Vacuum veneering and lamination doesn’t always require professional equipment costing hundreds of dollars. A new hand-powered vacuum-bag system can introduce you to this professional technique easily and inexpensively.
Vacuum lamination has become a technique well known among professional woodworkers for making interesting and unique studio furniture and architectural details, but the high cost of getting started has been a roadblock for many hobbyist woodworkers. A new vacuum lamination kit originally intended for making skateboards now makes vacuum lamination easy and affordable for all woodworkers, provided their projects don’t exceed the size of the vacuum bag.
For those of us who make boxes, even medium- to almost large-sized boxes, the Roarockit Thin Air Press kit can be a doorway for exploration. The kit consists of a vacuum bag with a built-in valve, a small plastic vacuum pump and butyl rubber tape for sealing the bag. It also includes a net bag to provide air circulation around the object being laminated, so that as much air as possible can be withdrawn from the bag. It may seem at first, after the bag is sealed, that nothing is happening as you frantically work the plastic pump, but keep working. Those with experience with larger vacuum systems may be surprised that pulling the air even from such a small bag takes time. After 12 hours or more, when the valve is opened, the sound of air rushing in tells you that all that pumping was effective and the bag did its job.
The Thin Air Press comes in two sizes. The kit with a 14" x 47" bag (originally targeted to those making skateboards) sells for about $55; a new kit more conducive to general woodworking tasks with a 26" x 28" bag goes for about $60. The company will also make bags in custom sizes. Information on the full line of presses is on the company’s Web site, roarockit.com.
For those unfamiliar with vacuum lamination, it involves some very simple principles. When air is removed from the bag, it is also removed from between the layers of anything within the bag. As a result, the weight of the outside atmosphere presses parts tightly together. It’s incredibly effective and sure beats clamps, particularly for laminating curved surfaces. It also works well for applying veneers to flat panels, as it applies pressure equally across the entire surface area without distorting the shape of the underlying panel. For those of us with experience bending wood with elaborate jigs and never quite enough clamps, or veneering with a jury rig of sandbags and clamps, vacuum lamination can be an almost amazing experience.
I first experimented with the laminating kit in making limbs for archery bows with my woodworking club at the Clear Spring School in Eureka Springs, Ark., and quickly began to imagine ways it would be useful in making boxes. I designed a simple box using a curved lid to give the kit a test. This box is designed as a place to put the things that accumulate in pockets. At first glance it appears to be just a curved tray. But lifting the lid from its base reveals the box’s inner compartments. Place the lid down on its feet, and it will stand alone, allowing both the box compartments and box lid to be useful at the same time.
Making the form
To make the curved lamination, you’ll need a curved form. Roarockit suggests that Styrofoam can be used for this. But I have a large-capacity bandsaw, and because finding a piece of wood the right size was easier than going out looking for foam, I created the curved form from a single block of salvaged yellow cypress by resawing it on end (Fig. 1).
Lacking a high-capacity bandsaw and a large block of wood, you can just as easily make the form by cutting the curve in several individual pieces, then gluing them into a single curved form (Fig. 2). Here, seven curved sections of standard 2x4 have been glued up to make the form.
The curve itself is a 7½" radius arc, easily made by using a ruler to set a compass at 7½". With the compass set, just scribe an arc on your stock and cut along the line.
Cutting and assembling the veneers
While the veneer used to make the substrate of the lid/tray is solid walnut, the top layer is made up with various colors of veneer combined into a single sheet. Cut angled strips of 1/32" walnut, cherry and maple veneer, and arrange the strips in alternating colors (Fig. 3), then tape them together using high-grade painter’s masking tape (Fig. 4). Next, use a common paper cutter to cut the assembled and taped pattern into more pieces (Fig. 5). Reassemble the pieces, alternating the angles of cut to create additional interest (Fig. 6), and tape them together.
After squaring the patterned veneer assembly and trimming the edges, use a common paper punch to punch holes through the assembled pattern (Fig. 7). The contrasting veneer rounds are used to fill the holes and are then taped in place. I had no object in this but to express a spirit of playfulness, so you can skip this step if you’d like.
Laminating the lid/tray
The lid/tray requires eight layers of 1/32" walnut veneer as a substrate for the patterned veneer top layer. Cut veneer pieces to a rough size of about ¾" wider and longer than the planned final dimensions, and spread glue between the layers. A wallpaper roller makes a handy tool to quickly and evenly spread the glue (Fig. 8). I used regular shop glue, but you could use a slower-setting white glue to buy a bit more time. Stack all eight substrate layers, and top with the patterned veneer assembly.
