Trade Secrets: Basic Techniques of Surface Prep for Repairs on Wooden Boats?
Learn the basic techniques! Whether you plan on bonding, laminating, filleting, fairing, or applying fabrics, the success of the application depends not only on the strength of the epoxy, but also on how well the epoxy adheres to the surface to which it is being applied.
Why is Surface Preparation Important?
“Surface preparation is one of the key basic techniques”. Richard from Wessex Resins & Adhesives follows the mantra that there are three stages of surface preparation when working with epoxy: “1) surface preparation, 2) surface preparation and finally 3) surface preparation… you can never do too much!”
How to Clean Surfaces for Epoxy Application?
Surfaces must be free of any contaminants such as grease, oil, wax, or mould release. Recommended products for cleaning contaminated surfaces include WEST SYSTEM® Epoxy 850 cleaning solvent, acetone, or a silicone or wax remover. Ensure you wipe the surface with clean white paper towels before the solvent dries. Clean surfaces before sanding to avoid sanding the contaminant into the surface.
How to Dry Surfaces for Epoxy Application?
All bonding surfaces must be as dry as possible for good adhesion. If you are short on time, to accelerate the drying, you can warm the bonding surface with hot air guns, hair dryers, or heat lamps to aid in the drying process. Use fans to move the air in confined or enclosed spaces.
Why is Sanding Necessary for Epoxy Application?
Sanding is labour intensive, but necessary. Sand hardwoods and non-porous surfaces thoroughly to obtain an abraded surface. 80-grit aluminium oxide paper should be used to provide a good mechanical key for the epoxy.
Basic Techniques: How to Remove Amine Blush?
Amine blush is a by-product of the epoxy curing process that may appear as a wax-like film on epoxy surfaces during the final cure phase. Amine blush can occur more so in damper, colder working environments. A simple remedy to treat the area affected is to wash the surface thoroughly with 855 Cleaning Solution and then wash with clean water and an abrasive pad. Dry the surface with plain white paper towels to remove the dissolved blush before it dries on the surface. After washing with the abrasive pad, the surface should appear dull. Sand any remaining glossy areas with 80-grit sandpaper.
Thankfully amine blush is water soluble and can easily be removed but can clog sandpaper and inhibit subsequent bonding if not removed, so it is important to ensure you remove amine blush early on when discovered.
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