Sheetmetal Floor Pan Sizes: Get It Right

Sheet metal for floor pans is available in various thicknesses, typically ranging from 14 to 18 gauge. The most commonly recommended thickness for floor pans is 18-gauge metal, which offers a balance between strength and workability. Thicker metal, such as 14 or 16-gauge, can provide extra strength and stiffness but may require more effort to form and install. When replacing floor pans, it is essential to consider the original thickness of the metal, the desired level of durability, and the ease of fabrication and installation.

Sheet metal gauge for floor pans

The ideal sheet metal gauge for floor pans depends on the specific application and preferences. The most commonly recommended gauges for floor pans are 16-gauge and 18-gauge steel.

Some people prefer 14-gauge steel for extra strength and stiffness, but it requires more work to form. 16-gauge steel is considered slightly thicker than most stock panels but may be comparable to earlier factory sheet metal. It provides more strength and stiffness than 18-gauge steel.

18-gauge steel is a popular choice for aftermarket floor pans and is considered adequate in strength by many. It is thinner and easier to work with than 16-gauge or 14-gauge steel. However, some find it very tricky to weld with 18-gauge steel, and thinner gauges may be more challenging to weld.

For patch work on floor pans, it is recommended to use at least 18-gauge steel or thicker. Thinner gauges, like 20-gauge or 22-gauge, may be too difficult to weld and are not recommended for floor pans.

When replacing or repairing floor pans, it is important to consider the specific vehicle make and model, as well as the desired level of strength and ease of fabrication.

Sheet metal thickness

When repairing or restoring old cars, it is common to have to deal with rusty floor pans. While sometimes patch work will do, often the rusty floor pans will need to be completely replaced. This can be difficult and expensive, especially for rare vehicles. One way to save money is to fabricate the floor pans in-house. This can be done using a sheet of 16-gauge steel and some hand tools.

The thickness of sheet metal is indicated by its "gauge". Lower gauge numbers indicate a thicker metal sheet, while higher gauge numbers refer to a thinner sheet. The standard sheet metal gauge range begins at 30 (thinner) and goes down to 7 (thicker). However, the actual thickness and corresponding gauge will differ depending on the type of metal. For example, a sheet of 30-gauge standard steel measures 0.012 inches, while 30-gauge galvanized steel is 0.0157 inches, and 30-gauge aluminium is 0.01 inches.

There are several different gauge systems used today, with specific gauge designations for specific metal types. For instance, in one gauge system, 18-gauge steel measures 0.0478 inches thick, but 18-gauge aluminium is 0.0403 inches thick. Because of these varying thicknesses, a gauge chart should be used to ensure the metal meets the required dimensions.

The gauge system likely originated from the British wire industry before the standard and metric measurement systems were widely adopted. Gauges were used to describe the diameter of metal wire being drawn, and this has continued as a prevalent method of designating the thickness of wire and sheet metal.

Floor pan replacement

The first step is to assess the damage and determine the extent of the replacement needed. If only small areas are affected, patching may be sufficient. However, if the damage is widespread or the floor pan is severely rusted or crumpled, a full replacement is usually necessary. In some cases, you may need to fabricate the replacement floor pan yourself, especially for rare or vintage vehicles where finding matching parts can be difficult and expensive.

To fabricate a basic floor pan patch, you will need a range of tools, including a welder, body hammer, cutting wheel, wide sheet metal pliers, drill and bits, chisels, and a die grinder. You will also need a sheet of metal, typically 16-gauge steel, which can be purchased from a local supply house. The size of the sheet metal will depend on the vehicle and the extent of the replacement, but a full sheet typically measures 4x8 feet or 4x10 feet, providing ample material for the project and potential leftovers for future repairs.

When creating replacement panels, it is recommended to make the panel first and then cut away the damaged metal. This ensures that you only remove what is necessary and that the new panel matches the cut-out section perfectly. You can use cardboard to create a template, marking and cutting it to match the original floor pan shape. Transfer this pattern to the flat sheet metal and cut it out, adding any necessary flanges or ribs to match the original design.

The installation process involves trimming and fitting the new floor pan, ensuring a precise match. It is important to cut on the small side and gradually trim as needed, as it is easier to cut away more than to add back metal. Floor pans are forgiving, allowing for minor mistakes without ruining the entire panel. Practice on scrap metal before working on your vehicle to improve your welding and fabrication skills.

