STEP 4. Selecting Materials

Materials are a major part of your project. Leave lots of time for studies in this area. Understanding the advantages and disadvantages of differing materials and the properties associated with varying shapes is an integral part of this material selection process. Figure 1.8 illustrates cross sections of material commonly used on trailers along with a few not so common shapes. Shown are some of the choices you have for framework materials.

Basic and generalized ideas of materials are something worth considering before you begin drawing. You may already know that steel is best for the frame and wood is best for the floor; but, an aluminum diamond plate may also sound pretty good. However, if aluminum is not available to you, (either physically or financially) your choice may still be wood. Whatever you select, just be sure the material is right for the job.

Calculations can help with knowing if the material you’ve chosen is strong enough. Volume 2 discusses calculations used for choosing an optimum shape for a given load and elaborates on properties important to understand. Your final choice is generally a co-ordination of requirements, such as load pick-up points, cargo dimensions, strength and connection methods. Be prepared to use different size or different gauger different places throughout the trailer. For instance, fenders do not require the mass of material the axle requires. Building a trailer from one size such material is apt to produce undesirable results. Using material big enough to carry the load without overdoing it is efficient weight wise and can even be better space wise. While this approach may appear obvious to some, the concept of variable sizing is important to understand.

Scrap steel narrows the options and may force a result you didn’t desire. Building with “what’s good and heavy” also adds weight fast and a trailer too massive may result; thus imprecise approaches are often detrimental.

The materials from which a trailer is made determine its entire character. And although the selection process can seem tedious and exhausting, you will be well rewarded for your patience and careful selection of each piece.