How To Bend Metal
Watch this video to learn how to bend metal. It clearly explains what devices are needed to get the metal bent properly and give a demonstration on how to do so.
One of the reasons that copper tube is so popular and chosen so often for making pipe work out of is the fact that actually, it's a very malleable metal. It means that you can form bends in it. You can change its shape.
We choose table X or half hard copper. If it was hard tempered, it would be too rigid to break. If it was soft copper, it wouldn't be strong enough to cope with being invertible sections.
It would push out of shape. So, we go for a temper which is half hard. This allows us to bend the copper tube into the shapes that we need it.
Why would we choose to bend rather than use a fitting? To start with, there's the cost element. Every bend that we pull will save us the cost of a fitting. It also means if we make no joins, then there's no chance of us making another leak.
So, the fewer fittings that we can use, the fewer leaks that we're likely to have. It also is a restriction to the flow. By choosing a long slow bend very much like we have on motor ways, we have long slow bends rather than short ones.
It means that we can travel faster. The physics are the same for water. If we pull a long slow bend, it means that the water can travel faster in that change of direction than if we used a tight 90-degree fitting.
So, the process for bending copper, we will tend to use a scissor bender or a bending machine or copper pipe benders - a lot of different ways of explaining them. Essentially, what we have is a former in which the bend is going to be formed. We have the keep which is the piece that's going to hold the copper in place, to keep it in place, and then we have a roller arm and a back knife or guide that locks in.
So, that's a fairly elaborate way of dealing with a piece of copper tube. Why we're doing that - if we took a piece of metal and simply tried to bend it with our hands, it would collapse. The point of most stress would fold in.
The outer piece would fold out. The sides would come out and the joint would simply, the pipe would simply collapse in on itself. So, to stop that from happening, we trap it.
We trap in a shape where it's held in its round shape. So, as the copper stretches during the bending process and tries to expand out sideways, it can't because it's held in the circular shape. There is a line in which the bend takes place.
It pivots on that point, passes up through the back knife, through the former, and through the roller arm. As long as the equipment is in good condition and hasn't worn then, the bend will take place at the point of contact. Occasionally, bends will ripple.
This tends to tell you that your equipment is starting to wear out and that there is now a bit of play. So, as some of that expansion and some of that stretches back into their own place, so to form the bend, we simply bring the two arms down together. It forces the copper tube around the former.
As we said, it's held by all these other components. So, it has to follow that line and it is in a position that it can't collapse and it can't crease. We simply bring it around.
There are several different ways of checking when we achieve a 90-degree. One of the popular ways is to use a set square. And again, there are different ways that we can use the set square.
We can bring it down onto the back of the back knife, or we can use our eye, then to line up those two, so the pipe is now in line with the set square, or we can take the pipe out, physically put it onto the desk and set within the square. What you'll find is that as you practice, you'll need to do less and less checking and you'll start to be able to see when a bend is achieved when you've got to your 90. You remove it from the former, check the angle, and that's how we bend metal. .