Recent content by Bob Hunt

Vinylester resin putty is compatible with polyester gelcoat... 1. To Interplastic VE8117 vinylester add Cab-O-Sil TS-720 (about 10% by weight) and stir until consistency is smooth and creamy. The vinylester resin putty can be mixed days before application. 2. To activate the vinylester resin...

Cab-O-Sil TS-720... Cabot Corporation Cab-O-Sil Division "CAB-O-SIL TS-720 Treated Fumed Silica in Vinyl Ester Resins This technical data sheet describes the use of CAB-O-SIL TS-720 treated fumed silica as a thixotropy for vinyl ester resins. This high purity silica is treated with a diethyl...

The Lenox method for fiberglass repair... Dave and Mark Lenox have used the following basic components since 1985: 1. Interplastics CoREZYN VE8117 vinylester resin 2. Hi-Point 90 methyl-ethyl-ketone-peroxide (MEKP) catalyst 3. Cab-O-Sil TS-720 4. Cook's sanding polyester gelcoat (NPG ISO)

The album "Makana repair" shows a repair that was completed last month of a catamaran keel that was damaged after a collision with a submerged cyprus stump. Absolutely no resin putty was used to fair the exterior surface. All of the fairing was carried out by molding with 1.5-oz. chopped-strand...

Thanks for the kind words. If you are planning to fill a hole in the fiberglass hull, particularly if it's below the waterline, than several layers of new laminate should also be applied to the inside surface to cover the hole. Bob Hunt

Here's how I have repaired many holes in hulls that were below the waterline. And there have been no failures. First of all, using a random orbital sander and 36-grit sandpaper produce an evenly tapered cone in the laminate. Just imagine that there is a hole in the center of the cone in the...

Lightning damage... The pic looks like typical lightning damage that entered the hull from the outside. The typical morphology is a small hole with blackened laminate and a chipped gelcoat. Sanding into the area usually reveals a black crack that wanders through the laminate and little else...

The attached pic shows actual lightning strike exit damage. Lightning exited the boat's anchor-well drain hole that is shown upper left. The typical morphological characteristics of lightning strike exit damage are: 1. Blackened laminate; 2. Fractured gelcoat surface; 3. Outward forcing of...

The Navy study omits many significant details and is not very applicable to restoring a peeled hull because: 1. the panels were cored 2. the panels were post-cured at 140* F. for eight hours. However, the study does state that the resin chosen to construct the boats in the 1980s was CoREZYN...

Here's why the relative strength of clear castings of various resins is important: 1. weak resin + fiberglass = weak laminate 2. strong resin + fiberglass = strong laminate It's as simple as that.

<center style="color: rgb(0, 0, 0); font-family: Times; font-size: medium; "> Comparison of Clear Casting Properties</center><center style="color: rgb(0, 0, 0); font-family: Times; font-size: medium; "> <tbody> <center>CoREZYN</center><center>VE 8117 & VE 8121</center> <center>WEST...

Robert, The thickness of 1.5 oz. CSM after the resin has polymerized is about 0.040". You'll need to sand the peeled surface with 36 grit to make it fair and produce a rougher surface than the peeler left. You should use mat for the initial bonding layer to the formerly peeled surface that you...

Another perspective and method... Since this is my first post on this site I'll probably make some mistakes. Please bear with me. I've been involved with fiberglass repair at the professional level for more than 20 years. I learned the trade from Dave Lenox. While I'm not a professional...