Paul Neil is correct there are more modern materials available so worth looking into. I'll admit I'm a bit old school so what follows is what I've used for many years and am most comfortable with. For repairs such as this to replace wet / rotten balsa core I've stayed with balsa but also have used marine grade plywood of required thickness to match the balsa being replaced. Properly fitted and then used West System epoxy to glass in on both sides. Deciding factor for me to use plywood is if there are fasteners that will be going through the sandwich panel. If you use balsa in this case it should be potted with epoxy in the area where the bolts go through to prevent crushing when the bolts are tightened. This stays to the original design intent (strength and weight) and is cost effective. I would also look into how water got in the first place to cause the current rot and fix that issue by using butyl tape or other means. The other approach is to use foam core material (either rigid or two part liquid foam) which is how most rudders are made. I had to rebuild the rudder on a C&C 29 Mk2 to replace a bent rudder post (done by prior owner) and after installing the new post I poured in two part liquid low expansion 15 lb density foam to replace the foam I removed (damaged / wet). Once cured it is easy to cut / shape with a saw or long blade to match contour, and then epoxied new glass skin in place. Again, in areas where bolts or fasteners are going through consider potting that area with epoxy so as not to crush the foam core. This technique also works well on decks and the nice part of using a two part epoxy expanding foam is you pour it in and it will fill the entire cavity and bond well. If you google balsa core or plywood core or foam core boat deck repairs so will find some very detailed instructions and pictures of repairs done by other boat owners. Here is one example for a deck repair.... https://epoxyworks.com/index.php/replacing-damaged-balsa-core/ Good luck! Cheers James ----- Original Message -----
From: "Neil Andersen via CnC-List" <cnc-list@cnc-list.com> To: cnc-list@cnc-list.com, cnc-list@cnc-list.com Cc: "Neil Andersen" <neil.eric.ander...@gmail.com>, "Paul" <pdsax...@rogers.com> Sent: Thursday, August 9, 2018 7:28:19 AM Subject: Re: Stus-List Chain plate hull reinforcement I would talk to a good fiberglass person. Good boats these days are not using balsa coring but a synthetic that won’t rot (one way to differentiate quality on newer boats). Check out https://www.boats.com/resources/shifts-in-fiberglass/ and http://www.fiberglasssupply.com/Product_Catalog/Core_Materials/core_materials.html. Neil 1982 C&C 32 FoxFire Rock Hall, MD Neil Andersen 20691 Jamieson Rd Rock Hall, MD 21661 From: 30071455000n behalf of Sent: Thursday, August 9, 2018 6:49 AM To: cnc-list@cnc-list.com Cc: Paul Subject: Stus-List Chain plate hull reinforcement Hello all, There are reinforcing “pads” that are glassed in at the base of the small bulkheads supporting the chain plates on my C&C 29 Mk1. Under the roving there is balsa (mostly rotted) bonded to the inside surface of the hull. Is it best to replace with identical new balsa core matting or does anyone have recommendations on some other method of stiffening the hull in this location. Thanks Paul D. Saxton 29 Mk 1 Boomerang _______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray _______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
