How Do You Put the Plumbing Together

Connections between pieces of copper tubing are made with special fittings and solder, as everyone knows. Plumbers, fix-it men and do-it-yourselfers call it "sweating" joints. Copper pipe, of course, is soft and easy to cut. You can use either a hacksaw or a small tube cutter which leaves you with a perfectly square end.

To sweat a joint you'll need four things: (1) some steel wool or emery paper, (2) flux, which is a paste that looks like Vaseline, (3) solder wire, and (4) a heat source — usually a propane torch. These things can be found at any hardware store. It's best to use regular 95-5 lead-tin solder (the type without a flux core), and acid-type solder.

Making a good leakproof joint is easy. Clean the end of the tube to be connected and the inside of the fitting thoroughly with the steel wool or emery paper. You just have to get the surfaces shiny. Don't sand them down too much or you'll destroy the tight fit. This should be done immediately before you smear on the flux. (If you wait even as little time as an hour before soldering, the surfaces will have time to oxidize again, and you may not get a true bond.)

Gse your finger to apply a generous film of flux to both surfaces, and fit the joint together. Now heat both the end of the tube and the fitting, while you touch the end of the solder wire to the joint. (Try not to get the flux so hot that it starts to sizzle.) Be sure to heat the connection thoroughly on both sides.

When the temperature of the copper is right, the solder will suddenly melt and flow evenly into and around all sides of the joint. If you're doing this for the first time it may seem like magic to you, since the solder even flows uphill as a result of the strong capillary action created by the flux. If everything has gone well, you should have a perfectly watertight joint (Figure 74).

Don't be stingy with solder. It's cheap, and if you drip a little on the floor you won't have lost that much. A drippy joint, where too much solder has been used, is better than one where there's too little — even though it may not look quite so professional. With practice you can learn to wipe the joint quickly with a rag before the solder has set up. But be careful at first not to burn yourself.

One of the trickiest places to make plumbing connections is immediately under the roof. Here you have to work with the torch close to the rafters and roofing — which can be a fire hazard. It might be a good plan to stick a piece of asbestos or aluminum flashing temporarily between the joint and the wood so you don't burn the house down with the propane torch.

Automobile radiator hose and hose clamps, by the way, can get you out of some tight plumbing jams. These might be useful when you're making those connections through the roof to your header pipes (Figure 75).

Once everything is together, you should test your system for leaks before you run any fluid through it. It's virtually impossible to solder or resolder lines that are filled with water. The water

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Figure 74. Copper tubing can be cut with a hacksaw, but you'll do a neater job if you set the tube in a pre-made "jig" first (a). A small tube cutter (b) is a fairly inexpensive tool, and is easy to use. It makes a perfect cut every time. Before a connection is made the outside of the tubing and the inside of the fitting have to be cleaned with steel wool or some fine abrasive paper. This is done best with a rotary motion (c). After the flux is applied, the joint should be fitted together and heated. Don't try to heat the solder wire directly. It will melt into the joint whenever the copper has reached the right temperature.

Figure 74. Copper tubing can be cut with a hacksaw, but you'll do a neater job if you set the tube in a pre-made "jig" first (a). A small tube cutter (b) is a fairly inexpensive tool, and is easy to use. It makes a perfect cut every time. Before a connection is made the outside of the tubing and the inside of the fitting have to be cleaned with steel wool or some fine abrasive paper. This is done best with a rotary motion (c). After the flux is applied, the joint should be fitted together and heated. Don't try to heat the solder wire directly. It will melt into the joint whenever the copper has reached the right temperature.

Figure 75. High-temperature rubber hose — car radiator hose — can help you make some of the more difficult connections in your system. One'of the hardest places to solder is directly under the roof rafters. This is the easy way out, but use it as a last resort. Leaks can be a problem at these joints. An easy solution is to use threaded connections with Teflon pipe dope here. This stuff is normally used to seal joints in freon lines for refrigeration systems. (Radiator hose, of course, should be insulated like all of the other tubing.)

cools the surfaces too much to allow the solder to flow properly. Nothing is more annoying than having to drain a whole system and start all over again if you discover one leak.

The easiest way to test for leaks is to use air pressure. Thread a small "snifter valve" — a small fitting to which a hose can be attached — into a 1/8 inch tapping anywhere in the lines. (This can be done at any special tee that has a threaded hole to accept a gauge, thermometer or air vent fitting.) Attach the air pump hose to the snifter. Pump the lines full of air to a pressure of 20 psi, and then paint each joint with a mixture of soap and water. Check every connection for air bubbles, and resolder any one that looks suspicious. Once there are no air bubbles and the system has held 20 pounds of air pressure for an hour or so, everything is probably fine and you can remove the air pump.

How do you fill the system for the first time? Rent or borrow a centrifugal pump, jet pump or sump pump. Open all the valves in the lines — if you have them — and connect the pump hose at the boiler drain in the base of the system. Once fluid has been pumped in and circulated through the system at a pressure of 15 to 20 psi, all valves can be closed gradually, and the hoses for the centrifugal pump removed. From then on, your regular pump (or the thermosyphoning effect) can handle the circulation (Figure 76). (More on regular circulation pumps in Chapter 9.)

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