Its that time again, Oxfuel welding in the end of the summer. Why do we weld with this process, since most main stream production shops do not always utilize it?
Well, I like to introduce new welding students to this process because for one…. It is fun, secondly, it enables people who have never seen a weld puddle to learn how to control and manipulate it in a slow relaxed manner. If you need to weld something in a remote location with no electricity, it is hard to beat. Sometimes, the pops and cracks and mini explosions can cause fear and such but once anyone gets the basis down, it can be relaxing.
For starters, you need to understand how to set up the equipment.
- Determine the thickness of the metal you will be working with
- Choose the right tip for the thickness
- The regulators on most set ups have a working pressure gauge on the left and a tank pressure gauge on the right. You will need to consult the manufacturer for the working pressure settings for the tip you use. For example, a #2 tip (which is a good choice for 1/8″ metal) would require a working pressure setting of 3 Oxygen and 3 Acetylene. The same number is set for both .
- You would of course open the tanks to check for tank pressure first. The oxygen bottle needs to be opened all the way. Partly because you can and also because you need the valve to seat open with all the high pressure that it would be subject to over time. A full oxygen tank usually holds around 2,200 psi when full. The acetylene bottle holds around 300 psi when full. You will see in various books to open the acetylene only.. a turn and a half or a turn and a quarter or one full turn. The problem with this logic is you don’t know how old the valve is or how much wear and tear it has been through so my rule of thumb is to open the acetylene valve as many turns necessary to establish tank pressure. You check this by pressurizing the hose up to the torch body, then opening the valve on the torch to relieve the pressure and check to see if the working pressure and tank pressure gauges remain where you set them. It is that simple.
- Light the gas with a flint stricker and proceed to finding a neutral flame.
- This flame can be adjusted by opening the acetylene flame until the carbon soot goes away. Slowly add oxygen until all that is left is a blunt blue tip flame.
- When you are welding a lap joint or T Joint, you will need to add filler metal. The best rod for this is RG45 or RG60, which are both suited for gas welding as opposed to coat hanger wire.
- A forehand direction works best to get the hang of it. Practice, practice, practice….