Sweating Copper to Brass

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by robojet, Sep 27, 2005.

  1. robojet

    robojet New Member

    Messages:
    14
    Location:
    So. Cal.
    Hi all...

    I'm remodeling my kitchen/family room and have found myself learning some new things. I've capped off some copper pipes, which I found pretty easy to do :D , but I've run into a bit more difficult plumbing issue:

    I need to move the water supply for the refrigerator about 6 inches to make room for a larger pantry. Currently, the valve sticks out from the wall. I bought one of those recessed boxes with valve, so the valve won't stick out anymore. The instructions say to solder the copper to the brass valve. Since this will be in the wall (rather than the current valve which is compression and accessible outside the wall), I feel that soldering would be best (plus the fact I don't appear to have any other options).

    So, here's the question(s): I bought the plumbing kit with flux, solder, etc. in it (already had a propane torch). Can I use the same flux, solder, torch for joining brass and copper? How long does it take to heat the brass? The brass appears to be about 1 1/2" deep - do I put 1 1/2" copper inside it? If so, how much solder will that require? Please add any additional information that I may have neglected to ask about.

    I have read other posts, so I know I'm suppose to open the valve.

    THANKS!
  2. chassis

    chassis Engineer

    Messages:
    339
    Location:
    SE Pennsylvania
    For the refrigerator, you're not talking a very large supply pipe, right? In that case, it won't take long (1 minute or so) to heat the parts to the proper temperature. Make sure to put a heat shield (HD/Lowe's has them) between the flame and the wall so you don't burn up what's behind the valve. Dry fit the parts together before you fire up the torch to make sure you know what is connect to what and that the parts go together.

    The valve probably threads onto a brass fitting, right? Then the brass fitting is soldered to the copper pipe? If so, I would solder the brass fitting to the copper pipe first, then use telfon tape on the valve threads and screw it into the fitting. That way you won't burn up or melt the seals inside the valve, if there are any.
  3. robojet

    robojet New Member

    Messages:
    14
    Location:
    So. Cal.
    Thanks for the info... I will need to get a heat shield - and great suggestion on removing the valve from the equation for the purposes of soldering!

    The supply line is 1/2" copper and would slide into the brass pipe. The brass is fairly wide, as it is threaded on the outside (apparently for multiple applications).
    Last edited: Sep 27, 2005
  4. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,397
    Location:
    Yakima WA
    Heat shields are great, but for just an occasional solder job where you need one, you can take a #10 can, take the bottom off then open it up. Put this between the joint and the wall and you can protect the wall just fine. If you were a professional, the real shield would be money well spent. Remember when you solder, it is the heated joint that melts the solder, not the flame of the torch. The brass will require more heat than copper, but it's the same procedure as with copper to copper. You might want to have water handy just in case you get something too hot in spite of the heat shield.
  5. robojet

    robojet New Member

    Messages:
    14
    Location:
    So. Cal.
    I like the can idea... that helps.

    Also, I've been considering the approach on doing this, and it might be best to join the copper and brass in the garage rather than in place... I can always leave a copper to copper join for the last step when working in the wall.

    I still need to know about if I should insert the copper pipe all the way into the brass (about 1 1/2") and if that effects the area I apply flux and the amount of solder. Also, can I use the same solder/flux for the copper-brass as I did with the copper-copper.

    THANKS!
  6. Kristi

    Kristi Tradesman Plumber

    Messages:
    176
    Location:
    Vancouver, BC
    Same flux, same solder (I use lead free). Insert the copper all the way, flux everthing that is involving solder. Heat the brass fitting, it will take longer than the copper. My heat shield? The stainless shroud from an MJ clamp, lol... 1.5" sounds like a deep socket, are you sure you have the correct fitting? Just checking, most are only about 5/8" or so... ;)
  7. robojet

    robojet New Member

    Messages:
    14
    Location:
    So. Cal.
    Thanks Kristi! I think I'm ready to give it a try now... :D

    I wasn't home when I posted the original message... I've rechecked the depth of the pipe... it's 1/2" - my memory wasn't serving me well :eek:

    I really appreciate everyone's help. Hopefully I can give this a try tonight and I'll post the results!

