Bending Wood

Home , Heat bending of wood, Steam bending, Steam box

Essential Techniques for Bending Wood

Plus a Bent Wood Shelf Plan Photo by Al Parrish Instead of making a giant compass, I draw the curve by bending a thin strip of wood across the layout marks. ost of the time when a With steam bending, you need Finish nails hold the shape while piece of wood has a bend a boiler, a steam box and a way I mark the curve Mor a curve, it means trou- to quickly clamp a scalding-hot with a pencil. ble: Your stock is warped or bowed. piece of wood to a form. Then you But sometimes a bent part can add need to wait several days for the an interesting design element. The part to dry. With bent lamination After smoothing curved supports in these shelves you need only a form and a way to the fi rst piece, transform what might be plain clamp the thin strips of wood to it. rough-cut parts and ordinary into an interesting You don’t need to wait an hour or are then added and contemporary design. more for the wood to get ready to to the form. A I usually like to keep things bend and you don’t need to race fl ush-trimming simple, which to me means using like a madman to get a hot piece of bit is used in the as few parts as possible. But when it wood clamped in place. Once the router to make identical curves comes to curved parts, such as the glue is thoroughly dry, the parts for the bending supports for these shelves, I form are ready to use. form. the curves by gluing together sev- The techniques I used to build eral thin strips rather than steam these shelves can be employed bending one piece of wood. This many different ways. Table aprons technique of bent lamination is and chair backs are common uses Make an Educated Guess strips 3⁄32" thick or a dozen pieces faster and the results are more for curved parts. Once the shape I like to use the thickest strips 1⁄16" thick. It all depends on what predictable than steam bending. and size of the curve is determined, possible to minimize the number wood is used and how tight the you build a form for gluing, and of parts and glue lines. The more radius of the curve is. decide what thickness of strips to strips in the lamination however, I make a good guess at a thick- use to make the curved parts. the stronger it will be, and the ness, and resaw a piece of the mate- likelihood of the curve spring- rial to that size. I then bend the ing back away from the form will piece to roughly the curve I want. be minimized. If it’s diffi cult to bend, or I hear To get the fi nished thickness any popping or cracking noises as of 3⁄4", I could use four strips 3⁄16" I make the bend, I try again with thick, six strips 1⁄8" thick, eight a slightly thinner piece. For this project, which uses ash, I started at 3⁄16" thickness but ultimately decided to use 1⁄8" for the strips Bent to make the shelf supports. The next step is to build the form used for bending the curved parts. The shelf supports finish at 2" wide, but the laminations are glued together at 21⁄2". The extra width means I don’t have Laminations to worry about keeping all of the edges perfectly lined up during Make curved forms without getting steamed. gluing. After the glue has dried overnight, I can get a clean edge on the jointer, and achieve the by Robert W. Lang fi nal width by ripping the part on Comments or questions? Contact Bob at 513-531-2690 ext. 1327 the table saw. One more light cut or [email protected] on the jointer will remove any saw

