Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

Over the years I've soldered several remodels worth of copper pipe (water and hydronic heat). I'm not great, but I get the job done, until I have to add a brass fitting. For some reason, I can't get the solder to suck into the joint. Does soldering a brass fittings to copper pipe require a special technique?

share|improve this question

2 Answers 2

up vote 6 down vote accepted

Very Important Make sure the joint is really clean when you solder - so use emery cloth or sandpaper to remove any contaminants in your solder joint and flux the joint prior to heating. I like to wipe the joint with acetone before applying flux but I'm anal retentive like that.

Also you might want to consider using MAPP gas vs propane - those brass fittings take a lot of heat before you will get solder to flow into the joint.

share|improve this answer
3  
mapp gas is a must, never had much luck with propane. Lots of heat is the trick. –  shirlock homes Feb 5 '11 at 6:44
    
Cleaning and MAPP are key. I've never bothered with acetone, nor have I seen anyone do that before. Make sure your flux and brush are clean too: you just spent all that time cleaning the fitting, don't wipe a mixture of flux and dirt onto it. –  gregmac Feb 5 '11 at 6:57
    
Using solvent to clean the joint area after mechanical abrasion is a holdover from my electronics soldering days (definitely something I've never seen a regular plumber do). –  kkeilman Feb 5 '11 at 7:07

If the problem is that the solder is not "pulling" into the joint it may not be hot enough (try using MAPP instead of propane in your torch). But I find the biggest help is to use lots of flux (aka soldering paste). Go crazy with it, use it really liberally.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.