters on the outside and a table on the inside) to hide the casters and to allow us to spread the footprint out to add stability to the swinging doors. We left a gap onto inside to receive the bump outs when the doors were closed.
If I had to do it over, I would definitely look to lighter materials. The set was a beast.
 

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