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The Nuts and Bolts of Building Materials

A pure electronics project might just consist of a breadboard containing components and wires. In most cases, though, you’ll also want to create some sort of container or chassis to hold the project. For example, if you build a simple radio, you might put the guts of it in a box and drill holes to place the dials and speaker. You can buy ready-made boxes or other containers and make them work for your project. You can also build your own out of various materials.

Plastic

ABS (please don’t ask what this acronym means; we could tell you, but you couldn’t pronounce it) plastic boxes are available from most electronics suppliers. These are lightweight, sturdy, waterproof, and handy for housing your gadgets. We use a plastic box in "Controlling a Go-Kart, Infrared Style" project to house a remote control. The plus with plastic boxes is that components such as switches are designed to be mounted on boxes or panels with thin walls. Therefore, mounting these components on these plastic boxes is often easier than on wooden boxes. The downside is that cutting clean openings in plastic is harder than in wood — for example, to insert speakers.

Wood

We like to use wooden boxes to house many of our projects because, well, they look nice. We found simple, unfinished wooden boxes at a national craft supply superstore (Michaels), but any craft store probably stocks them. Wood is also easier to drill and cut than plastic; however, you’ll often find that the wall of the box is 1⁄4" thick, which makes mounting components such as switches more complicated. In Chapter 4, we provide some advice on how to handle mounting components on wood.

Build it yourself

If you don’t like to buy ready-made containers, you can make your own boxes from wood or plastic. You can easily find lots of books that tell you how to make all sorts of things from wood, so we don’t get into that. To start, you might check out the Woodbox.com Web site and click the Wooden Box Making link for a good overview. If you want to make your own boxes or build fancier shapes out of plastic, such as a model car, to mount your electronics.

This article is a nice introduction to making custom plastic boxes for electronics projects. For some projects, you will mount boxes on a base or sandwich them between two sheets of materials. We used sheets of PVC and plywood in our projects. Quarter-inch or 6 mm thickness is a good bet for a strong base. You can use thinner sheets — for example, 1⁄8" or 3 mm — when you don’t need structural strength. Rigid, expanded PVC is often used instead of other plastics because it resists the buildup of electric charges, which might cause electrostatic discharge, which can zap your electronics components.

Robot supply houses, such as Solarbotics (www.solarbotics.com) or Budget Robotics (www.budgetrobotics.com), carry PVC sheeting. At Solarbotics, this material is sold under the product name Sintra. You can find plastics suppliers that sell rigid expanded PVC in 4' x 8' sheets, which is economical if you plan to use a lot of it.

Holding it all together

Sticking materials together to form boxes or whatever can be done in a few different ways. You can attach many different types of materials together with glue. Look for a glue called contact cement. This can bind a wealth of materials, including metal, plastic, rubber, and wood.To mount components such as speakers, you need screws and nuts. The parts lists in our project chapters tell you what size screws and nuts to get; we’re betting you have some of these in that leftover cake tin in your garage gathering dust, but you can buy what you need for pennies in any hardware store. We find that 6-32 screws fit many mounting holes.

Holding down wires

Wire clips are very useful for organizing wires that you affix to your project container. These generally have an adhesive backing on the base that you use to attach them to a surface. Then you slip the wires into the clip, and they are nicely held in place. (We use RadioShack part #287-1668.) Cable ties can also be useful when you want to run wires along something without a flat surface, like a wooden dowel.