Brazing copper pipe is a technique used to connect 2 pieces of pipe together, the technique is actually very similar to soldering. However, many people often ask the question, can you braze copper pipe that's wet?
Can You Braze Wet Copper Pipe
Technically, it is possible to braze wet copper pipe, however, the chances of problems are much greater. You should always try to avoid brazing or soldering anything that's wet, dirty or has grease on it.
Solder is a type of metal with a fairly low melting temperature. Trying to braze a wet copper pipe will be very difficult because the water will cause the solder to run rather than pooling in the joints. Where ever possible you should always try to dry the pipes before starting work.
Another important consideration is that water could potentially get behind the solder. If this happens then expanding or contracting caused by temperature differences could lift the solder off the joint.
Drying Wet Copper Pipe
Before brazing copper pipe it's a good idea to dry it using a cloth. If you're working on old pipes then you might find roughing up the surface a little using emery paper will also work very well. Emery paper should take off all the dirt and grime which has built up on the pipes over the years.