Help me build a ramp

curtis73

Well-Known Member
Have a picture. Question to follow.


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This is the set I'm building. Relax... I have a week and a half before we open. Cast of 7, community theater, show runs for 10 performances plus 3 dress rehearsals


The ramp indicated by the red arrow folds up, and the two walls indicated by the blue arrows fold in. The whole thing is a cube that opens up to what you see here. The ramp wall is 12' wide and 11' long/tall. Up to 7 people walk on it, although I don't think they're ever on it at the same time.


My first thought was to use some aluminum I-beam extrusions I have. I have 4 that could span the 11', so I would put them at 0, 4, 8, and 12' as stringers/studs. Then in between I was planning on several 1-by spans between the aluminum, skin it with luan, and fill the cavities with 2 lb urethane foam. Unfortunately, that will cost about $600 in foam.


Enter idea #2. Have another picture:


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I need to make this thing rigid enough to hold some people, but light enough that two people can fold it down/up. Is there some sort of adhesive I can use to laminate some polyiso insulation sheets together, then use that same adhesive to make a stress-skin platform by laminating luan onto it?


I know epoxy would work, but we'd be spending as much or more on epoxy as we would the expanding foam.
 
I've heard that, if you're quick about it, you can use expanding foam as the adhesive for these sorts of constructions. Probably the "window and door" kind would be better. Apply thinly and clamp strongly. Some construction adhesives also bond rigid foam insulation well (and many do not). It's not necessary to have a super ultra strong joint between the skin and the foam; the main purpose of the foam core is to keep the skin from bowing in or out, and so keep it rigid.

If you have an RV repair place nearby, you could enquire what they use as this sort of laminated construction is very common in RV walls (and RV floors and roofs sometimes as well). I do know they have a few other adhesives that are often used, but I don't know offhand what they are exactly.
 
Neutral 30 is a 3M Latex based contact adhesive used for adhering foam it works on EPS, Styro etc. you can also use it to glue Luan to foam. <that's how I build jigsaw cut boards.> I'd secure the luan to the aluminum or steel framing with a t-nailer or other nail system designed to secure wood to metal framing.
 
How about luan to aluminum?
I just found a CL ad for a couple of old aluminum extension ladders. Bingo... extra I-beams with crossmembers already in place.
 
Neutral 30 is a 3M Latex based contact adhesive used for adhering foam it works on EPS, Styro etc. you can also use it to glue Luan to foam. <that's how I build jigsaw cut boards.> I'd secure the luan to the aluminum or steel framing with a t-nailer or other nail system designed to secure wood to metal framing.

This is a viable thing. Looking into it now. I solicited a donation of a couple 24' extension ladders to get more framing. If I can fill the voids with foam to stiffen up the voids, I can go thinner on the decking
 

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