    Jennifer.
  8. chassis

    chassis Engineer

    Messages:
    339
    Location:
    SE Pennsylvania
    robojet, sounds like you've got the picture. I was thinking 1/2" sounded more right than 1 1/2". And also good that you're planning to do the soldering with the valve removed.
  9. robojet

    robojet New Member

    Messages:
    14
    Location:
    So. Cal.
    Well... I think I've done it :) -but it took me a couple of tries (which is why I'm saying I think)...

    It took much less time to heat the brass than I thought (about 10-15 seconds). When I soldered it the first time, it didn't appear that one side had taken the solder very well - so I took it apart, cleaned it up a bit and did it again. The second time went much better.

    Here's the questionable parts:
    1 - The first time I heated it much longer than needed. Is there any problem with heating the brass or copper too long?
    2 - When I took it apart, there was still solder inside the brass pipe and on the copper. I had heard about pre-tinning, so I was thinking that this was no big deal... so I went forth and resoldered as is.

    I haven't hooked this up to the supply line yet (I didn't have a copper elbow I needed to finish the job... but I'm wondering if I've already caused a problem.

    Your help is very much appreciated!
  10. chassis

    chassis Engineer

    Messages:
    339
    Location:
    SE Pennsylvania
    Best way to test it is to turn the water on and look for leaks.

    Can't heat copper or brass for too long with a propane torch. Mapp gas or oxy/acetylene is another story. ;)

    One suggestion for getting proper heat on all areas is to heat one side of the joint, and touch the solder wire to the other side, 180 degrees from your torch. If the solder flows, then the "cold" side of the joint is hot enough, and the hot side is guaranteed to be hotter. This assures that you're getting solder in 360 degrees of the joint.
  11. robojet

    robojet New Member

    Messages:
    14
    Location:
    So. Cal.
    Well... I suppose this is kinda funny...

    I was working on the copper elbow... I had already reassembled the valve in the plastic box. Since the copper fitting was about 6 inches away from the box, and I only heat the copper for a few seconds, I thought all would be well --- ha! not only did the end I was working on heat up, the whole brass valve heated up and melted the box! :eek: My mistake, and a lesson learned - that will never happen again ;)

    Anyways, I didn't want to go through anymore of this, so I dumped the recessed box idea and just went for the copper line coming out of the wall with a compression valve attached (as I had before).

    I do appreciate the help I got here, and I now know how to join brass and copper - it will probably come up again some day!

    THANKS!!!
  12. TheLink

    TheLink New Member

    Messages:
    7
    Fire extinguisher

    All plumbers should have a fire extinguisher AND a bucket of water handy when working in a wall. But especially home handy men or when the water to the building is turned off. I have known of more than one house burned to the ground.
  13. Kristi

    Kristi Tradesman Plumber

    Messages:
    176
    Location:
    Vancouver, BC
    This summer an entire apartment building burned to the ground - people were rescued, pets perished... all from one poor thoughtless plumber who was soldering earlier in the day. He had the tiniest ember get going in the wall, I'm sure he had no idea about it until the 6 hours later when it was all over the news. Pretty scary stuff that keeps this plumber on her toes!!!
  14. robojet

    robojet New Member

    Messages:
    14
    Location:
    So. Cal.
    You'll be glad to know that I had a fire extinguisher at my side... :D
  15. slb

    slb New Member

    Messages:
    48
    Location:
    San Francisco North Bay
    Another DIY'er here. FYI, I installed one of those recessed boxes behind our fridge about three years ago and had the same thing happen; the plastic box melted where the valve was attached to it. Fortunately, it wasn't so bad that I had to scrap it.

    -Steve
  16. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,272
    Location:
    Cave Creek, Arizona
    [ Since the copper fitting was about 6 inches away from the box, and I only heat the copper for a few seconds, I thought all would be well --- ha! not only did the end I was working on heat up, the whole brass valve heated up and melted the box!

    I can tell you two things for sure. One, you did not heat the fitting for just a few seconds, and two, you had the elbow much too hot. You should have been able to solder the copper into the valve, while it was in the box, and not have melted the box if you used the proper amount of heat.
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