# Seeking Advice on DIY project: Soldering copper pipes for pumbing **URL:** \ **Category:** In My Humble Opinion\ **Created:** [July 14, 2018, 4:32pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902 "2018-07-14T16:32:40Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 14, 2018, 4:32pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/1 "2018-07-14T16:32:40Z")
PLUMBING! Tomorrow I have a little DIY project. The supply valve for hot water to my washing machine sprung a leak and I need to replace it. I’m going by [this wikihow article](https://www.wikihow.com/Sweat-Copper-Pipe), but wanted to see if anyone here would care to chime in with some advice. For the record, I’ve kinda-sorta done this once before. It was about 10 years ago and I had to replace my hot water heater. As part of the process, I had to re-plumb the overflow lines. Things seemed to go fine, but those lines were not under pressure and actually have never be used. Unfortunately, the line is plumbed in a way that makes a little extra work. The copper line goes down from the valve, makes a quick 90 deg turn, runs for about 5 or 6 inches, and the 90 degrees again upward. I figure it’ll be easiest to cut it on the upswing after the turn and then replace what will look like a U shaped section. Two elbows and a straight connector. The wikihow article says to reheat the joint after you’ve soldered it and has cooled down. I wasn’t aware that this step was necessary (I guess they say to do it if you’re a beginner, and that’s me). Any thoughts about that or anything else I should be aware of? Thanks!! ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [July 14, 2018, 4:37pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/2 "2018-07-14T16:37:51Z")
Unless I misread it, the ‘reheat’ step is to apply the solder. Before that it says to coat everything with flux and then, before joining them, heat them until the flux burns off. Ignore that article. Just go find one of the millions of youtube videos. Watch it and don’t overthink. ETA, if you’re concerned, pick up a few feet of copper and some connections and practice soldering them. If you can make it so there’s only one opening, you can attach a fitting to it so you can screw it into a garden hose and leak test it to see how you did. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 14, 2018, 4:43pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/3 "2018-07-14T16:43:18Z")
> [@Joey\_P](#): > > ETA, if you’re concerned, pick up a few feet of copper and some connections and practice soldering them. Yep, already plan to do this. Good advice, though. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 14, 2018, 4:47pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/4 "2018-07-14T16:47:12Z")
The key is to sand all the connections - inside and out - completely clean and shiny. Even sand brand new fittings. If you do this, and use a proper water-soluble flux, the soldering will be a piece of cake. Simply heat the joint, and apply the solder to the other side of the joint, once it starts to flow, just wipe the piece of solder around the hot joint, and turn off the torch. It will be obvious if it’s good joint - the solder will wick into the joint. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 14, 2018, 4:54pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/5 "2018-07-14T16:54:58Z")
> [@beowulff](#): > > The key is to sand all the connections - inside and out - completely clean and shiny. Even sand brand new fittings. > If you do this, and use a proper water-soluble flux, the soldering will be a piece of cake. Simply heat the joint, and apply the solder to the other side of the joint, once it starts to flow, just wipe the piece of solder around the hot joint, and turn off the torch. It will be obvious if it’s good joint - the solder will wick into the joint. Thanks. Yeah, I remember when I did it before that it was pretty obvious when the heated pipe was ready to accept the solder. It’s almost magical the way it works! 🙂 I’m only a little nervous because the lines I soldered before didn’t have to work under pressure. I’m pretty sure I did everything right, and it didn’t seem too hard, but I figured I check in here for advice just in case. ---
**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\ **Post date:** [July 14, 2018, 5:14pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/6 "2018-07-14T17:14:18Z")
I have to say this: Be careful with whatever is _behind_ where you’re soldering; one can get so involved with creating a good solder joint that you don’t realize you’ve scorched the framing or set fire to the drywall. Safety first! ---
**Author:** ![Scumpup](https://avatars.discourse-cdn.com/v4/letter/s/ce73a5/32.png) [@Scumpup](https://boards.straightdope.com/u/Scumpup)\ **Post date:** [July 14, 2018, 5:45pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/7 "2018-07-14T17:45:42Z")
Unless you are determined to solder for the sake of soldering, I recommend you use Shark Bite fittings. They are quick, work well, and avoid the dangers associated with using a torch near flammables. ---
**Author:** ![MikeG](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikeg/32/4329_2.png) [@MikeG](https://boards.straightdope.com/u/MikeG)\ **Post date:** [July 14, 2018, 5:54pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/8 "2018-07-14T17:54:55Z")
Unless you are determined to deal with leaks and possible joint failure, I recommend you solder the joint. Press on fittings such as Sharkbite and Tectite are popular but I have witnessed may flooded home stories. I sell plumbing products ya and no plumber I know would use them in their house. It sounds like you could just cut the U off, solder on a male adapter and then use an angle stop that threads onto the adapter. That would give you the most secure joint. There are also straight stops if the results in less bending of the supply line. There are also pads to absorb the flame while soldering. insurance pad is another name for them. Highly recommended. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [July 14, 2018, 6:01pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/9 "2018-07-14T18:01:16Z")
