Pipe Threading, Press Tools and Battery Caulk Guns: The Basics

Your manual wins. These are general practices. When your tool's manual says something different, follow the manual.

Pipe threading principles

• U.S. steel pipe uses NPT (National Pipe Taper) threads. The threads taper about 3/4 inch per foot, so they wedge tighter as they turn in. That wedge, plus sealant, makes the seal.
• Cut square with a pipe cutter or saw.
• Ream the inside edge to remove the burr that would restrict flow.
• Mount the die head for your pipe size on a manual ratchet or powered threader.
• Use plenty of cutting oil the whole time. Dry threading tears threads and dulls dies.
• Thread until the pipe end is flush with the far face of the die (or per the die maker's mark). Too short leaks; too long won't seal.
• Back the die off, wipe the chips and oil, and apply pipe dope or PTFE tape rated for the service (gas lines need gas-rated sealant).

Press tools

Press systems (for copper, and stainless or black iron with the right fittings) join pipe with a crimped fitting instead of solder or threads. 1. Cut square and deburr inside and out. 2. Mark insertion depth on the pipe with the fitting's depth gauge. 3. Push the pipe into the fitting to the mark. 4. Fit the correct jaw for the pipe size and fitting system (jaws are not interchangeable between systems). 5. Center the jaw on the fitting bead and run the press until the tool completes its full cycle. 6. Check the depth mark still shows at the fitting edge.

Advantages: no open flame, no waiting for water to drain, fast in occupied homes. Cost: fittings and jaws are expensive, and the press must be serviced on schedule.

Battery caulk gun

1. Cut the nozzle at about 45 degrees, small at first. You can always cut more.
2. Puncture the inner seal.
3. Set the speed dial low for small beads, higher for big gaps.
4. Hold the gun at about 45 degrees and push the bead ahead of the nozzle.
5. Release the trigger; most cordless guns back off the plunger to stop drips.
6. Tool the bead with a wet finger or tool within the product's working time.