One of the many ways you can fabricate a piece of sheet metal is to stretch it. Despite its seemingly tough nature, metal is a lot more malleable than people realize. A stiff sheet of steel can easily become a bendable, constantly moving item with the right fabrication processes. If you're looking at stretching sheet metal for the first time for a new project, you should be aware of what it can do, both to the metal you're stretching and the metal around it.
It Will Get Thinner
Stretching methods include using a mallet to pound the metal and a roller to change the thickness of the metal. These methods work by essentially shoving metal molecules out of the way of the mallet or roller, thus elongating that section of the metal. As a result, the area under the roller or mallet will become thinner. This can pose a problem if you try to use too much force or keep stretching the metal for too long, as overly thin metal can become too fragile for use. You'll have to ensure that the entire piece that you intend to use is the thickness you want, which means more rolling and more mallet use.
One common issue is fracturing when stretching has gone too far. Necking is a warning sign that a fracture is possible. A neck is a line of metal that's become super thin due to the stretching process, and fractures often occur in these spots. When you look for a sheet metal fabrication shop, you can ask them about how they avoid necks, fractures, and metal tears during the process.
It May Curve
As you stretch and thin one section of the metal, other sections around that section may start to curve. This is due to the metal right by the section under the roller or mallet moving away from that spot while the rest of the metal doesn't move. The result is a curve, which may be what you were aiming for in the first place. However, if it isn't what you want, you'll need the rest of the metal stretched as well. As you can see, stretching ends up being a multipart process. However, the results are worth it.
Stretching isn't the only fabrication method, but it is a good one for when you want a longer piece of metal, or one with a specific type of curve (such as the one mentioned previously, created from thinning another section of metal). Speak to the fabrication shop about which method they use to stretch the metal and what safeguards they have in place to ensure they don't thin it too much. A sheet metal fabrication company can provide more information.
Share