Detailed How-To with detailed pics – Owen Stevens
I written in the past about how I set up my water cooling system and I realized that some of my ‘learnings’ could probably be of use to others. I’ll cover how I assemble my threaded fittings and a primer on soldering copper pipe, as well as some info on valve types.
So first I’ll show you a combination of brass and nylon fittings. I put these together by simply threading them together, but really there is more to it than that.
To avoid leaks and to make assembly easier, you first need to wrap the threads of each part with Teflon tape (less than $1 at any plumbing or hardware store).
When you wrap pipe threads, you always want to go in the same direction as you would go while tightening the fitting. A good tool it to use is “righty tighty – lefty loosey”, referring to the direction of turning as viewed from the ‘end’ of the threads. Turing clockwise is for tightening and counter-clockwise for loosening.
If you have had physics or engineering, you can use the “right hand rule”. This means that if you make a “thumbs up” with your right hand – if you turn the nut/fitting in the direction the curled fingers on your right hand, it will move in the direction your thumb points. Also, it’s important to remember that as you combine fittings, you should always ‘hold’ each fitting with a wrench or vise. If you don’t and you have a long combination like above and only hold the end, you will have to tighten ‘through’ each fitting until finally the last one tightens.
This might be fine, but it also might over-tighten the other fittings, which can crack the parts. Not everyone is aware of the fact that pipe threads have a taper to help them seat. This means that as the threads tighten, they also start to press harder on the wall of the receiving fitting.
I’ve seen brass and steel spilt from over-tightening and of course, plastic will for sure. So take it easy when tightening, use Teflon tape and your results will be great.
Copper Pipe is actually some of the easiest stuff to make plumbing systems with if you learn the jargon and a few tricks.
A general word about pipe – OK – a few words! It’s important to remember that pipe is specified by a nominal size and wall thickness, or schedule. A larger schedule means thicker walls; for example, a ½” schedule 80 pipe is thicker walled than ½” schedule 40 pipe.
Copper pipe is a little different because it is more like seamless tubing and is usually specified as Type M, L or K. I used type L that has the dimensions of 0.625-inch outer diameter and 0.545 inch inner diameter. Not really ½ inch at all now, is it? Just a taste of the strange naming conventions engineers encounter.
Pipe Fittings: The specialized bits of pipe you use to connect things or do turns are called fittings. You can get ‘elbows’ – 45 degree bends, 90 degree bends, unions to connect two pieces of pipe of similar or dissimilar sizes, three way connections called tees or T’s, even threaded ends. It is important to note that a fitting has a larger inner diameter than the pipe it receives. Most copper fittings are like this – larger in inner diameter than the pipe’s outer diameter.
Here is a copper ‘T’, very useful.
I’ve used these threaded ends lately as well as the female version. Note these are pipe-type threads – remember the taper.
Cutting: To cut copper pipe, the best option is to use a tubing cutter, as shown here. I have used a hacksaw, but it is a lot tougher to get a nice flat, even end.
I’ll first show how you set this cutter up. You simply measure the pipe length and make a mark. Set the cutter on the mark like this – notice it has a roller and a sharp wheel – this is how it cuts.
You ‘roll’ the cutter around the pipe while gradually tightening the knob on the end of the cutter to tighten its grasp on the pipe; this pushes the cutting wheel deeper into the cutter’s groove as shown here.
When you’ve turned it around enough times while tightening, it will simply ‘part’ from the copper pipe. This leads to one of the problems with tubing cutters: The cutter is essentially pushing through the pipe wall, so it leaves a ridge on the inside of the pipe, as shown here.
The ridge will cause a dramatic increase in flow resistance compared to nice smooth pipe. The left pipe wall edge is thicker after cutting than the piece on the right.
You want to remove this ‘ridge’ – most pipe cutters have hardened steel ‘blade’ that can do this.
You simply put the blade inside the pipe and turn it around until the ridge is scraped out. You can use a utility knife or other sharp tool, but be careful if they are not hardened and tough, because we are talking about metal cutting here and metal is bad for your eyes. Always wear safety glasses! It may look funny to some, but I would rather look funny than have no ability to look! If you don’t believe me, just ask my brother who cut the iris of his eye when he was a kid – no fun! Descending soapbox now…
Soldering: This is what connects these bits together. Now I’ll go through what it takes to solder together copper pipe and fittings. (Note: I’m not a plumber, but I play one around the home, so if you have any corrections or enhancements to this, let me know.)
OK – so we have our copper pipe bit and a fitting – now what? Clean it up! One key factor in a good solder joint is clean metal. Most, if not all, metal has an oxide coating on the outside as it comes from the store. Copper especially gets that flat, tarnished look, so we need to clean it – I prefer steel wool. A lot of plumbers use emery cloth or even sandpaper, but the effect is the same – nice and shiny copper!
Here I have my copper pipe bit all shined up with steel wool.
Don’t forget to clean out the receiving fitting.
Now apply a liberal amount of flux to both parts.
Assembled, you should have flux oozing from the two parts like this.
Here is the type of solder and flux I used for this.
And here is my trusty Butane torch. I bought the torch, flux, and solder together as a kit.
Now of course, don’t forget the safety gear; here’s what I use along with a heavy denim apron. I also wear latex gloves under the leather gloves to keep the flux off my skin. Did I mention flux is an acid, that’s how it etches the metal for a good seal. On to soldering…
A tip a good friend of mine told me years ago was to make the flame from the torch small. My friend had worked in a machine shop that did fabrication and had learned to weld and braze from an old master-welder. Here the flame is about ¾ inch – just fine.