Sheet metal fabrication tools

Sheet metal fabrication is a process that involves cutting, bending, and assembling metal sheets to create structures or products. Here are the tools that can be used for sheet metal fabrication:

Heavy Equipment for Fabrication

For larger parts and projects, heavy equipment is required for sheet metal fabrication. Some of the commonly used equipment includes:

• Sheet Metal Brakes: These machines are used for forming angles and bends in sheet metal. They come in various sizes and capacities, such as the Eastwood 12-inch Box and Pan Sheet Metal Brake or the larger 48-inch version.
• Tubing Benders: These tools are used to create brackets, holders, and other tubular shapes. They can be manual or hydraulic, like the Eastwood Pro Former Tubing Bender.
• Bead Rollers: Bead rollers are used to create strong lines and bends in sheet metal. They add strength and rigidity to projects. The Eastwood brand offers various models, including the Elite 8" Heavy-Duty Bead Roller.
• English Wheels: English wheels are used for forming curves and smooth surfaces in sheet metal. They are often used for automotive panel fabrication and general metal shaping.
• Planishing Hammers: These tools are used for light metal bending and finishing work, providing a smooth and flat surface to the sheet metal.

Metal Fabrication Hand Tools

For smaller jobs and intricate details, hand tools offer precision and portability. Some common hand tools for sheet metal fabrication include:

• Metal Cutters: Bench shears, hand shears, mini saws, and tin snips are used to cut metal sheets and create precise shapes.
• Metal Forming Mallets: Mallets, hammers, and sandbags are used to manually shape and form metal sheets. They can be used to create unique shapes or fine-tune larger projects.
• Grinders and Sanders: Bench grinders and sanders are used to smooth and shape metal surfaces, removing burrs and creating a uniform finish.
• Welding Equipment: Welding machines and accessories, such as clamps and pliers, are essential for joining metal pieces together.
• Layout and Marking Tools: Tools like angle finders, levels, radius gauges, and stencils help in measuring, marking, and laying out the sheet metal before cutting or bending.

Additional Tools

Depending on the specific requirements of a project, additional tools may be needed. These can include:

• Slip Rolls: Slip rolls are used to create curved or cylindrical shapes from sheet metal. They are often used for fabricating tubes or rounded panels.
• Shrinkers and Stretchers: These tools are used to shrink or stretch metal sheets to form complex shapes. They can be manual or hydraulic, depending on the application.
• Drill Presses and Bits: Drill presses and various drill bits are used to create holes and fastenings in the sheet metal.
• Plasma Cutters: Plasma cutters use a high-temperature plasma arc to cut through metal with precision and speed. They are often used for intricate shapes and curves.

The specific tools required for sheet metal fabrication can vary depending on the project's complexity and the fabricator's preferences. It is essential to have a range of equipment to work with, allowing for flexibility and precision in creating floor pans and other sheet metal projects.

Sheet metal suppliers

Sheet metal is a flat rolled product that comes in coils and is formed to be thin and flat to cover large areas. It is easy to cut into any size or shape and is used in a variety of industries for repairs and maintenance. Sheet metal is typically less than 3/16" thick and is measured in gauges, while plate metal is thicker and measured in inches.

There are several sheet metal suppliers that offer a range of metal types and sizes. Metal Supermarkets is a supplier that offers cut-to-size metal sheets with no need to buy full lengths. They offer a variety of metal types including brass, aluminium, anodized aluminium, and stainless steel. Metals Depot is another supplier that provides over 50,000 shapes, sizes, types, and lengths of metal with wholesale prices and no minimum orders. They also offer cut-to-size services and deliver worldwide.

When it comes to floor pans, the size and thickness of the sheet metal can vary depending on the specific application and vehicle. For example, a 1941 Lincoln Continental Cabriolet used a sheet of 16-gauge steel to fabricate replacement floor pans. The full sheet size was 4x8 feet or 4x10 feet, providing plenty of material for the project and leftovers for other applications.

In addition to sheet metal suppliers, local supply houses can also be a source for sheet metal. It is always recommended to have the proper tools and safety equipment when working with sheet metal and to practice on scrap metal before tackling a project on your vehicle.

Frequently asked questions