Thursday, July 21, 2011

When Failure Is The Only Option.

About 8 years ago I thought of building a new animated prop for my Halloween Party / Haunt. It was going to be your typical "Creature In A Crate" prop. I saw it on a website somewhere but not wanting to spend the $1500.00 price tag, I figured I would just build it myself. Now you have to remember, this was before You-Tube videos were around and the website only had a picture and a short description. So this was all trial and error, as most builds are, but lets just say I had a shit load of error. The build went like this, I needed it to be lite, so I could store it in my attic. It also couldn't be to big that it wouldn't fit through a door jamb. I started with ¼ inch Hardy Board for the shell of the crate, this is that brown backer board normally used as cabinet backing which is light weight and cheap to get. (This was my first mistake, great for cabinet backing, sucks for Halloween props). I made the box and screwed 1 x 2 rough sawn wood to go around the edges and in a criss cross pattern on the top and sides to give that “wooden crate look”. I put a hinged door in the front so I could get access to the mechanics inside. The door had a window with bars made from ¾ electrical conduit. I then made a small pallet, out of the same 1 x 2s I used for the edges, that was about 3 inches bigger then the crate on all four sides to fit under it. I ran heavy chain from the top four corners, using screw in I-bolts, to the bottom of the pallet, leaving some slack for the crate to bang around. This was to give the appearance that the monster inside was so crazy only chains could keep it tied down. But as I think about it now, it's ridiculous in real life, have you ever seen an animal shipped with chains holding the box down.( I guess it just looked cool), Anyway, I sprayed the whole thing with black, gray, and red spray paint to give it a old burnt dirty look. It did look nice and if I were smart I would have just stopped there and made it a static prop. (oh the money I would have saved) But I wanted it to shake, jump and rattle like a monster was inside.

I had an old 120v motor out of a floor standing belt sander that I wanted to use for the shacking. I made a a 6 diameter alum plate with a hole drilled 2 inches off center. I cut a slot into the bottom of the crate and had the alum plate stick through it. The idea was, when the motor spun the plate around, it would hit the top of the pallet and lift the whole crate up and bang it around violently, like a big cam. (This would be another mistake. You know the kind a horse power you need to lift a wooden box with the weight of motor and chains attached? Well neither did I and I still don't. But I bet a lot more then ¾ horse) The motor was hooked up to a Terror By Design prop controller and a dimmer switch to adjust the speed. OK, now for the moment of truth. I plugged in all in and hit the little red button on the controller and BAM. The plate spun around hitting the top of the pallet and STOPPED DEAD. The motor wasn't strong enough to lift the crate. Well after some brain storming I thought I would just lift the motor so that the plate doesn’t hit the pallet and will just vibrate the crate violently. I did that and hooked it all up, hit the red button and holly shit did this crate shack, jump, vibrate, and just go nuts. It looked great. But just as I was admiring my new creation, I saw the top start to come lose from the sides, and then one of the eye bolts ( that was holding the chains down) ripped out of the wood. With out that one chain, it moved off to the side of the pallet ripping the other 3 chains out making the crate totally flip on its side. The motor, now hanging upside down, rips out the wood and acts like a jackhammer and blows the rest of the crate apart. It stopped only after the motor ripped its own cord from its back. All this happened within 15 seconds. Almost all the screws ripped out the Hardy board and 1 x 2s, the wiring was a big tangled mess and all that was left, was a pile of scrap wood. I stared at it for about a minute, then walked out of my workshop and did not come back to clean up the destroyed prop till the next weekend. (No, that picture is not the prop. But thats almost what it looked like.)

So what did we learn here?

Sometimes cheap isn't always the best way to go.

If I would have used ½ plywood or ½ solid wood planks for the crate box is would have stayed together. Try to stay away from Hardy Board, Particle Board, MDF, OSB or anything like that. Solid wood, plywood or metal only.

I should have put inside corner bracing to keep it from racking. Anywhere you can put bracing is a good idea for any animated prop. Blocks of wood, angle alum, steal brackets are all good.

Should have used wood screws or even better, deck screws instead of drywall screws. They may cost more but there heads won't pop off under a load.

Instead of the screw in I-bolts for the chains, I should have used bolt through I-Bolts with a nut and oversized washer.

I should have used through bolts to mount the motor instead of screws. Just like the screw in I-bolts, there is alot less of a chance of pull through.

I could have skipped the motor all together and used a pneumatic piston to pop the crate around. A linear movement is a lot easier to control then a spinning movement. And in would have looked much more real.

And the biggest thing I should have done was to test it before I finished it. That would have saved me the most time and money. Always test your mechanism before you build. Be it a 4-bar lifter, a scissor reacher or a simple pop up, make sure it works. That way you can make changes before your to deep into it.

Good luck on your build.

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