Next we heat the parts up. Notice I am holding them in a vise – a good idea because these parts are going to get really very hot! Try to clamp the part as far away from the parts as possible – I’m using the valve’s handle here – this is to avoid having to heat the entire vise along with the parts. What happens is the clamping device absorbs heat from the parts, so use only metal clamps.
When it gets good and hot, you remove the flame and touch the solder to the joint – where the parts meet. The parts are hot enough if the solder melts from their heat. I use a wet sponge to clean off any excess melted solder before it cools, but that is not required.
There is a difference between soldering and brazing.
Soldering involves a bringing together or metals using mixtures of lead, lead and silver, silver and copper and so forth. It is usually low-temperature, but (as in the case of much high quality jewelry work in silver and gold) can also be in high-temperature ranges.
Brazing refers to a joining of metal using brass mixtures as the joining material. This is almost always a higher-temperature operation and usually involves the use of an oxy-acetelyne torch as the heat source. A brazed joint is much, much stronger than a common lead-soldered join. As an example, it is the classic method used to join metal bicycle frame components.¹
Here is what a good joint looks like. Well this is as good a joint I can make. I’m sure a professional plumber could do better.
And last but not least, I’ll talk briefly about the types of valves I’ve used lately: Ball-valves and Gate-valves. Being an engineer, I also have a fair knowledge of many other types of valves, but I haven’t spent the money to buy any others – yet.
This is a gate valve – good for stopping flow (a valve’s main job) and also not too bad for throttling flow, but it has high flow resistance. By throttling, I mean simply setting the valve partially open. This is useful in regulating flow.
Here it is full open.
Here it is partially closed. You can see the ‘gate’ closing across the valve’s flow path. You have to turn this valve’s ‘knob’ many times to get it to close, which gives you more flexibility in how open it is. The flow channel on this particular valve is also unobstructed when the ‘gate is up’ or the valve is fully open.
Another popular valve is a ball-valve, like this one in the middle here (red handle).
A ball valve has a ball in the center that has a hole in it. It can be opened or closed by a simple 90-degree turn of the handle. Some times these valves are referred to as ‘shut-off’ valves.
As the ball is turned, the hole is partially obscured by the valve’s body, as shown here. This particular valve has a good flow channel when open but is not so good for throttling because it really only has a limited control range of one quarter turn.
Well, that is all I have at the moment on those subjects, but if you have any questions, feel free to email me and I’ll see if I have an answer.
¹Many thanks to Peter Loft for this explanation.
Readers sent in some tips that I think are valuable and I wanted to pass them along to others:
“I just wanted to point out a couple tips that a plumber taught me that will help out when soldering copper.
Apply the heat to the fitting end instead of the joint that is being soldered; solder is drawn to the heat and this will pull the solder into the joint better. Apply heat all around to heat the joint until it is hot enough to start to melt the solder – you can tell it is close when the flux starts to boil, then heat one side and apply your solder to the opposite side.
Once the solder starts to melt, remove the heat and apply solder till it drips from the joint – it is full at this point. Wipe it with a wet rag toward the joint; this not only smooths out the joint but removes any flux that remains, which will turn your joint green.
When soldering valves, they should be open to prevent overheating. Gate valves aren’t as bad as valves that use rubber washers to seal but to be on the safe side I always remove the stem and seal.”
“I just finished reading your article on OCers about plumbing tips and how-to. I enjoyed it and picked up a few tips along the way. My only comment is on the section on the valves — particularly the gate valve.
Although pressures involved in most people’s projects reading that article would probably be pretty small, using a gate valve to throttle flow is usually not recommended. I am not a plumber, but I have years of experience in the hardware industry and have found that under pressure, a half-open gate valve has a habit of leaking at the stem, due to the small concave in the ‘gate.’ Fully closed or fully open valves seal and don’t have this problem.”
“Just a small comment on your preparation of the pipe before soldering:
Steel wool is really not the best thing to be using for preparing the pipe.
When you rub something against something else, small bits of each are
transferred between the parts…in this case, you are depositing a nice layer of steel into your copper.
You can clean it all you want, but some steel will remain regardless what you do. This can weaken your joint and cause accelerated corrosion. None of this is a good thing – best to use inert sandpaper for this task.”
“Thanks for the feedback! I never thought about the steel wool leaving
residual ‘bits’ that would affect the joint, good point! I now use a
circular wire brush device that was made for cleaning 1/2″ pipe. Using
sandpaper was actually recommended to me by me plumber neighbor, but I like
the wire brush tool. I don’t think that the wire brush tool leaves metal
residue. Do you know if it does?”
“Anytime you rub dissimilar metals together there will be some transfer. Best would be if you are using copper is to use sandpaper…if you really like using a metal brush I would recommend using a copper brush as opposed to the
standard steel; you could probably find one at www.mcmaster.com or any
good hardware store.
Personally I prefer sandpaper for copper, since it is so soft you can end up taking too much off and leaving a loose joint when you
use a metal brush. For aluminum, I use an aluminum brush…most of the AL
alloys in use are harder than copper…and of course, I use a steel wire
brush for steel or brass piping.”
Thanks to all for taking the time to add some helpful tips!