Fiberglass Manufacturing Methods
Meeting the demand of today's high technology presents many challenges in the fiberglass industry. Palmer Mfg. specializes in meeting these demands by offering our customers numerous types of resins that are designated for the type of application needed; along with different types of orientations, diameter, finishes and resistance to corrosion that will aide in the manufacturing of the proper tank to fit each one's needs.
Take those variables and combine them with the three different fabrication methods and the result is hundreds of different combinations.
The three techniques used are: hand lay up, chop spray and filament winding.
Hand lay up and chop spray can each be referred to as Contact Molding, which follows ASTM 4097. Hand lay up involves manufacturing the tank by hand. This is a low to medium volume method for small or extremely large products. The process involves manually placing fiberglass material on a mold and applying resin by pouring, brushing or spraying. The use of thermosetting resin allows for the product to cure at room temperature.
Chop sray involves a method where continuous strands of fiberglass are fed into a chopper gun which chops the fiberglass into 1" to 2" strands. The strands, along with the selected resin, are sprayed onto the mold. Then a roller is used to force out the air and help put resin into the glass.
The third technique, filament winding, involves wrapping multiple, continuous strands of fiberglass onto a rotating mandrel. Resin is applied by either spraying or pulling the strands through a resin bath. Special machines are capable of laying down strands in a predetermined pattern to increase strength along the stressed axis. Tanks are generally wound at an angle of 90 degrees to the axis, hoop winding. Filament winding is commonly combined with the chop spray method. When this is done, a monolithic tank wall with superior strength and liquid retention is produced. This process follows ASTM 3299.