We have about 75 fairly delicate stage lights (known as "instruments") that I have to hang, store and maintain. We have 2 different stages and we often move many of the instruments from one venue to the other. This had always been done in the past by hand-carrying them from the storage area to the stage, then back to the storage area, then to the other stage, etc. etc. etc. This was hard on the the people, the instruments and my patience, since I had to keep fixing them.
Another problem we always had was, oddly enough, lighting. When you're 18 feet up on a ladder or scaffolding, there's very little light up there to see what you're doing. (Ever notice how ceiling lights don't actually light the ceiling? I didn't either until I tried to work up there regularly.)
Then I had a bright idea (pun intended).
I designed and built a cart that would:
- Safely carry about 45 instruments
- Safely carry a ladder
- Provide locked tool storage
- Store lighting parts & accessories (gels, gobos, lamps, gel frames, etc)
- Provide work lighting overhead.
3 4x8 sheets 3/4" plywood
5 8' pieces 2" metallic conduit
10 2" hose clamps
4 8' 2x4s
2 300 watt halogen lights
4 locking swivel casters - 4 or 5 inch, 200 lb capacity or more
10 cheap bicycle hanger hooks
- 2" Hole saw
- Circular saw or table saw
- Hack saw or 2" tubing cutter
Decide on the size you need. I wanted to carry as many lights as I could using a frame based around 4x8 sheets of plywood. I considered using an empty all 2x4 frame, but I also wanted places to put a number of hooks to hang power cables, safety wires, bungees, etc. Using plywood allows more choices, and also lets you collect lots more dust..
My cart can safely carry about 7 Altmann ellipsoids on each pipe or about 10 el-cheapo PAR cans. With 5 pipes that gives my cart a carrying capacity of around 35-50 instruments, plus 15-20 clamp-on drop lights on the lengthwise 2x4 on top.
I used 5 pipes with a horizontal offset so that instruments hung on the upper pipes don't collide with lower ones. More details about that in a later step.
Build the base
I cut a 36"x96" piece of 3/4" plywood for the base.
Added 2x4 bracing standing on edge around the top outside of the base. This serves to enclose the bottom with a 3-1/2" lip so things don't roll off and also adds rigidity to the base.
Mounted locking 4" swivel casters at the corners.
Build the ends
I cut the end pieces to be 33" wide at the bottom (so they fit snugly inside the 2x4 bracing around the base section). They go straight up for about 24" then angle inwards to about 12" wide at the top. You could just make it a plain rectangle, but this shape allows for:
- An angle to hold a ladder more securely
- Center of gravity more centered.
- Narrower profile
Mount end pieces on the base
- Screwed through the plywood end piece into the 2x4 bracing around the base.
Add diagonal bracing
- Added mitered pieces of 2x4 to help brace the end pieces.
Add end-to-end stretcher
- Fastened a full-length "stretcher" between the tops of the ends in order to add rigidity. This piece also serves as a place to mount work lights and to clamp drop lights (We use a lot of clamp-on drop lights for safety lighting back stage.)
Cut & mount the pipes
- Cut 2" holes on the ends so the bottom pipes will be at least 24" above the base so that lights (EXCUSE ME, I mean INSTRUMENTS) have a few inches clearance from the base so they won't bounce off items stored on the base.
- Measure the length from outside of the end pieces and add 2"
- Insert pipes in the holes
- Use hose clamps on the pipes outside of the ends to prevent the pipes sliding. (Or you could drill the pipes and use pins.)
Add work lights
Mount halogen lights on top of ends of stretcher bar and wire in. I installed a switch at one end of the cart and gave it it's own 50' power cable which also powered an on-board outlet for testing lights. (This isn't shown as I took these pics before then.)
Install bicycle hooks on the ends, both inside and outside, for storing safety cables, empty gel frames, tools, etc.
Install one on each end such that you can hang a ladder on them and take it with you on the cart.
I built a box with a hinged top and a hasp so I could padlock it, then attached it to the outside fo one end of the cart. People who don't know better are prone to handling the oddly-shaped replacement lamps. Unfortunately this almost guarantees that your nice new $35 lamp will literally explode when powered on - and of course it'll be in the middle of a performance and THAT light will be hanging over the audience. Had that happen more than a couple of times until I started locking up the spare bulbs.