There are hundreds of sheet metal fabrication techniques, but if you’re just starting out, here are six basic techniques that everyone who’s new to the metal fabrication process.
1. Cutting Metal
Every fabrication process begins with sheet metal cutting. The cutting method used depends on the thickness of the metal and the project’s specifications. Several ways you could cut metal for your project include:
- Water jet – A waterjet is a tool used to cut sheet metal using an extremely high-powered stream of water. By channeling water through a narrow nozzle at high pressure, we can cut through many thicknesses of sheet metal.
- Torching – A cutting torch is a powerful tool that uses a hot flame to cut sheet metal that can be oxidized, such as steel sheet metal.
- Shearing – Here at Eckstrom Industries Inc., we shear metal using two offset blades, similar to large scissors. The sheet metal is held flat and the top blade is brought down onto the surface, pushing the metal down onto the bottom blade. We also have a variety of smaller, hand shears which can be used to manually cut smaller and thinner pieces of sheet metal. Hand shears are the way to go for smaller projects!
- Sawing – We use circular saws and bandsaws to cut metal sheets that are too thick to be cut via shearing, water jet, or torch. Sawing is a longer and more intensive process, which is why it’s reserved for especially thick material.
2. Bending Metal
Once your metal is cut, the next step for most sheet metal fabrication projects is to bend metal into the desired shape. Two ways to do this are:
- Metal brake – This involves placing one end of the sheet metal inside a gate, with the other end being clamped in place with a bar. The portion of the metal stuck inside the gate gets lifted, while the part which is under the bar stays put. The metal brake creates the necessary bends in the metal. Here at Eckstrom Industries Inc., this is how we do the majority of our bending work.
- Form bending – This is a more hands-on approach to metal bending and is done by bending sheet metal over an edge or shape with blows from a hammer.
3. Welding Metal
When it comes to assembly, there are a number of welding options available to you to put metal together. Which method you use is determined by the kind of metal, the thickness of the material, and your welding equipment. Some of the most common welding processes include:
- MIG welding – This is an arc welding process where a continuous wire electrode is fed through your welding gun and into the weld pool. To protect the pool from contamination, a shielding gas is also fed through your gun.
- TIG welding – This welding method uses an electric arc and infusible tungsten-based electrode to generate welds. The TIG welding process is ideal for sheet metals that are up to 8-10mm thick.
- Laser welding – This process to put metal togther uses a high-powered, solid-state, laser resonator (like a disc laser) to melt the metal. Laser welding enables a fabrication shop to generate consistent, high-quality welds.
4. Shrinking Metal
Some fabrication projects require shrinking metal in order to smooth out dents or create the desired shape. Three sheet metal shrinking methods are:
- Heat shrinking – A torch is used to heat the dented section of metal, this overstretches the metal, causing it to shrink once it cools.
- Tucking metal – This uses a planishing hammer and tucking fork to tuck the edges of the sheet metal and hammer them into place.
- Shrinker machines – As opposed to the two previous hands-on approaches to sheet metal shrinking, shrinker machines can be used to automate the shrinking process. This machine has jaws that grab the sheet metal and force it together, shrinking it into the desired shape.
5. Stretching Metal
The opposite of shrinking, sometimes it’s necessary to stretch sheet metal. There are several ways to complete this basic sheet metal fabrication technique and three of them are:
- Stretcher machines – The opposite of the shrinker machine, a stretcher machine has powerful jaws that seize each end of your piece of sheet metal and slowly stretch it to the desired size.
- English wheel – This machine is based on the traditional anvil and stretches metal by pressing it against a lower anvil and upper wheel. The English wheel can be used to smooth out imperfections and create compound curves.
- Hammer and anvil – This hands-on approach to sheet metal shrinking requires a hammer and an anvil (or another heavy-duty object). You place the metal on the anvil and repeatedly strike it with your hammer. This will slowly increase the surface area and cause the metal to stretch.
6. Finishing Metal
Once you’ve cut, stretched, shrank, and welded your metal, the final basic sheet metal fabrication step is to finish your project. Adding a finish to your metal will enable it to last longer and perform better. Three common finishing techniques are:
- Sandblasting – This involves shooting sand and other abrasives against your sheet metal at a high velocity. Sandblasting creates a matte texture on your sheet metal and is often used to prepare metal for coating.
- Buff polishing – This finish is created by using a cloth wheel to buff the surface of the metal. If you want your metal project to shine, then buff polishing is likely the technique for you.
- Metal plating/coating – Various coats can be applied to your project via chemical baths, which alter the substrate and improve the corrosion resistance and durability (as well as look) of your sheet metal project.
Looking For An Expert Sheet Metal Fabricator Near You?
For 80 years, Eckstrom Industries Inc. has been fabricating sheet metal for businesses around the Greater Seattle Area. Our decades of experience and proven track record have established us as leaders in the local fabrication industry.
If you need help with a sheet metal fabrication project, contact Eckstrom Industries Inc. today.