This is Part 3 of the Oregon City main line repair. Parts 1 and 2 covered the high-pressure drain-down and the copper pipe prep sequence — deburring, polishing, and sanding until the surface was ready for a fitting that will not leak. This part is the install itself.
The fittings used on this job are pressed copper, installed with a Milwaukee ProPress tool. If you have never seen one in action, the 2-inch crimp on camera at 3:55 is worth watching. It is fast, it is mechanical, and it is permanent.
What a Slip Coupling Is and Why It Was Used Here
A standard copper coupling has stops — internal shoulders that prevent the fitting from sliding more than a set distance onto the pipe. That is useful for new construction where you are working with full pipe lengths and making clean joints. It is a problem on a repair.
When you cut out a damaged section of pipe in place, you need a fitting that slides fully onto the existing pipe without stops, so you can position it over the repair gap and slide it back into place. That is a slip coupling. It has no internal stops, which means it can travel the full length of the fitting body onto the pipe, clear the gap, and then be slid back to center and marked before the press.
On this job, Nate used a T fitting at the branch point and slip couplings to complete the connections on either side. The T went in first, the pipe piece was cut to length for the middle run, and the slip couplings were slid on, centered by hand, and marked around the pipe before the ProPress came out. Getting the mark right is what positions the fitting correctly — too far either direction and the fitting shoulder misses the press zone.
How ProPress Works on Copper Pipe
A traditional copper sweat joint uses flux and solder applied with a torch. When done correctly, it creates an excellent bond. It also requires heat in the trench, which means fire near wood framing, insulation, or dry soil depending on where the pipe runs. It requires a completely dry pipe interior — any residual moisture turns to steam and pushes the solder out of the joint. And it requires the plumber to hold a consistent temperature on the fitting while feeding solder, which takes skill and time.
ProPress is a press-fit system. The fitting has a built-in EPDM or stainless steel sealing element inside the socket. The jaws of the ProPress tool close around the fitting and apply a controlled mechanical force that deforms the copper around the sealing element, creating a permanent watertight joint. No torch. No flux. No solder. No dry pipe requirement.
On a 2-inch main line where you have just drained a large volume of water and worked in a wet trench, the no-dry-pipe advantage alone is significant. There is residual moisture on every surface. A torch joint in those conditions risks a cold joint or a steam pocket in the fitting. A press fitting does not care about moisture — the mechanical connection is the seal.
The Milwaukee ProPress M18 handles copper through 4 inches in diameter. The 2-inch jaw Nate uses on this job takes about three seconds per press cycle. The connection is rated for 200 psi working pressure on water systems — well above the residential supply pressure in Oregon City, which typically runs between 60 and 80 psi.
Pressurizing the System After a Full Drain-Down
After the fittings were pressed and the connections checked, the system needed to be slowly brought back up to pressure. Nate explains this clearly in the video, and it is worth understanding if you have ever had a repair done on your main line.
When a pressurized water system is fully drained, air fills the space the water occupied. Every section of pipe between the closed valves is now holding air at low or no pressure. When you reopen the valves, incoming water has to push that air out through the system. That air is compressible. Water is not.
If the inlet valve opens too fast, the water column hits the air pockets hard. At each turn in the pipe, the velocity of the incoming water transfers into pressure on the pipe wall — what plumbers call water hammer. On a 2-inch main feeding both a house and an irrigation system, with smaller diameter pipe downstream, a fast fill can push pressure spikes through the whole run. That is how fittings fail, valves crack, and the repair you just made gets tested in the worst possible way.
Slow valve opening lets the air bleed out gradually. The system fills from the supply end, air exits through any open fixtures or hose bibs downstream, and pressure equalizes without a surge. Nate brought the system up slowly, confirmed no leaks at the repair, and called it done.
Pipe Repair in Oregon City and Clackamas County
This three-part repair — drain-down, prep, and final install — is what a correctly executed pipe replacement on a main line looks like. Every step matters. The ProPress seal is only as good as the surface prep underneath it, and the system test at the end is what confirms both.
Principled Plumbing handles pipe repair and main line work across Clackamas, Multnomah, Washington, and Marion counties, 24 hours a day. Call (503) 919-7243 to schedule.
Sources and Further Reading
- Viega ProPress System Technical Data — Technical specifications for press-fit copper fittings including pressure ratings and installation requirements.
- Milwaukee Tool — M18 ProPress — Manufacturer specs for the ProPress tool including jaw sizes and cycle times.
- Copper Development Association — Joining Methods for Copper Tube — Industry reference covering both sweat and press-fit joining methods for copper pipe systems.
- Oregon Building Codes Division — Plumbing Specialty Code — Oregon code governing approved joining methods for copper water supply pipe.
