The tubes can be bent with different techniques depending on the use you want to make of them. The problem is figuring out where and how much to bend the pipe. While many benders come with instructions for taking measurements correctly, they are often intricately written and involve a knowledge of mathematics that discourages most users. You can't do without mathematics, but you can make a simplified calculation for the bend angle so that the only knowledge you need is arithmetic. The method described below is not easy, but with a little practice you will master it without problems.
Steps
Method 1 of 3: Choose the bender
Step 1. Choose the right tool for your needs
There are six main methods of bending, and each is suitable for one type of pipe.
- Press bending, also called incremental bending, is typically used to bend metal angles, such as electrical conduits. This technique requires the piece to be held at both ends and the tip bends the metal in the middle. The fold tends to deform into an oval both inside and outside the tube.
- Matrix bending is used for handrails, ornamental hardware, car frames, roll bars, trailers, or larger pipes. Two dies are used: one fixed and one rotating to perform the fold. This technique is used when the pipe must have an optimal finish and a constant diameter along its entire length.
- Mandrel bending is used to make series or artisanal mufflers, pipes for dairies, heat exchangers. In addition to the two dies used in the prior art, a flexible support is used which bends with the tube to ensure that the interior of the piece does not deform.
- Induction bending uses an electric coil to heat the area to be bent before folding with dies similar to those used in previous techniques. The metal is immediately cooled in water to temper it. Tighter curves can be achieved with this technique.
- Cold bending is used to make less angled bends, such as curtain supports, barbecue grills, battery hoops. The technique is also used in the construction industry. Three dies are used, each mounted on its support, to bend the tube. The tool pushes the bent tube down to continue bending. The dies are placed in the shape of a triangle, which is why this technique is sometimes referred to as a pyramid folding.
- Hot bending, on the other hand, is mainly used in repairs. The metal is heated at the point to be bent to soften it.
Method 2 of 3: Do a right angle bend
Step 1. Make a 90 degree bend on a test piece
This piece will serve you as a champion in the future and will allow you to understand how much force to apply.
To check the fold angle use a square, overlapping the outer edge of the fold over the corner. Both ends of the tube should be parallel to the sides of the square
Step 2. Find the start of the curvature
You should feel a small unevenness where the crease begins and ends.
Step 3. Mark the ends of the bend with a permanent marker
Mark the entire circumference of the pipe.
Step 4. Lay the tube back on the square to measure the length of the bend
Note the size of the marks made earlier. They should be at the same distance as the center of the curvature. Add the two lengths.
If the marks at the ends of the bend are 15cm from the inside corner of the square, the total length of the curved section of the pipe will be 30cm
Step 5. Mark the matrix
Put the bent tube back into the bender and mark with a paint dot or notch on the die where the bend begins.
- If you have more than one tube matrix of different diameters, do a test bend in each configuration, because with different pieces the size needed to perform a 90 degree bend will change.
- Once you know the size needed to bend, you can calculate the length of the pipe by adding this factor (called the bend deduction) to the horizontal and vertical part of the pipe.
Method 3 of 3: Do multiple bends
Step 1. Measure the space the bent tube will occupy
For example, if you are making a roll bar for a dune buggy that will occupy a space of 150cm x 125cm, draw an equal rectangle with chalk on a flat concrete surface.
Step 2. Divide the rectangle by drawing a line in the middle of the long sides
Step 3. Measure from the corner to where the fold on the long side should start
If the top side of the roll bar is to be only 100cm long, subtract this measurement from the length of the base, then divide by two and you will get the measurement to mark from the corner. If the difference is 50cm, you will need to measure 25cm from each corner on the long side.
Step 4. Measure the distance between the low corners and the start of the fold
If the height from the bottom to the first fold of the roll bar is to be 100cm, measure this distance from the lower corners of the rectangle.
Step 5. Using a ruler, measure the line connecting the two marks at the ends of the fold to be made
In this case the diagonal is about 70cm long
Step 6. Lay your bent tube at right angles inside the rectangle
Place it so that the horizontal end of the tube touches the inside of the top side.
Step 7. Push the tube until it touches the diagonal drawn earlier
Step 8. Mark the point where the bend on the tube begins on the rectangle
Step 9. Rotate the piece so that the other mark on the tube touches the diagonal
Mark this point.
Step 10. Repeat the last four steps for the other top corner
Step 11. Calculate the total length of pipe needed
Add all the measurements from the bottom corners to the first marks, plus the top and bottom sides.
In the example, the vertical parts of the roll bar will both be 100cm, the diagonal parts will be 70cm, the horizontal part will be 100cm. The minimum total length will be 100 + 70 + 100 + 70 + 100 cm, or 440 cm
Step 12. Cut the tube to the required length
Even if the minimum length required is 440cm, it is good to leave a little margin, at least 10cm, reaching a total of 450cm.
Step 13. Find and mark the center of the pipe
You will work from the center outwards.
Step 14. Lay the tube on the top side of the rectangle, aligning the center of the tube with the center of the rectangle
Make a mark on the tube at the start of the bend on both sides.
You should also mark the direction of the bend by making arrows pointing towards the end of the tube
Step 15. Make both top bends with the bender
Make sure the welds are on the inside to prevent the pipe from warping.
- To make sure the tool is properly adjusted you can prepare a sample with two flat pieces of metal with the ends attached to a pin. Open them at the necessary angle and compare them to the angle of your bender.
- Check the correctness of the bends made by placing the tube against the drawn frame.
Step 16. Make the bottom folds
Follow the same procedure outlined in the previous steps.
Step 17. Cut the excess tubing
Advice
- Start with simple folds before tackling more complicated projects. You may need to carry out several tests to familiarize yourself with the tool.
- Use an adequate workspace. The metal tube can snap like a spring when bent, so you need to have the space you need to not get hurt. You will need at least 3 meters of free space around, even better double.
- You can spray the floor with special adhesive paints to prevent slipping as you work.
Warnings
- Check your tool and dies regularly after use. Even screws and bolts can bend or break from time to time.
- To bend pipes larger than 5cm in diameter, it is best to contact professionals.
