How much flux should be used when soldering a pipe?

Answer 1

Enough so that when you use a flux brush and paint it on the fittings there is a uniform coating all over before you apply the heat. And that is not much - maybe a couple of blobs about the size of a green pea.

Answer 2

Clean the end of the pipe with 'wet and dry' paper or emery cloth. Clean it by going around the pipe, not longitudinally. (that's important). Wipe the cleaned area with a smearing of flux. Apply heat just before the cleaned area, NOT on it otherwise you will quickly cause oxidation. Your torch should be about 60% of it's max. Too hot and the copper will oxidise, too cool and it won't be hot enough to melt the solder. Ensure that you are using the correct melting point solder for the job. Hold the solder in one hand and apply it to the tube, playing the flame on and off and round the pipe. You need to get the heat to just the point where the solder begins to run. As soon as the solder runs, wipe it round with a mole skin cloth. (I use a leather garden glove, it works a treat, I can wipe it round and clean without getting burned leaving the end just silvered. When you have mastered that then you can move on to joining the pipes together with an end solder socket or, if you prefer, a yorkshire soldered socket. If the copper pipe changes color to a light reddish brown then you have applied too much heat. Likewise if the solder runs off like water. You need to get the heat to where the solder is between running off and being plastic.

Answer 3

How much? Use a brush and apply a thin coat. Flux is used to help make the solder flow easier. The biggest thing is to make sure your joints are clean and shiny, free of any oils and dirt. Don't touch a clean joint even with your fingers. Make sure your heat source is "above" the joint you are soldering, as it is the heat that draws the solder into the joint itself.

Answer 4

Tough to describe.
Coat the 2 pipes with flux and don't worry about if you put too much on. The excess will get thin with heat and drip away.
It can make a mess of what's under it so be ready.
Solder is another story.

Answer 5

Surprisingly, it takes very little.
When you apply it, a thin coat inside the fitting and on the fitting area of the pipe is all that is needed.

Johnson's if a very good brand by the way. So is Laco

NoKorode separates in the can and has caused problems for me on the job, so I stay away from it.

Flux prevents oxidation which hampers solder from attaching to the copper.

Answer 6

A thin layer of flux inside the fitting and on the pipe is all that is needed. Any excess will merely melt and run off.

Answer 7

The flux should flow up the pipe. It is more an art than a science.

Answer 8

Just use enough flux to coat the inside and outside of the surfaces.