Fusion welding process expands size of roto-molded tanks

A plastic welding system manufactured by Powercore International in Nepean, Ont. offers roto-molders the chance to build bigger tanks; as well, has a host of other possible uses in thin sheet, piping and injection molding applications.

The Powercore Welding Rod is an “electro-fusion” welding system used for joining plastic parts. It was developed about 10 years ago by president Rob Pinter and licensed exclusively to a large piping manufacturer. The license has recently expired and the company is now marketing the technology for wider general industry use.

The welding rod consists of multiple wires wound on a plastic core. An outer layer of plastic material is extruded over the core and wound wire to produce a rod approximately 3/16 in. in diameter. The rod is positioned in the area of the part to be welded using one of several possible techniques. After positioning, the stripped ends of the rod are attached to a power source sufficient to generate six amps of current per one foot of length. Total voltage requirements depends on total length of the weld. A standard 220 volt wall circuit can weld 29 ft. at once.

According to Paul Malouin, sales manager, the Powercore Welding Rod opens up a new realm of possibilities in the design and manufacture of roto-molded tanks.

“The biggest tank you can roto-mold in one piece is about 3,000 gallons,” says Malouin. “With our technology you can build tanks from welded roto-molded sections that are double that size, or even larger.”

Other welding methods only weld the outside of the surface; whereas the Powercore Rod eliminates weld weak spots by melting and rejoining the two layers through the entire width of the joint, notes Malouin. Large tanks are built by fusing multiple body sections between end panels. Multiple sections are also cheaper to transport than large finished tanks.

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