If you pick up a book on how to build magic, they quite often refer to building the bottom of the base out of sheet metal. One can immediately see the advantage of using sheet metal for the bottom of any base. By using sheet metal you immediately eliminate inches from your trick. The problem with this description is sheet metal takes on so many forms. I know the first time I read this; I was a bit confused what sheet metal really was. When you call a sheet metal distributor to ask about purchasing sheet metal you get a variety of questions: What type of metal do you need? What gauge do you need? Would you like hot rolled or cold rolled?
You have to understand the word sheet metal is a generic term- it is like asking for Kleenex at the store- they will show you an aisle of facial tissues. In this article I hope to give you some basic understanding of what sheet metal is.
In order to build with sheet metal you should understand a few basics about the material. First of all sheet metal can mean many things. When you go to buy sheet metal, it definitely helps to have a basic understanding of what it is and how to intelligently ask for what you need.
Sheet metal is metal formed by an industrial process into thin, flat pieces. It is one of the fundamental forms used in metalworking and it can be cut and bent into a variety of shapes.
The thickness of sheet metal is commonly specified by gauge. The larger the gauge number, the thinner the metal. Commonly used steel sheet metal ranges from 30 gauge- the thinnest, to about 8 gauge- the thickest. Gauge differs between ferrous (iron based) metals and nonferrous metals such as aluminum or copper. For most of my builds, I use an iron based metal unless weight is a major concern. The ferrous materials usually cost less and are easier to work with especially if you need to tack-weld or stretch long distances without buckle.
For the purpose of this article we will talk about three commonly used sheet metals in illusion building. These metals are cold rolled, galvanized, and aluminum sheet metal. Yes there are countless other sheet metals we could cover, but these are the three most common sheet metals I use in my shop.
Usually I’ll ask for cold-rolled if I’m building an illusion base between 24 and 16gauge depending on the span of the base. I wish I could tell you a good rule of thumb however this will just take some experimenting. In my shop, my equipment can only cut 16gauge or higher and bending any sheet metal beyond 14gauge without a pneumatic press gets very difficult. And, the weight can really add up fast at this point.
Galvanized sheet-metal is the most common metal used for HV AC ductwork. It’s a good metal to work with, however, I have found some difficulties. If I am adhering fabric to it, sometimes the glues don’t seem to hold as well. The other consideration is if you are welding galvanized steel, it can quite often emit poisonous gases. It’s important to be aware of this and work in a well-ventilated area with a welding hood or exhaust system above you.
Aluminum sheets are much lighter than steel, however the costs will be significantly higher. Aluminum also can only be welded with a TIG welder and with anything above 12 gauge, it is really impractical to weld. However aluminum is your best choice for any metal that would be exposed to the audience such as trim or blades. It is by far my favorite material to build blades for illusions- it is easy to drill and shape. And if properly done you can put a beautiful finish on it.
Where to buy sheet-metal
If you have a small one time project and you just need a small sheet, we’ll say less than 2′ x 2′, you can buy this at any of the big box home improvement stores. Usually you will find the sheet in the hardware section somewhere around the fasteners and nails. However this is not how you should buy sheet metal for a large or ongoing project. In your area you should be able to find a metal distributor. The big box stores markup metal extravagantly. Metal is much cheaper to buy from the distributor but you must keep a few things in mind. Typically they will cut the metal for you if you don’t have a way to cut metal yourself. There will be a cut fee, but that’s ok, it is much cheaper than purchasing a sheet-metal sheer. Usually a distributor will cut cold-rolled and aluminum, however, if you are buying galvanized quite often you will need to buy an entire sheet of metal. Check with your local metal distributors to find out what their policies are.
Another resource if you don’t have a sheet metal sheer or a distributor with one, you can check with a local sheet metal workshop. They will have all the equipment there and can supply the metal for your project. At the sheet metal shop you will also find a staff with a great working knowledge of sheet metal to help you out with your project. Just keep in mind that their time is valuable, and they will charge accordingly. Good luck with your next sheet metal project.