I read Peter Kenter’s article, Routing Roots (Tech Perspective, Cleaner, December 2008) with great interest, and I found that I agreed with many of the comments made by David Bradford of Shamrock Pipe Tools.
Our company, Productive Carbides Inc., is a carbide fabricator and tool manufacturer. Our comments favor cutting tools and are based on feedback from contractors working in the trenches. We add carbide teeth and wear pads to the standard 6- through 18-inch flat or concave saws used to remove roots and calcium deposits.
Saws are one inch smaller in diameter than the pipes being cleaned. Our special teeth and wear pads add approximately 1/4 inch to the diameter, so there is still plenty of clearance. The carbide increases the life of the saws by eight to 10 times. Many contractors use the specialty carbide-tipped saws to cut taps flush with the walls of the mainline in preparation for lining.
Jets are great for debris removal, but require close control to cut through roots. It can be done; high-pressure water is used to cut steel and other metals in metal shops that can position the jets precisely. We have furnished carbide nozzles with precision holes for close pressure control during cleaning, but the idea did not catch on in the field (probably too time-consuming).
We have braised carbide to chain for added life in flail chain cleaning. Many municipalities will not permit chain cleaning, as it destroys the line if conditions are not perfect. If a sewer line is broken open, an expensive excavation is usually required for repair. A few minutes with a carbide-tipped saw reduces the fracture risk.
Waterjet nozzles, steel saw cutters and chain knockers are usually available to most contractors. The selection of which to use depends on the contractor’s ability to see the root or obstruction, direct the cutter, and clear the area for inspection and recutting if necessary. Jet nozzles take the most control to direct the jet squarely onto the root. Saw cutters take less control, but even they are often moved back and forth over a joint to get it clean. The chain flail will pulverize the roots, but will possibly take out parts of the pipe if not watched closely.
The choice of the best tool, knowing one’s limitations, and the skill of the operator determine the profit from a cleaning job. Most contractors will talk about problem jobs, but are closed-mouthed about the jobs they successfully complete. Trade secrets and lack of good information cloud discussions on what really works best.
Nelson E. Wittman
Vice President Operations
Productive Carbides Inc.
Cincinnati, Ohio