popwood.com marks. A few quick swipes with a Now make the strips for the card scraper leave the edges ready laminations. They can be ripped for fi nishing. on the table saw, but it can be To get the 21⁄4" thickness for dangerous to work with parts the form, I used three layers of that thin, and nearly half of the 3⁄4"-thick birch plywood cut to material will be lost to the saw the inside radius of the curve, kerf. By using the band saw, the and a fourth piece as a base plate. operation is much safer and less It doesn’t matter what the form is material is wasted. I cut the strips made from; I used material that to 3⁄16" and took them down to the was left over from another project. fi nished thickness of 1⁄8" by send- I would have used particleboard or ing them through the thickness medium-density fi berboard (MDF) planer. I clamped a piece of scrap if I had found a piece of that fi rst. MDF to the planer bed to carry The radius is 5611⁄16", which the thin pieces. Because the ash I would require a long trammel to used was straight grained, I didn’t draw and cut the curve. Instead, worry about the edge grain match- I simply marked the end points ing, and cut all the strips I needed Resawing strips on the band saw is safer and less wasteful than using the and centerline of the curve, and from 4/4 stock. table saw. I cut them a little thicker than necessary, clean up the saw marks, marked off the 4" rise at the center. In addition to cutting the strips and bring them to fi nal thickness with the planer. I then drove a 4d fi nish nail at each wider than they need to be, I also of these points, and bent a thin cut the strips about 6" longer. strip of wood across them. When you glue six pieces together It takes three hands to bend at a time, they can slide around and mark the curve. If you don’t some, and each layer is slightly have someone to help you, drive shorter than the layer next to it. fi nishing nails at an angle close It’s easier to leave them long and to the points used to defi ne the trim them when you’re done. curve. With the midpoint inside MDF sled the nail, and the ends outside, the Get Ready to Glue thin piece will hold its shape. You Before attempting a glue-up, I can bend the nails to position it made a dry run to make sure my exactly where you want it. I cut the clamping method would work, curve on the band saw, being care- and that everything I needed ful to saw just outside the pencil was at hand. To form a fair curve, line. Then I used #80-grit sandpa- pressure must be evenly applied. Thin pieces can be sent through the planer on a sled, a piece of 3⁄4"-thick MDF per wrapped on a block of wood to This means a lot of clamps placed that extends past the feed rollers and is clamped to the planer bed. get the curved edge smooth. closely together. During the dry run I determined that 4" or 5" The First Part is the Pattern apart was a good spacing. The fi rst layer of the pattern is the Typically I use yellow glue for only one that requires this much most of my woodworking but bent work. The remaining pattern lamination isn’t a standard pro- pieces can be marked by tracing cess. The wood wants to straighten the fi rst one. After cutting them back out, and yellow glue is some- slightly oversize, they are attached what fl exible after it’s dry. A glue to the fi rst piece with half-a-dozen that dries more rigidly should be #8 x 11⁄4" screws, and the edges are used. Epoxy, plastic resin and reac- trimmed with a fl ush-cutting bit tive polyurethane all dry to a rigid in the router. line. I chose to use polyurethane After attaching the base plate, (Gorilla Glue) because it doesn’t the surfaces of the form were given need to be mixed before using. Polyurethane glue can be messy as it cures. I use a thin bead of glue and a couple coats of paste wax to keep I laid the strips out in order, spread it out with a putty knife to avoid this. glue from sticking to them. and put a thin bead of glue down

POPULAR WOODWORKING October 2005 the middle of each strip. I then used a putty knife to spread out the bead evenly across each strip. I stacked the strips back up, and placed them in the form. I started clamping in the center, and worked out to the ends, alter- nating right and left. Each lamination was left in the clamps for four hours to dry. After removing the bent part from the form, I scraped off the excess glue. After the last part was removed from the form, I waited another 24 hours to be sure that the glue was fully cured before moving on to the next step. I cleaned up one edge of each curved piece on the jointer. I then carefully ripped each part to 1⁄32" over the finished width on the table saw. This can be done safely Starting at the center and working out to each end, After scraping off the excess glue, one edge is evened by keeping the part flat against clamps are placed every 4" to 5" around the form. up on the jointer. Make sure to keep the curve in contact with the fence on the outfeed side of the cutterhead.