Place the stack of veneers onto the form pattern-side up, and tape them in place to prevent shifting while loading into the vacuum bag (Fig. 9). I use a piece of scrap cardboard between the veneers and the mesh. Either wrap the workpiece in the provided mesh bag or slide it inside. Insert the mesh-wrapped workpiece into the vacuum bag and seal the end. I prefer to use a two-piece plastic tube seal used with conventional vacuum bags (Fig. 10), but the butyl tape system that comes with the Roarockit vacuum lamination set will work fine.
Place the pump on the rubber valve stem and pull the air from the bag (Fig. 11). Pumping will become more difficult as the last of the air is removed. Leave the bag several hours or overnight for the glue to dry.
Making the base
Making the compartmented base is much more in line with conventional box-making skills. I used 5/16" walnut stock for the sides, while the base/bottom of the box is made from 5/8" walnut stock that will raise the base slightly, giving it a shadow line and allowing it to “float” visually above the surface. Use a 45-degree sled on the table saw with stop blocks to control the length of cut (Fig. 12). Then lower the blade to cut only 1/8" above the table surface of the saw, and cut slots in the sides for the bottom to fit into (Fig. 13).
Use the router table to create a 1/8" tongue around the perimeter of the box bottom, shaping it as a panel to fit into the slots cut in the sides.
Use a 1/8" bit in the router table to rout for the compartment dividers to fit. Stop blocks control the travel of the workpiece to create a precise cut (Fig. 14). Use a chisel to remove the remaining space between the routed cut and the saw kerf. Make the dividers from 1/8" walnut stock, and round the top of the dividers to match the shape of the 1/8" diameter routed slots. You can do that with 1/16" roundover bit in the router table, or simply sand the top edge round to fit.
To contour the ends of the base to fit the underside of the tray, first cut the tray to its final dimensions of 5" x 9¾" and simply trace the shape of the tray onto the end piece as in Fig. 15. Then make the cut with the bandsaw and sand the curve smooth.
Use a block plane to shape the inside edges of the front and back to match the contours cut in the ends (Fig. 16).
Tape the box sides together temporarily to check the fit on the underside of the tray. With the box taped together, mark the underside of the lid/tray for the legs to fit. Trace the fit of the base on the underside of the tray so that feet can be accurately placed (Fig. 17).
Assemble and glue the box together, using plastic packaging tape to hold the corners tight while the glue dries (Fig. 18). Clamps could be used for this, but I like the way tape brings the corners in perfect alignment. To get extra force in clamping, more layers can be applied and pulled tight. Before the glue dries, be sure to check that the box is square and adjust if necessary.
Keying it up
When the box is dry, remove the packaging tape and cut slots in the corners for miter keys – sometimes called “slip feathers” – to fit. Miter keys strengthen the miter joint, and add a decorative touch in either matching or contrasting woods. A simple 90-degree jig holds the box securely in a vertical position to cut the corner slots on the table saw (Fig. 19). I cut three slots in each corner, for a total of 12, but you could cut only two per corner if you prefer.
Rip a 1/8"-thick strip of wood on the table saw to make the keys, then cut the strip into small triangles. Glue the keys in place in the corners of the box, and sand them flush with the sides of the base when dry.
The support feet for the lid/tray are simple 5/16" x 3/8" x 3" strips of walnut, curved to match the lid and beveled slightly on the bottom corners. Attach the feet to the underside of the lid/tray by applying a thin line of glue and clamping them in place in the location marked earlier (Fig. 20).
When dry, the feet can be strengthened if desired by using a drill press to bore a pair of 1/8" holes through the feet and part-way into the underside of the lid, and gluing 1/8" dowels in place.
Sand the tray and base up to 220-grit, being very careful not to sand through the patterned top.
Finish the box with several coats of Danish oil (Fig. 21), allowing each coat to soak in thoroughly and wiping off the excess between coats. Watching the beauty of the veneers emerge as the oil is applied is one of the fun parts of the project.
For a final touch, cut felt or other lining material to fit the compartments in the base.
The hand-operated vacuum laminating kit is a welcome addition to the amateur woodworker’s arsenal of creative devices. Using this simple lidded box as a starting point for your personal exploration, there’s no limit to the types of projects you can accomplish through the power of vacuum.
A 30-year maker of furniture and wooden boxes, Doug teaches at the Clear Spring School, Arrowmont, Marc Adams School and the Eureka Springs School of the Arts. He lives with his wife and daughter on a wooded hillside overlooking Eureka Springs, Ark.
Tools used in this project
Compass, bandsaw, paper cutter, paper punch, wallpaper roller, vacuum press, clamps, table saw, miter gauge, stop blocks, router table, packaging tape, square, drill press.
Walnut, maple and cherry veneers
Clear packaging tape