Hey! We are now on the third post regarding steel fabricators’ tools and techniques. On the first two posts we talked about metal shaping and metal cutting. Now we will talk about the third part – metal shrinking. Let’s get this done!
What is shrinking metal?
It is the process where in we used to remove small dents in which the direct damage is not too severely torn or stretched, or the work-hardness of the buckles is not too severe. Examples are hail damage and other small dents.
The operation is used when:
Techniques and Tools
Tucking Metal
It is one of the earliest methods of shrinking metal. In this method, fabricators are bunching the metal literally, together by forcing it between a crevice with a spade hammer or by folding the metal over at the edges with a tucking fork.
This method has been used to form some of the earliest most valuable sports cars. A good hammer and a wooden stump with cleverly placed cuts and crevices formed can really work wonders!
Shrinker
It is a lever-operated tool (either by hand or foot). It has moving textured jaws that grasp sheet metal from the top and the bottom and force it together tightly. This method is much more precise than tucking with a hammer and form, but moves the metal much slower. With this, you can carefully work particular areas to shrink them as desired. The tool leaves minimal marring on the metal, which most can be smoothed or removed out with a sanding file or disc.
Heat Shrinking
This takes a lot of practice to master. The basic idea is that you will heat up an overstretched area with a torch, almost red hot and them as the area cools it shrinks. The amount or type of stretched metal or damage will determine how you shrink or smooth the area out. A hammer and dolly is needed for the area or quench with a wet rag of compressed air to get the desired shrink. For an alternative method, there are shrinking discs that are available on the market which are attached to an angle grinder that use friction to create the heat. These are more precise and avoid using a torch or flame to heat and shrink the metal.
Stretching Metal
Hammer and Dolly
This is the most basic, traditional way to stretch metal. Through this method, you are firmly holding an object behind the metal and hit the other side with a hammer. This forces the metal to be compressed and ultimately stretched. Metal can also be stretched in a similar method by using a sandbag and pastic mallets to quickly stretch metal and make shapes.
Stretcher
This is the very opposite of the shrinker we talked above. This is a mathematically operated tool that puts the metal between two flat textured jaws and pulls the metal apart in a slowly manner each time the lever or foot pedal is pressed. The shrinker and stretcher together are must have items for anyone doing the sheet metal fabrication.
English Wheel
This method is quite similar in using a hammer and dolly. The metal is placed between a large, flat-faced upper wheel and a lower “anvil” that has a radius to the face. The lower wheel is then screwed up to pinch the metal between the two wheels and the metal is rolled back and forth slowly stretching the flat metal over the curved lower wheel. This method stretches the panel to create a uniform crown. English wheel can also be used to smooth out imperfections in the metal caused by using a plastic mallet and sandbag as described above.
PART 4 here!
Looking for steel fabricators in the Philippines? Check out TKL Hardware and Construction now!
What is shrinking metal?
It is the process where in we used to remove small dents in which the direct damage is not too severely torn or stretched, or the work-hardness of the buckles is not too severe. Examples are hail damage and other small dents.
The operation is used when:
- It is determined that the cause of heat is necessary
- Dents are located behind the inner construction that hinders regular bumping
- It is necessary to reduce the size of the dent
- It is necessary to avoid removal of certain parts
Techniques and Tools
Tucking Metal
It is one of the earliest methods of shrinking metal. In this method, fabricators are bunching the metal literally, together by forcing it between a crevice with a spade hammer or by folding the metal over at the edges with a tucking fork.
This method has been used to form some of the earliest most valuable sports cars. A good hammer and a wooden stump with cleverly placed cuts and crevices formed can really work wonders!
Shrinker
It is a lever-operated tool (either by hand or foot). It has moving textured jaws that grasp sheet metal from the top and the bottom and force it together tightly. This method is much more precise than tucking with a hammer and form, but moves the metal much slower. With this, you can carefully work particular areas to shrink them as desired. The tool leaves minimal marring on the metal, which most can be smoothed or removed out with a sanding file or disc.
Heat Shrinking
This takes a lot of practice to master. The basic idea is that you will heat up an overstretched area with a torch, almost red hot and them as the area cools it shrinks. The amount or type of stretched metal or damage will determine how you shrink or smooth the area out. A hammer and dolly is needed for the area or quench with a wet rag of compressed air to get the desired shrink. For an alternative method, there are shrinking discs that are available on the market which are attached to an angle grinder that use friction to create the heat. These are more precise and avoid using a torch or flame to heat and shrink the metal.
Stretching Metal
Hammer and Dolly
This is the most basic, traditional way to stretch metal. Through this method, you are firmly holding an object behind the metal and hit the other side with a hammer. This forces the metal to be compressed and ultimately stretched. Metal can also be stretched in a similar method by using a sandbag and pastic mallets to quickly stretch metal and make shapes.
Stretcher
This is the very opposite of the shrinker we talked above. This is a mathematically operated tool that puts the metal between two flat textured jaws and pulls the metal apart in a slowly manner each time the lever or foot pedal is pressed. The shrinker and stretcher together are must have items for anyone doing the sheet metal fabrication.
English Wheel
This method is quite similar in using a hammer and dolly. The metal is placed between a large, flat-faced upper wheel and a lower “anvil” that has a radius to the face. The lower wheel is then screwed up to pinch the metal between the two wheels and the metal is rolled back and forth slowly stretching the flat metal over the curved lower wheel. This method stretches the panel to create a uniform crown. English wheel can also be used to smooth out imperfections in the metal caused by using a plastic mallet and sandbag as described above.
PART 4 here!
Looking for steel fabricators in the Philippines? Check out TKL Hardware and Construction now!