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Adhesives 1. PURBOND high adhesive strength
TECHNICAL DATA Purbond is a moisture curing, 100% solids, polyurethane adhesive. It reacts with surface moisture on any substrate, especially semiporous materials, which initiates its curing reaction. In the process of this reaction, Purbond foams and expands slightly, forcing its way into gaps, unevenness, or pores on each of the mating surfaces, thus enhancing the contact area of the joint: It has high shear strength and is creep resistant. Purbond can be used for bonding most materials including timber, plywood, fibre and particle boards, foamed plastics, concrete, even metals. While a strong bond will be formed to most substrates, it may not be structural with all materials. The bond is stronger than all timbers softer than pine and oregon, especially Western Red Cedar, and breaks the timber grain of them. Harder timbers will be bonded with equal strength, but the glue line will break before the timber. Purbond is recommended for wooden boat building applications including both timber laminating and cedar strip planking, where its ease of use will be particularly appreciated. It is suitable for all interior and exterior joinery and fitting out, and wherever surfaces are imperfectly mated. It is not recommended for gap filling of open joints, where the glue can expand out of the joint, or for joints subject to forces of peel or direct tension. For such applications, use Bote-Cote Epoxy adhesives. PREPARATION AND APPLICATION Surfaces to be bonded must be sanded, clean, and free from dust, grease or other contaminants. Timber and concrete generally have adequate surface moisture to initiate cure. Other dry surfaces may be dampened with water before application by wiping with a damp cloth. Apply Purbond directly from the bottle to one surface only. Spread with a scraper to a thin layer, then join and lightly clamp the parts. Application rates will vary with the roughness of the surface. On an average surface, coverage will be 200 - 300 ml per square metre. Clamps may be removed when the exudate is hard, generally after 2 - 3 hours unless temperatures are very cold. At temperatures below 10 deg C, allow 5 - 8 hours for cure. Some adhesive will expand out of the joint. It is best left.to harden, and cut off or sanded after it has cured. Purbond sands easily without clogging the paper. It does not blunt cutting tools such as chisels and planes. PURBOND FOR CEDAR STRIP PLANKING Purbond is especially useful for the Strip Planking method of boat building, and great efficiency will be obtained by using it with Quickstrip profiled strips. Assemble Quickstrip planks onto the boat with the tongue uppermost. Place each fresh strip in a glueing jig with its groove uppermost, and simply run a bead of Purbond along the groove direct from the bottle. Spread the bead out into the groove with a suitably shaped wooden spatula. Then flip the strip over, and mount it onto the tongue of the previously fitted strip. Fasten at each. station in the usual way, nailing into the upper half of the strip to force it down onto the station. STORAGE AND HANDLING Purbond is moisture sensitive, and containers must be kept sealed after use. If left unsealed, a skin may form, but the rest of the product will remain useable. Shelf life is at least one year. Always wear rubber gloves when using Purbond. Contact with the skin will cause temporary blackening which cannot be removed by washing. Prolonged contact may induce allergenic reactions such as rashes or breathing congestion in sensitive people. 2. LAUXITE RESORCINOL
TIMBER ADHESIVE Lauxite is prepared by mixing with powdered hardener in a 4:1 ratio, and gives a pot life of 3 hours to 1.5 hours at temperatures between 15 and 30 deg C. Resorcinol adhesives require high clamping pressures, typically 1.4 MPa (200 psi) for hardwoods and 0.7 Mpa (100 psi) for softwoods. Press times range between 6 and 3 hours at temperatures of 20 to 35 deg C. Lauxite storage time exceeds 12 months at 25 deg C.
non-critical easy
to use 1:1 ratio by volume - simply mix two equal scoops Surfaces to be bonded must be freshly sanded with coarse grit (40 or 60 grit) abrasive, and be free from dust dirt grease or oils. MEASURING AND MIXING Equal volumes of Parts A and B should be mixed thoroughly until colour is uniform. Measure out equal volumes in graduated containers, scoops, etc, or for small batches use equal sized blobs on a mixing board. Epox-E-Glue should be used within 30-40 minutes of mixing. APPLICATION Best results will be obtained when both mating surfaces are coated with glue. Bring both coated parts together and maintain firm contact until the glue has set and strength has developed. Generally this will be within 24 hours, but low temperatures will retard the cure rate. Do not clamp tightly as a weak joint may result from glue starvation. If bonding porous materials such as foams, concrete, timber end grain, etc, seal the surface by pre-coating it with Bote-Cote liquid epoxy resin. This will prevent joint starvation due to the porous substrate absorbing resin out of the adhesive. FINISHING Epox-E-Glue will cure to an almost invisible glue line so is suitable for clear finishes. However it may be too opaque for use for filling larger holes etc under clear finishes. Clean up any excess glue with a scraper followed by wiping away with a solvent such as acetone. Cured Epox-E-Glue may be sanded, then painted or varnished. SAFETY Refer to safety data sheet and to BoatCraft brochure "Using Bote-Cote Safely and Effectively". Always wear disposable gloves when handling epoxy chemicals, and avoid prolonged exposure in order to minimise skin sensitization developing. Avoid contact with eyes, wash hands with hand cleaner and water after use, do not use solvents on your skin. BOTE-COTE EPOX-E-GLUE PHYSICAL PROPERTY DATA SHEET Tensile Strength
MPa 48 |