Ameriform Inc. has earmarked $7.5 million to expand its thermoforming, extrusion and rotational molding operations in Muskegon, Mich.

The private firm is adding two more vacuum forming lines to meet growth in a range of thermoforming markets, said Ameriform CEO Tom Harris in a phone interview. Also on tap for completion in early 2015 is more sheet extrusion capacity, which Ameriform uses in-house and sells to the marketplace.

“We’re trying to get another 10 million pounds of capacity in extrusion,” Harris explained.

The next expansion phase will begin in summer 2015 and will add more rotomolding capacity to the firm’s two current rotomolding lines.

Ameriform’s sales of watercraft such as kayaks and canoes marketed by its Sun Dolphin division are growing to big-box sporting goods outlets. Another key market is portable rest rooms handled by its Five Peaks Technology LLC division. Other large products made by the company range from hunting blinds to dock floats. Most production is for proprietary lines although Ameriform also will custom form or rotomold large components. Expansion should help it diversify into new markets like playground equipment and sleds.

It now employs about 260 but expects to add 60 by early next year as it relocates some production to a leased facility in Muskegon. Harris says the firm now manages about 200,000 square feet of space, including leased space, for manufacturing and other functions. The rotomolding expansion could add another 25 jobs.

Ameriform mainly processes polyethylene but it can also form and mold ABS, polystyrene and polypropylene. Its rotary vacuum formers can handle molds up ten feet wide and 20 feet long with a four-foot draw. Its twin-sheet and pressure forming rotary presses are up to six feet by ten feet. Its extruded sheet production can be as thick as half an inch.

Ameriform was founded in 1988 by Kenneth Harris, father of Tom Harris. Three other Harris siblings also have positions in the company. The family firm did not disclose annual sales.