In the video above, we demonstrate how we used the Wachs Cold Cutting Machine (www.ehwachs.com) to cut 48” pipe for our 2020 Donjon Dry Dock Project on Lake Erie. The dry dock is used to build, repair, convert, dry dock, and repower ships. It is one of only two dry docks on the Great Lakes capable of docking 1,000 ft vessels. This project required the replacement of 20” and 48” discharge piping on four pumps in the dry dock. Steamfitters Apprentice Eric Holcomb talks about the overall pipe cutting process. *Social distancing as recommended by the CDC was practiced throughout the video’s creation.
What Are Cold Cutting Machines and Why Use Them?
Cold cutting machines, also called “air cutters,” have the ability to cut through pipe without using a flame or torch, i.e. hot cutting. There are many reasons for the development and use of this process. These include:
- No HAZ (Heat Affected Zone). HAZ can occur when pipes come in contact with high temperatures like those produced from acetylene torches.
- Prevents Warping. Heat can cause large diameter pipes like the one above to warp and lose their perfectly circular shape. Cold cutting prevents this from happening.
- No grinding necessary. While torch cutting tends to yield a faster cut, it also requires the newly cut edges to be ground down to be welded cleanly.
- Highly accurate edge. The Wachs Cold Cutting machine we used in the video above provides near perfect accuracy and can both cut and bevel at the same time, creating a perfectly machined edge that saves time when welding. On a 48” pipe like the one shown in the video, if the cut is as much as 1/8th of an inch off from top to bottom, it can throw the entire pipe assembly off.
Spaeder’s Experience with the Wachs Cold Cutting Machine
The Wachs Cold Cutting Machine utilizes a split frame rotating ring that fits around the pipe. When the ring rotates, it removes small amounts of material little by little until the cut is complete. It took us about an hour of setup time and an additional 30 minutes to perform the cut. While this may seem like a lot, we saved time by not needing to do additional weld prep later.
Once the pipes were cut, we completed the primary welding in our shop before sending them out to be painted. Some field welding was required on-site at the dry dock for final installation. Because large welds can take a long time, we used a technique called “brother-in-law” welding, where two welders both start at the bottom and work up the sides simultaneously.
Click to learn more about the Donjon Dry Dock Project.