How to make large (inexpensive) breakaway glass - Isomaltitol?

WFair

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Houston, Texas, United States
I have been researching breakaway glass options for a large window. Clearly alfonso's sells the best "real deal" but it is much too expensive (several thousand dollars) for the high school production I am working on. I am trying to make a large window that an actor can dive through. I could do it out of balsa and saran wrap, but I really want something that is more realistic as this is in an intimate space (small blackbox theatre).

One (very expensive) option is to use a urethane liquid (like "SMASH! Plastic" from smooth-on) except this is a large window and multiple performances...simply too expensive at about $215 per gallon.

The next option is to make more traditional "sugar glass"...which has plenty of videos on YouTube and instructions elsewhere. Sugar is very cheap. The issue there is that it typically is cloudy (if you can't vacuum pump out the air bubbles) and it tends to caramelize and turn yellow...almost impossible to keep it clear.

I found a sugar alternative called Isomalt which presumably would have similar breaking properties as other sugar glass. I have NO IDEA if this is true, but it seems likely based on what I have read. It is less prone to caramelizing (yellowing) and because it can sit at high temperature in an oven for a few hours, I can let the air bubbles come out of it before pouring. I think this would be my best option, as it will give me the clarity I need and costs only moderately more than sugar. A known issue is that if it absorbs the humidity it becomes sticky, and then recrystallizes to a cloudy surface. My concern is that I live in a place with very high humidity and thus I am worried about it becoming sticky and subsequently cloudy.

So I have two questions:
1. Has anyone tried making breakaway glass using Isomalt (specifically chemically pure Isomaltitol that has not been blended with other sugar substitutes)? How were the results?
2. Has anyone ever tried applying (spraying or brushing) a thin clear high gloss polyurethane coating over an isomalt "glass" object? I wonder if there would be any reaction (melting, yellowing, etc) or if it would just form a thin protective moisture barrier? Any other ideas for keeping it from reacting with the air?
 

ruinexplorer

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First off, do you really "need" glass? Often we shy away from it due to unwanted reflection or glare. What about just a frame with a sound effect?
 

WFair

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I don't suppose we ever really "need" anything for live theatre...but yes. In this case having glass is fairly useful. The window is only on stage for this one brief scene so glare/reflection is not much issue, the theatre is quite small (audience will definitely notice no glass), and it is a comedy where the glass break is part of the humor.
 

sk8rsdad

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Another consideration to using breakaways is the cleanup after the gag. It can mess up the pacing of the show if it can't be dealt with easily, and comedies are all about maintaining a fast pace. Sometimes less is more.
 

WFair

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Houston, Texas, United States
I hear you and understand the hundreds of reasons that breakaway glass might not be the right solution in many productions. All of that is already considered and dealt with. Not my first rodeo...been a TD for 20+ years. Just looking for tips to make glass.
 

JD

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North Wales PA
How about the saran wrap, but with a pile of pre-broken sugar glass above the top; Wrap pulls out and shards fall through frame?
Yellowing or cloudiness would not matter as the appearance would be so brief. The whole thing should be fast enough to fool the eye.
 

WFair

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Houston, Texas, United States
Yes...that might do the trick. Thanks. My concern is that the closest audience is only about 5-8' away...so saran wrap might still look too fake (though I can probably get it tight enough in the mullions to appear rigid). Certainly cheaper than full sheets of sugar glass. I can easily add sound to the window for the breaking and I like the idea of some real fragments falling. I may play with this. There is time to do it and then still pull off a sugar glass window if the effect is not good enough.

That said...I am still curious if anyone on this forum has experience making sugar glass and then coating it to fight humidity/clouding? And has anyone tried Isomaltitol rather than sugar?
 

ruinexplorer

Sherpa
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Sorry, I've lived in one desert or another all my life.
 

AshleyB

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Apr 6, 2014
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Birmingham, AL
There is time to do it and then still pull off a sugar glass window if the effect is not good enough.
If the Isomaltitol is inexpensive enough, and you have the time, try a few small panes (both with and without the poly coating) and see what happens! Youtube it though, so we can all learn.


Southern Theatre Magazine did a fantastic article this past issue comparing the cost and labor involved in different methods of wood flooring (paint only vs ripped ply vs vinyl etc...). Detailed and informative. I wonder if they've done a similar one on glass effects. Might be worth checking out.
 
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