Replies to This Discussion

Permalink Reply by Erich Friend on September 22, 2014 at 12:05pm

Laminated structures require gluing of the layers. Be aware of the glues' interaction with the Styrofoam - some glues can weaken the Styrofoam. Look through Rich Dione's blog posts from a few years back. He discussed laminated structures at length.

You might consider using hex-celled cardboard panels in lieu of Styrofoam.

Either way - consider your options for fire-proofing anything you build for use on the stage. Styrofoam can produce toxic black smoke when it burns.

Be sure to load test it thoroughly before you allow students to walk upon it! Dynamic loads are much more severe than static loads. The failure mode will tend to be abrupt, rather than bending. We don't want a structural failure to get someone injured!

-Erich Friend, Teqniqal Systems

• ▶ Reply

Permalink Reply by Joel Williams on September 22, 2014 at 12:49pm

THANK YOU!

Rich Dione's blog "Non-traditional construction" was exactly the one I was remembering. The only down side is that now I can't get the photos to show...

• ▶ Reply

Permalink Reply by Paul Schreiner on September 22, 2014 at 2:05pm

If I were to try something like this, I'd probably go with 2" extruded polystyrene (blue/pink/green, doesn't matter, just not beaded) foam as the filler. 1/2" ply top and bottom. I'd look into insetting the foam by an inch all the way around to make room for 5/4 splines used to fasten them together (by screwing through the top overhang).

And I'd use copious amounts of white glue to hold it all together. I prefer 30NF blue goo for smaller projects, but the amount of working time you have with it is a lot shorter; and for platform-sized objects, 30NF may be prohibitively expensive. The key is to make sure you have perfect weighting and sandwiching so that the glue makes contact with every available square inch of surface area.

And then I'd find out which scotch my AHJ prefers, so I can get him/her in a good mood before explaining how every side will be covered with rated lumber so having foam on stage isn't such a bad thing.

• ▶ Reply