Purpose:

Brazing copper is a useful thing to know when working in a job site when you need to fuse two pieces of copper together.  The reason why is because not many people know how to braze good enough so there is not any leaks in the copper pipes.  Brazing is done with a torch that has a combination of oxygen and another type of gas.  Brazing is a process that combines two metals together by a filler metal.  The filler metal is heated above melting point and is applied between the two pieces of pipe.  The filler metal is brought slightly above its melting temperature while protected by a suitable atmosphere, usually a flux. When it reaches that melting point, then it flows over the cooper pipe and when the torch is pulled away the metal cools, which causes the two copper pipes to conjoin.

Safety:

Safety is very important thing to keep in mind when working with fire and a bright light.  When brazing, it is important to be in a area with some type of device that will put out a fire.  The reason why is because the heat from the torch or metal may cause a fire.  Also dangerous are the tanks that supply the gas and pure oxygen to the torch.  These tanks sometimes have bad fittings and may have a leak that is undetected.  When the tanks leak, they may cause a fire because of the type of gas or liquid they come in contact with.

Materials for Safety

·        Leather gloves

·        Long sleeved leather jacket

·         Glasses (sunglasses will work)

Material's needed to Braze

·        Flux (a material that is made of liquid, paste, or a powder, that cleans the pipe) 

·        Copper pipe/fitting

·        Filler metal

·         Oxygen tank

·        Fuel gas (Acetilene, or naturel gas) 

·        Torch

·        Striker

Work Space

The work space needs to be clean and have the least number of hazards as possible.  the work space needs to be clear of people with no eye protection, for their own safety. 

Purpose of Flux 

The purpose of flux is to prevent oxides from forming while the metal is heated. The flux is also helpful to clean the pipe for a better fit and for less leakage.  There are many types of flux to put on the filler metal, such as flux paste, liquid, powder or pre-made brazing pastes that combine flux with filler metal powder.  Some flux is already applied on the rod, like a wielding rod.  After the flux is applied on the rod, the flux will be displaced by the molten filler metal that enters between the two pieces of copper.  Leftover flux should be removed when the cycle is completed, because flux left in the joint can lead to corrosion.

Filler Material

The filler material can be pre-placed in the copper pipe or applied during the heating cycle. For circumstance, we will be doing manual brazing.  This will consist of a wire or a rod, which is generally used because they are the easiest to apply while heating. The rod will be dipped in the flux because we are not using a copper rod.  If you are using a copper rod and brazing it to copper tubing, then you do not need flux. 

How to Set up the Tanks

When you set up the tank's there will be many different ways to set the gauges to.  For are situation we will be setting the tanks at 20 oxygen and 10 for the fuel gas.  To get an accurate reading, open the two vales on the torch so you are able to adjust the gage.  After you let the torch bleed out, put the oxygen to 20 and the fuel gas to 10.  

Getting Started

Since you have all these steps done you can know start brazing. 

·        Get your station ready with all the materials 

·        Make sure to inspect the bottles before and after you turn them on for any leaks (smell, hear, and see)   

·        Get your safety equipment on and turn on the gas to the right settings

·        Get your torch and crack open the gas on the torch

·        Get your striker and light the torch

·        Open the gas valve on your torch till the black smoke goes away

·        Apply a little oxygen till you get a flame that is not fluffy and has a nice small inner white flame (1/2in to 1in), that flame is the hottest part

·        Get your rod and heat it up a little, then dip it in the flux

·        Apply heat in a slow back and forth motion to your copper pipes where the two fittings meet, because that is the thickest part

·        Wait till the pipe is red hot, but do not burn a hole through it.  Then apply your rod to the part that needs to be sealed, starting with the bottom first.  Then, work your way up

·        After the rod is applied, use your torch flame and smooth it out, and make sure it is bubble free/lump free

·        Wait to for the braze to cool

·        Take off any leftover flux with a rag

KNOW YOU SHOULD HAVE A GOOD BRAZE!