If you’re new to sweating pipe, buy a bunch of extra fittings and pipe, and do _lots_ of practicing beforehand. When feeding the solder to the joint, don’t feed it too much solder. If you do, a blob of solder will form inside the pipe, and could eventually break off and clog a valve downstream from it. ---
**Author:** ![Scumpup](https://avatars.discourse-cdn.com/v4/letter/s/ce73a5/32.png) [@Scumpup](https://boards.straightdope.com/u/Scumpup)\ **Post date:** [July 14, 2018, 6:02pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/10 "2018-07-14T18:02:27Z")
You have witnessed many flooded homes or you have heard many flooded home stories? You weren’t clear and those two things aren’t the same. I have used Shark Bite products several times to make repairs in areas where I didn’t care to use a torch. The oldest has been in place for a decade without leaking a drop. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 14, 2018, 7:05pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/11 "2018-07-14T19:05:28Z")
> [@MikeG](#): > > It sounds like you could just cut the U off, solder on a male adapter and then use an angle stop that threads onto the adapter. That would give you the most secure joint. There are also straight stops if the results in less bending of the supply line. Hmm. Never thought of that. I might go that route! And now that you mention it, I did quite a bit of that type of plumbing in physics labs back in college. > [@](#): > > There are also pads to absorb the flame while soldering. insurance pad is another name for them. Highly recommended. Good idea. ---
**Author:** ![Mean\_Mr.Mustard](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mean_mr.mustard/32/3865_2.png) [@Mean\_Mr.Mustard](https://boards.straightdope.com/u/Mean_Mr.Mustard)\ **Post date:** [July 15, 2018, 11:36am UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/12 "2018-07-15T11:36:22Z")
If you own a fire extinguisher, keep it close at hand when soldering. If not, keep a full bucket of water nearby. This may seem like overkill, but it certainly wouldn’t hurt. mmm ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [July 15, 2018, 1:35pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/13 "2018-07-15T13:35:57Z")
I’m only a mild DIYer and have sweated pipes several times, no leaks yet. One thing to be careful of when sweating existing pipes is to make sure there’s no water in the pipe. The heat can make any remotely nearby water steam and even boil which is not good. Have a thick rag and good gloves handy to wipe away any excess solder while it’s still liquid. Pros know how much solder to use to avoid this. DIYers typically don’t. ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [July 15, 2018, 2:09pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/14 "2018-07-15T14:09:00Z")
> [@Mean\_Mr.Mustard](#): > > If you own a fire extinguisher, keep it close at hand when soldering. If not, keep a full bucket of water nearby. > > This may seem like overkill, but it certainly wouldn’t hurt. > mmm Not overkill at all, and a simple safety. And wet down any wood/drywall that will be near first. A spray bottle can come in handy to do this, and a bucket of water and rags. ---
**Author:** ![MikeG](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikeg/32/4329_2.png) [@MikeG](https://boards.straightdope.com/u/MikeG)\ **Post date:** [July 15, 2018, 2:50pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/15 "2018-07-15T14:50:46Z")
> [@Scumpup](#): > > You have witnessed many flooded homes or you have heard many flooded home stories? You weren’t clear and those two things aren’t the same. > I have used Shark Bite products several times to make repairs in areas where I didn’t care to use a torch. The oldest has been in place for a decade without leaking a drop. I work for a plumbing supply company. I have had many conversations with both plumbers and homeowners following sharkbite failure floods. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [July 15, 2018, 4:18pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/16 "2018-07-15T16:18:35Z")
Get yourself a fireproof pad to sit behind the pipe. ---
**Author:** ![Dobbs](https://avatars.discourse-cdn.com/v4/letter/d/5f9b8f/32.png) [@Dobbs](https://boards.straightdope.com/u/Dobbs)\ **Post date:** [July 15, 2018, 5:33pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/17 "2018-07-15T17:33:23Z")
NM - didn’t read the whole thread ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [July 15, 2018, 6:28pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/18 "2018-07-15T18:28:59Z")
This Old House has lots of good videos on soldering. [Soldering for the first time](https://www.youtube.com/watch?v=nVom-6VROxo) [How to solder pipes](https://www.youtube.com/watch?v=gMw8S7r0sZM) It really is pretty simple. 1. Make sure the pipe and fittings are completely shiny (inside and out) 2. Put the stuff together 3. Apply flux 4. Apply heat 5. Wait for flux to boil 6. Apply solder opposite to the heat source I’ve done it a few times with good results on the first try, and I’m a damn idiot. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 15, 2018, 7:07pm UTC](https://boards.straightdope.com/t/seeking-advice-on-diy-project-soldering-copper-pipes-for-pumbing/817902/19 "2018-07-15T19:07:34Z")
> [@friedo](#): > > This Old House has lots of good videos on soldering. > > [Soldering for the first time](https://www.youtube.com/watch?v=nVom-6VROxo) > [How to solder pipes](https://www.youtube.com/watch?v=gMw8S7r0sZM) > > It really is pretty simple. > > 1. Make sure the pipe and fittings are completely shiny (inside and out) > 2. Put the stuff together > 3. Apply flux > 4. Apply heat > 5. Wait for flux to boil > 6. Apply solder opposite to the heat source > > I’ve done it a few times with good results on the first try, and I’m a damn idiot. I always flux the pieces first. It makes assembling them much easier, and the solder wets the joint better.