Electrical arc effects
Printed From: Community Theater Green Room
Category: Producing Theater
Forum Name: Lights and Sound
Forum Discription: Technical discussion
URL: http://www.communitytheater.org/forum/forum_posts.asp?TID=2681
Printed Date: 5/14/24 at 6:23pm
Software Version: Web Wiz Forums 8.05 - http://www.webwizforums.com
Topic: Electrical arc effects
Posted By: mikepatterson
Subject: Electrical arc effects
Date Posted: 9/20/07 at 12:24am
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Just posting a note to describe how I produced an electric arc effect. We just finished a run of One Flew Over The Cuckoo's Nest. A key part of the play involves a large "electrical control box" that is torn from the the floor and thrown in the climactic final scene. I wanted some arcing effects with popping and flashing to make it look good. Looked all over the 'net and couldn't find anything suitable, so I decided to make my own. What I came up with was a box about 12 inches deep, 32 inches high and 30 inches wide with a slanted hinged top (locked with a hasp and padlock to make it look like something the hospital staff didn't want the patients to access). Helpers built the box to my design, then cut rectangular "ventilation holes" in the sides and front, with expanded metal mesh screen behind them and trimmed the holes to give a neat appearance. Painted the whole thing "electric box gray". Then we cut a couple of 3" holes in the back side, and lined them up with matching holes in the wall the box was to be "mounted" to. Fastened a bunch of multi-colored wires inside the box and the wall hanging out the holes. (These were the wires that were "torn out" when the box is ripped from the floor.) Now comes the fun part - Screwed a screw eye inside the box and another on the back side of the set wall. Drilled a 1/2" hole in the back side of the box. Strung a 36" piece of 2-wire electrical cord through the 1/2" hole and put a knot in it inside the box so that it wouldn't pull completely out of the box. Other end of the wire goes into the set wall and the wire ends are stripped about 1 inch, passed through the eye behind the set wall, and twisted together. Back inside the box, the free end of the wire has a screw link attached (like this: http://www.rocknrescue.com/acatalog/Oval-Screw-Links.html) Then I got about 12 pull-string "booby trap" fireworks like these: http://cgi.ebay.com/PULL-STRING-POPS-BOOBY-TRAPS-FUN-GAG-PRANK-JOKE_W0QQitemZ130127596136QQcmdZViewItem (Each of these has two strings, when pulled apart, they produce a nice loud "pop", a flash of light, and a puff of smoke.) I tied one end of all twelve together and then tied several pieces of kite twine to the other string ends to make effectively make them a variety of lengths. The free ends were then all tied together. If you were to pull on the opposite ends of this tied-together bunch of poppers, they would pop at different times because of the different lengths. And that's what I did, I fastened one end of the bunch to the screw link and the other to the screw eye inside the box, carefully arranging the knot in the electrical cord so that the total length of the wire -inside the box- was short enough so that when the wire was pulled it would pull all the strings. When the last popper went off, the knot would hit the sides of 1/2" hole and now the twisted wires behind the set wall would be pulled apart, leaving only more wires coming into view of the audience, no tell-tale strings. The total effect was great, as the box was pulled away from the wall it got about 12 inches out before the "arcing" started, which then continued for about another 24" as the box was pulled further out. The popping sounded realistic, the flashes could be seen through the "ventilation holes", and even the smoke looked good. Best thing was it was repeatable. Before every show I spent about 15 minutes tying a new bunch of poppers together, setting the box in place, running all the colored wires through the 3" holes so they'd be pulled out, and setting it all up inside the box through the hinged top, which was then padlocked. Worked like a charm every performance for 11 nights and cost about $5 total in parts. The satisfaction of coming up with something like this is the kind of stuff that makes the sweat and hard work worthwhile. Mike |
Replies:
Posted By: Gaafa
Date Posted: 9/20/07 at 8:58pm
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MikeO what a little Rippah! Much more effective than the 'LeMatre' sparking robotics pyro effect machine. Far easier & safer then ballons filled with smoke exploded by loading black powder & alluminium can filings, wraped in fiol around a hot wire & shooting sparks. Bewdy 'n g'donya mate!  ------------- Joe Western Gondawandaland turn right @ Perth. Hear the light & see the sound. Toi Toi Toi Chookas {{"chook [chicken] it is"} May you always play to a full house} |