Methodology Wood Work (Lamination)
“Lamination is the technique of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance or other properties from the use of differing materials.”
A laminate is a permanently assembled object by heat, pressure, welding, or adhesives.
In Wood Work Lamination is an added layer to give surface more smooth or decorative, now a days decorative prelaminated boards are also available in the market.
Fixing Lamination On Surface:
General: The wood is a naturally occurring material, can take good polish and gives a good shine and is reasonably water resistant also. However, soft woods and man-made boards etc. need some additional coat to give these properties and is achieved by providing additional laminate over the wood surface. There are several makes of laminates available in the market. There are certain boards which are pre-laminated but laminates are also available in sheets and can be fixed on the surface.
Steps involved in lamination:
Step 1: Preparing Surface: Laminated plastic sheets of 1.0 mm thickness are recommended for a flat work surface. One can use laminated plastic of 0.8 mm thickness on vertical surfaces.
Thoroughly sand and clean the surface where plastic laminate is to be applied (Fig. 1). Remove any paint or varnish before applying the laminated plastic. Regular particle board and plywood make ideal bases for plastic laminates.
Step 2: Cutting Lamination Plastic: Following points be kept in view for cutting the laminate,
Plastic laminate can be cut with a circular saw, saber saw, backsaw/ tenon saw or utility knife. The saw blade should be a fine-tooth blade (Fig. 2). A strip of masking tape placed where the cut line is to be made helps prevent chipping and makes the line easier to see.
Always cut the sheets of laminated plastic slightly oversized to allow for trimming.
Special laminate cutting blades are available to use with utility knives (Fig. 3). Use a straightedge or a steel square to guide the knife for a smooth and even cut.
Score the sheet of laminated plastic with the utility knife. Then snap it on the scored line by lifting the shorter end and applying slight pressure (Fig. 4)
Applying Laminated Plastic: Usually, one can apply laminated plastic sheets with contact cement. Epoxy adhesives can be used, but contact cements are recommended. Fevicol SR and similar other products are available in market.
Use coarse sandpaper to roughen the surface to be covered. Clean away the sand residue with a light brush or with compressed air.
After roughening and cleaning, apply adhesive with brush onto the surface (Fig. 5) on which laminate is to be fixed. Also apply a smooth and even layer of adhesive to the back of the clean laminate sheet. Let both surfaces dry. Check the adhesive manufacturer’s advice on the label for the recommended drying time. The general rule is the adhesive should be dry to the touch. A weaker bond will result if you wait too long.
Use extreme care when laying the sheets. Remember, 50 percent to 75 percent of the bonding strength of adhesive is present in the first contact. Make sure the pieces are accurately positioned before the glued areas touch each other.
You may need to apply two to three coats of contact adhesive for the trim strips along the counter edges (Fig. 6).
You can use a regular paintbrush for applying the contact adhesive to both the back of the laminated sheet and the flat surfaces. However, in some cases, a handmade paddle of wood may be better for spreading the cement or adhesive (Fig. 7).
After the recommended drying period, you are ready to position the sheet of laminate.
Keep the sheet of laminate and cemented base apart until they are correctly positioned. On narrow strips, lay short lengths of dowel rods about 12″ (300mm) apart between the two cemented pieces until they are properly positioned (Fig. 8). The dowel rods can be moved along the surface to keep the cemented pieces apart during positioning.
When laying a large sheet of laminate, use longer dowel rods (Fig. 9). Keep the 12″ (300mm) spacing between the dowel rods. Be sure to use dowels that are at least 1/4″(6mm) in diameter. The larger the better.
When applying laminated sheets to vertical surfaces, you can usually position the glued sheets without using wooden strips or waxed paper (Fig. 10).
Step 4 : Finishing : When the laminate is correctly positioned, remove the dowel rods one at a time as the two pieces are brought together.
Use a roller to apply pressure to the newly laid sheets of laminated plastic (Fig. 11). Roll the entire surface thoroughly to eliminate air pockets and to be sure the plastic sheet is firmly attached to the surface at all points.
If one plastic laminate sheet is not large enough to cover the entire surface, one will need to make a joint. To do this, first bond the larger of the two pieces into place.
Put a narrow strip of wax paper down along the edge of the larger piece (Fig. 12). Use the dowel rods again to keep the second piece of laminate away from the cemented surface. Begin at the joint and position the second piece butting tightly against the first. A strong adhesive tape should be put joining this second piece to the first to help hold it in place.
After using the roller to firmly attach the second piece of laminate, go back and carefully lift the edge over the wax paper. Remove the wax paper and reposition the laminate. Finish by using your roller to apply pressure, working from the center of the laminate toward the seam.
You can also use a wooden block and mallet to assure good adhesion at all points on the newly laid surface. Work from the center of the surface toward the edges to work out any air bubbles that might be hidden underneath.
When using the same laminate material for edging, apply two coats of cement to the edges and let it dry thoroughly (Fig. 13). Then apply one coat of cement to the back of the laminated sheet.
Place the edge strip into position carefully, using your fingers to align the sheets along the top edge as they are applied (Fig. 14).
It is usually best to start applying pressure to the edge strips in the center of each strip (Fig. 15). Work in both directions from the center on long spans. Work short spans from end to end.
If you need to trim away surplus material or cut portions of the edging strip you can use a fine-tooth backsaw, a router or a file.
Run your hand along the edge stripping (Fig. 16). It should be slightly wider than the edge it covers. However, the extra width should be at the bottom. It must be perfectly aligned at the top.
To finish the edges on top, first allow the contact cement to dry according to the manufacturer’s directions. If only a small amount of finishing is to be done, one can use a file set at a slight angle. However, most laminate edges today are finished with routers.
There are special router blades for finishing plastic laminates. The most popular are a flush cut blade and a beveled blade. Beveled blade helps to keep the laminate from chipping along the edge.
To finish the laminate edges, begin by cleaning the base of your router. Anything stuck to the base or any burrs on the base could scratch your laminate. Putting tape on the base can help take care of this.
If you are using a bit that requires a guide, set the guide carefully. The bit should cut the edge of the laminate but not the adjoining surface. It is always better to take off a little and make a second pass than to take off too much the first time.
Remove any surplus contact cement with a special solvent. You can use nail polish remover for this purpose.