Soldered Pipe Joints – A Quick Guide

When it comes to joining pipes there are several options for the DIYer ranging from screw together plastic, compression and soldered joints. These options have their good and bad points and are all employed by professionals depending on particular circumstances and requirements of any one job. An option often avoided by the amateur, however, is to use soldered joints. Carried out with care and attention a soldered joint will perform well while offering strength and a neater looking – professional finish.

If you recall those metalwork lessons at school, the process of soldering and brazing joints consisted of a neat fitting joint free from dirt and grease etc. The best way to clean brass pipes is to scrub the areas to be jointed with a little wire wool. Don’t forget to also clean the joint, as all surfaces need to be clean. Remember the word flux from your school metalwork days? Flux will help clean the joint by removing oxides from the surfaces of the pipe. Flux should be painted on the appropriate parts of the pipe and fixing. On the subject of flux, it’s worth noting there are many types. Much depends upon the type of metal we are jointing and the heat involved. Make certain you have flux, which is appropriate for soldering brass pipe. Some joints come ready impregnated with solder, but it’s still good to check cleanliness, flux the joint and have extra solder to hand.

Before reaching the point of cleaning and fluxing it’s always worth assembling as much pipe-work together as possible. In carrying out a dry fit, it’ll be more evident where sections can be modified to simplify or neaten the job.

Solder melts at fairly low temperatures (approx 180 degrees C) in comparison to brass (c 750) or silver (c 650) rods. Therefore the pipe and joint should reach the correct temperature quickly. If work is being carried out in confined areas ensure flammables are well out of the way and protective matting is used to keep heat away from things you’d rather not damage. As the soldering wire is offered up to the joint it should melt from the heat of the pipe rather than direct heat from the blowtorch. Through capillary action the solder should flow in and around the joint. With solder impregnated joints, solder should emerge to the outer edges. The best joints are done quickly and without fuss. A minute or so heating should be enough. Heavier duty joints may take a little longer but if you are applying heat for several minutes or the pipe has been glowing a dull orange for a while, the job should be done. If at this point the solder congeals into droplets then there’s a good chance the joint wasn’t properly clean or has become dirty from prolonged heating. In these cases it’s best to start again…possibly replacing the joint unless it’ll properly clean up.

Once you’ve mastered the art of soldering you’ll appreciate how much more solid the joint is and how much more versatile you can get with your arrangement of pipes, especially in restrictive areas such as under sinks and baths etc.