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Tech Tip

Marelon® 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) then why go through the trouble, added labor and expense of replacing it.

Marelon® Ball Valves (MF 850 & 849 series) can and have been installed on bronze thru-hulls for years. Even some new 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 such as Grady-White Boats are using Forespar® Marelon® "93" series Integrated valve systems on bronze thru-hulls without any trouble.

Tips:

• 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.