ADHESIVES

TWO MAIN INGREDIENTS – RESIN – GLUE SOLID SOLVENT – KEEPS LIQUIFIED UNTIL APPLIED

ADHESIVES How does glue work? Specific adhesion - results from strong molecular attraction between the wood and the glue and for this to occur, the adhesive must penetrate the wood cells and "wet" the fibers. Cohesion - the force which makes the glue stick to itself. This is the solid glue "line" in a joint. It is the strongest when the two pieces to be joined are machined so they mate as closely as possible

ADHESIVES HOW DO ADHESIVES CURE? SOME HARDEN (SOLVENT EVAPORATES) SOME CHANGE CHEMICALLY (EPOXY) SOME HARDEN AS THEY COOL (HOT MELT GLUE)

ADHESIVES WHAT IS MOST IMPORTANT ABOUT GLUES? WHEN WORKING WITH GLUES IT IS IMPORTANT TO KNOW ITS WORKABILITY AND ITS DURABILITY. YOU NEED TO KNOW HOW TO WORK WITH IT, AND YOU NEED TO ENSURE THAT ITS DURABILITY WILL BE STRONG ENOUGH FOR WHAT YOU ARE BUILDING.

ADHESIVES WORKING PROPERTIES SHELF OR POT LIFE (HOW LONG BEFORE IT GOES BAD) OPEN ASSEMBLY TIME (THE TIME YOU HAVE TO APPLY THE GLUE) CLOSED ASSEMBLY TIME (IN CLAMP) (DRYING TIME) CURE TIME (TIME UNTIL THE GLUE REACHES ITS FULL STRENGTH) SANDABILITY WORKING TEMPERATURE RANGE STRENGTH

TYPES OF ADHESIVES Hide Glue Polyvinyl Resin Glue (PVA) white glue – longer open time, harder to sand Aliphatic Resin Glue (Modified PVA) yellow glue – shorter open time, easier to sand Polyurethane glue – Gorilla Glue cyanoacrylate glue (super glue) Contact Cement water based 3M Fast Bond 303M Fast Bond 30 solvent based 3M Scotch Brand3M Scotch Brand

ADHESIVES Hide Glue Hide Glue (ANIMAL GLUE) – is made of collagen from the skins, bones, tendons, and other tissues, similar to gelatin. It works well as an adhesive. Hide Glue (ANIMAL GLUE) – SHELF OR POT LIFE – Long shelf life, almost indefinite in the right conditions OPEN ASSEMBLY TIME – short to long depending on how much water was added CLOSED ASSEMBLY TIME – Long, as the glue dries from evaporation CURE TIME – long, due to the slow evaporation of water from the glue SANDABILITY – excellent, this glue also works well with finishes WORKING TEMPERATURE RANGE – resistant to hot and cold STRENGTH – strong, this glue has been used to make furniture and instruments for thousands of years.

ADHESIVES Wood Glue Wood Glue is the industry standard for woodworking. A ready-to-use aliphatic resin adhesive with outstanding strength. SHELF OR POT LIFE – 1 to 2 years OPEN ASSEMBLY TIME – 5 to 10 minutes (high initial tack) CLOSED ASSEMBLY TIME – 30 minutes to 2 hours CURE TIME – 24 hours SANDABILITY – excellent WORKING TEMPERATURE RANGE – 10C to 40C, wood glue is affected by extreme cold and hot temperatures STRENGTH – Very strong, the glued joint is often stronger than the wood itself

ADHESIVES Polyvinyl Resin Glue PVA glue is your typical white glue that we have all used in school. It is similar to wood glue in setup time, but lacks strength. SHELF OR POT LIFE – 1 to 5 years if it is stored correctly OPEN ASSEMBLY TIME – 10 to 20 minutes (moderate initial tack) CLOSED ASSEMBLY TIME – 50 minutes to 3 hours CURE TIME – 24 hours SANDABILITY – moderate, does not sand as well as wood glue WORKING TEMPERATURE RANGE – 10C to 40C STRENGTH – Not strong enough to be used in woodworking joints. It is mostly good for arts and craft where high strength is not needed.

ADHESIVES Polyurethane glue Polyurethane glue is moisture activated and expands to fill gaps. A popular brand of this type of glue is Gorilla Glue. SHELF OR POT LIFE – 1 to 2, once opened it needs to be sealed very well OPEN ASSEMBLY TIME – 5 to 10 minutes (high initial tack) CLOSED ASSEMBLY TIME – 1 minutes to 2 hours CURE TIME – 24 hours SANDABILITY – moderate WORKING TEMPERATURE RANGE – Is not affected by extreme cold or hot STRENGTH – Very strong, this glue will work well as a wood glue

ADHESIVES Cyanoacrylate Glue cyanoacrylate glue, or as we know it “super glue” is moisture activated and offers a near instant bond. This glue works best with prepared smooth surfaces. SHELF OR POT LIFE – 1 month to 1 year depending on storage OPEN ASSEMBLY TIME – mere seconds to 10 minutes (very high initial tack) CLOSED ASSEMBLY TIME – 10 minutes to 1 hour CURE TIME – 1-4 hours SANDABILITY – moderate WORKING TEMPERATURE RANGE – Is not affected by extreme cold or hot STRENGTH – Very strong, but this glue is too thin and does not fill voids. Wood is too porous a product for this glue.

ADHESIVES Your brain after using water based contact cement

ADHESIVES Your brain after using solvent based contact cement

ADHESIVES types Hot Melt Glue

ADHESIVES types – hot melt

ADHESIVES clamping THREE REASONS TO USE CLAMPS: DRY FIT KEEP PARTS ALIGNED WHILE GLUE CURES MOST GLUES REQUIRE PRESSURE BRINGS MEMBERS INTO CONTACT SQUEEZE OUT AIR THIN OUT GLUE –NO THICKER THAN A PIECE OF PAPER

ADHESIVES clamping Clamp Layout – 1” from edge and 8” to 10” intervals

ADHESIVES clamping HOW MUCH PRESSURE IS REQUIRED? Low Density Woods – 100 to 150 PSI PINE Medium Density Woods – 150 to 250 PSI ALDER High Density Hardwoods – UP to 300 PSI RED OAK HPL – 30 to 80 PSI Veneer – 100 to 125 PSI

ADHESIVES clamping How Much Pressure Can Be Exerted By A Clamp? Wood Screw Clamp – 800 to 1000 # Bar Clamp – Up to 2000# C-clamp – 1000# Spring Clamp – 25#

GLUING AND WOOD MOVEMENT