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Flameproofing with Props
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Flameproofing with Props

by mtgerlach on Mon Nov 20, 2017 2:31 pm

Hey friends,

I am a prop maker working in a regional theater tied to a university, and as such have some regulations to conform to, and have a question about a process I'm being asked to use for flameproofing.
For our upcoming production of Wizard of Oz, I've built a straw broom that fires a fireball and a puff of sparkle-y flame, using flash cotton, flash paper, and a bit of magnesum powder. This is all mounted at the end of a length of dowel, and wrapped out with a broom corn mat. The request was to also make the broom sparkle with lights (think burning embers left in the broom), so I wired in some LED sequins, driven by a Gemma board and a small LiPo battery. Then the inspectors came.
Despite having flame-proofed the whole shebang before wiring, they insist that I need to do so again. I also found that the flameproofing treatment we used in the first place had a tendency to sit on top of the broom fibers and came off as I was wiring in the LEDs. So i've been asked to soak the whole thing in a solution of basically Borax and Boric Acid, to get the fibers of the broom to soak up the solution.

I will of course remove the battery, but i'm still worried about the board and components if they're soaking in anything harsher than water. Do I need to be concerned? Are there precautions i can take that don't involve removing the board and rewiring?

mtgerlach
 
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Re: Flameproofing with Props

by franklin97355 on Mon Nov 20, 2017 4:04 pm

We have never tested for this but, perhaps someone on the forums has experience on purpose or otherwise.

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Re: Flameproofing with Props

by adafruit_support_mike on Tue Nov 21, 2017 2:50 am

I wouldn't expect any physical damage from borax or boric acid, though all the solder joints will probably turn black.

I'd be a bit concerned about residue left behind after they dry though. They're both weakly conductive, and you could end up with all sorts of unexpected parasitic current between components. I doubt that would have much effect on the LEDs, though brushing off any dust with a paintbrush would probably be a good idea. The microcontroller could get flaky though.

Personally, I'd remove the microcontroller before soaking.

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Re: Flameproofing with Props

by mtgerlach on Tue Nov 21, 2017 10:55 am

Thanks for the advice. I think I can get away with only soaking the tips of the broom, so something like 8 or 9 inches from the controller. The rig for the pyro is right near the end of the broom, so theres really only 2 or three inches that need the fireproofing. So there are a few LEDs that will be hit, but i've definitely given them all a good coat of clear nail polish already. Think that would be enough?

mtgerlach
 
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Re: Flameproofing with Props

by franklin97355 on Tue Nov 21, 2017 3:40 pm

a good coat of clear nail polish
Should be enough.

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