TE TI CH PS VALVES ON BRONZE THRU-HULLS “It can be done!” For years, boat builders, boat yards and repair facilities have installed replacement valves on existing thru-hulls. This is a common practice as it is less labor intensive than removing and replacing a thru-hull that has been in a boat for years. As long as the old bronze thru-hull is sound (no electrolysis or corrosion damage), it can be retained. Marelon® Ball Valves (MF 850 & 849 series) can and have been installed on bronze thruhulls for years. Some production boat builders are installing our Marelon Integrated valves on bronze and stainless steel thru-hulls as standard equipment. High quality blue-water fishing boat builders are using Forespar® Marelon® "93" series Integrated valve systems on bronze thru-hulls without any trouble. Be sure the bronze thru-hull is sound Be sure the threads are clean and all old sealant is removed Do not cross-thread! Bronze will "cut" threads if forced onto Marelon® Use adequate Teflon® pipe tape or plumber’s dope for thread sealant Be sure you do not "violate" the sealant on the thru-hull by twisting in the hull Do not over-tighten the valve. "Hand tight" is all that is needed Properly bond or ground the bronze thru-hull. It is still subject to electrolysis and corrosion, even with the Marelon® valve installed For the "Ultimate" in corrosion control and weight savings, change all thru-hulls to Marelon® as well as the valves! Note: There are a number of foreign-made bronze thru-hulls on the market. Forespar® cannot guarantee thread compatibility on these inferior thru-hulls. Forespar® 22322 Gilberto Rancho Santa Margarita, CA. 92688 Ph: 949-858-8820 Fax: 949-858-0505