How much solder?? - DIY Chatroom

geobckmstr · 10-30-2009, 11:16 AM

an old plumber once told me whem soldering pipe to use for 1 inch pipe bend 1 inch of solder and use that much,3/4 inch bend 3/4 inches etc. now i just read that for 1/2 inch pipe use 2 to 3 inches??? thatseems like alot?? what to do???

Piedmont · 10-30-2009, 06:09 PM

Well, the math doesn't work out like that.

A 1/2" fitting has a 0.25 radius and 1/2" deep = surface area for solder of 1.17
A 3/4" fitting has a 0.375 radius and 3/4" deep = surface area for solder of 2.65
A 1.0" fitting has a 0.5" radius and 1" deep = surface area for solder of 4.71

It's not linear. If you use 1/2" for 1/2" fitting and are happy with it you need to use 1 1/8" of solder for 3/4" pipe and 2" of solder for 1" pipe to keep the ratios. Experienced plumbers know also, this means 3/4" pipe is over 2x harder to seperate dryfit connections than 1/2" and 1" connections are 4x harder (I don't recommend dryfitting 1" connections you will not have much luck being able to pull them apart no matter how much you try).

AllanJ · 10-30-2009, 06:15 PM

It's hard to say because the diameter of the solder strand varies from one brand to the next.

If a drop of solder should fall from the "bottom" of the joint then the joint should have been fillled and sealed with solder. Except that this might not happen when the pipe is inserted into the fitting from above. Then the best you can do is feed in a little more solder after you see silver all the way around the joint.