Sweat soldering is the most popular method for connecting copper pipes. Done properly sweat-soldering is both effective and inexpensive. If not done right and correct however, sweat soldering is not effective as a plumbing and heating furnace equipment procedure and it can be disastrously expensive.

Unlike conventional soldering with an iron or soldering gun you sweat torch with a torch. Most people use a propane blow-torch, which is both easier and safer to operate than a blow torch. In addition to the heat source, you need a good nonacid paste flux, emery cloth and a 50/50 solid-core solder.

At least as important as having the right materials is properly preparing the pipe to be sweat soldered. There are three key factors necessary and essential to assure good sweat-soldered joints: clean copper, totally dry pipes and proper heat. If you are dealing with newly cut pipe or tubing, ensure to remove all burrs from both the inside and outside of the cut end of the piping. Of course, if the cut end of the pipe has been bent or crushed in the cutting process, take care to start over with a freshly cut length of pipe. The end should be and has to be perfectly round. Then, check the fittings to be sure that the joint will be tight.

One word and note of caution. One of the most crucial factors in sweat-soldering is making sure that the pipes and fittings are completly and fully dry. If there is any residual moisture. This moisture will turn to steam when the pipes are heated, and the end result will be a weak or even leaking joint. The build up of trapped steam in a copper plumbing, furnace or hot water heater pipe could actually cause an explosion. Therefore, before you actually start putting the pieces together, make 100percent perfectly sure that no moisture is lurking anywhere. If you are soldering on parts of the plumbing system or systems drain the pipes and leave the faucets open so that steam buildup can escape and run off.

There are also a couple of techniques that will help you to dry the copper plumbing & furnace pipes more than thoroughly. If you are sweat soldering to a vertical pipe, you can use a rag to remove any moisture, but if the connection is to be made to the horizontal run of pipe – then try this tried and true heating and plumbing professional tradesperson’s trick. Wad a piece of white bread into a ball, poke the bread ball into the pipe, and push it back into the area that you will be soldering . The bread will absorb moisture that otherwise reach the joint you are working on and ruin your sweat-soldering plumbing project. When the job is completed, you simply turn the water back on, the bread will dissolve and the residue will come out of the nearest tap or hot or cold running water faucet.

Now, clean all the metal surfaces that you plan to join. Fine steel wool or sandpaper can be used for the job. However the best way to clean the outside of a pipe is to wrap an emery cloth around the tubing or pipe and go “back and forth” as if you were buffing a shoe. You want the metal to shine, but be careful not to overdo it. The last thing you want to do is to take away so much metal that you lose the snug fit. On the other hand though do not forget to clean every surface that will be part of the sweat-soldered joint, including the fitting where the pipe will go.

Once you have applied the flux and joined the pipe to the fitting, you are finally ready to solder. It seems that the majority of the work to sweat solder is the preparatory cleaning and inspection steps of the procedure. Light your propane torch and get the solid-core solder ready in your other hand. In most cases you will have to heat the copper to about 400 degrees Fahrenheit. Play the flame over the fitting – not the pipe. Do not put the flame on the solder: the solder should melt when it comes into contact with the hot fitting and pipe. Be careful not to overheat the fitting and pipe. You can test these by touching the joint with the solder to see if it melts.

A major point and emphasis concerning safety precautions when sweat soldering. The entire process is actually quite simple however you must ensure that you take some relatively standard safety as well as fire prevention precautions. If you are working close to a wall or ceiling place a length of fire and heat resistant material, gypsum wallboard or a piece of heavy aluminum foil between the pipe or the wall or ceiling. Otherwise if you were accidentally to point the torch in the wrong direction you could char the surroundings or even start a fire. Be especially careful to keep the hot flame away from already soldered joints or valves nearby. Wrapping wet rags around good soldered joints and valves is one way of dissipating heat as well as preventing the flame doing any damage. One other safety rule. When you finish sweat soldering the joint, turn off and extinguish the propane torch immediately.

Lastly many amateur plumbers and home handymen (or handy women) are so very proud of their sweat-soldered joints that they immediately turn on the water. That however is a big mistake. Be extra sure to allow the joint to cool naturally: the sudden cooling effect of the rushing water can weaken the joint or even cause it to crack and fail when you do turn on the water pressure fully. Take your time to let the pipe cool fully. It’s worth the extra time spent. A couple of minutes spent waiting can save you hours and hours of a wasted plumbing or heating repair or renovation upgrade job to your plumbing or furnace system which will have of course to be redone.

Author Bio: Harold Stofman Furnasman’s One Hour