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�� Hanging blocks ��

BENT-LAMINATION WALL SHELF �� NO. ITEM DIMENSIONS (INCHES) MATERIAL COMMENTS T W L �� ❏ 2 Rear 3⁄4 21⁄2* 54* Ash From 12 supports 1⁄8" pieces �� ❏ 2 Front 3⁄4 21⁄2* 54* Ash From 12 supports 1⁄8 " pieces ❏ 3 Shelves 3⁄4 8 22 Ash ❏ 4 Hanging 1 11⁄2 13⁄4 Ash Cut from blocks larger block *Sizes reﬂ ect overage for trimming Proﬁ le Elevation

popwood.com the table and tight against the were cut and the pairs of curves the notches and are simply glued To keep the shelves aligned fence at the infeed edge of the saw were glued together. and clamped. while clamping, I placed 3⁄4"-thick blade. After this cut, I returned I marked the center 2" of each It’s a bit of a challenge to keep sticks on my bench to support the to the jointer and removed the piece and planed a fl at in this area everything lined up during assem- back edges. This is the distance saw marks with one pass over the with my block plane. I clamped bly. I started the shelves in the from the wall in the fi nished shelf. machine’s cutterhead. pairs of curves together, using notches before brushing in glue. I also made sure that the ends of scraps of wood to keep the notches Form Does Double Duty aligned and in the same plane. To make the 3⁄4"-wide x 1"-deep After the glue had dried over- notches in the supports, I put them night, I marked the ends of the back in the gluing jig. I added spac- uprights from locations marked ers below them to keep the top on the bending form and trimmed of each piece fl ush with the top the ends with a handsaw. of the jig. I added guide strips to I used my smoothing plane to the form to guide my router when fi ne-tune the fi t of the shelves to cutting the notches. To prevent the notches. I scraped all of the making two lefts and no rights, I parts and then hand-sanded them didn’t trim the ends to their fi nal with #220 grit before assembly. 3 lengths until all the ⁄4" notches The ends of the shelves slide into Guide strip

Use layout lines on the top of the bending form to attach guide strips for the router. Working from the center, I also established lines for the ends of the supports. Then I notched the curved parts for the shelves with the router.

With the fi nished part back in the jig, I lay out a 2"- long fl at at the center of each curved piece and then plane it by hand. Check the fi t by measur- ing the space between the two Notch parts at the shelf for shelf locations.

The ends of the shelves ﬁ t in the notches. Adjust the ﬁ t with a few swipes with a smoothing plane. Mark the support locations on the bottom of the shelves to keep the parts in line during assembly. The other edge is ripped on the table saw, maintaining contact with the table on the infeed side of the saw blade.

POPULAR WOODWORKING October 2005 the back uprights were fl at on the Curved parts aren’t hard to HANGING THE SHELVES surface of the bench. make, and can be both structural After a fi nal hand sanding with and visually interesting. The abil- To hang the shelves, I made two small blocks to fi t behind the top of #280 grit, I fi nished the shelves ity to make them adds to the skills the back uprights.The dimensions of the blocks aren’t critical, but with three coats of lacquer sprayed that make a well-rounded wood- they need to fi t neatly together, and be tight against the inside of the curved support. I started with blocks larger than I needed so that from an aerosol can. worker. PW I could cut them to shape while keeping my fi ngers a safe distance from the band saw blade. After cutting the blocks to shape I fi t the curved edge to the back of the shelf support. These can be fastened to a wall with Zip-it anchors (available from your local home center) after drawing a level line on the wall. The matching half of the hanger is glued to the back of each of the curved uprights. To hang the shelf on the wall, it is simply dropped in place on the hangers. – RL

Lay out the hanging blocks on a piece of wood big enough to let you cut them safely on the band saw.

Cut the curve ﬁ rst, then make two short cuts to form the interlocking joint. The last cut frees the hanger from Line up the shelves in the notches, then brush glue on all surfaces of the joint. the block.

Sticks to support shelves

The bottom half of the hanging The other half of the hanger is cleat is attached to the wall form- glued to the back of the shelf Assemble the shelves on a ﬂ at surface, making sure the ends are ﬂ at on the ing a hook. support, letting the shelves hang table. Square sticks keep the backs of the shelves in position. nearly invisibly.

popwood.com INGENIOUS JIGS Bending Wood the Wright Way Cold bending is a whole lot easier with this flexible clamping fixture.

n my mind, there are three classifica- Itions of woodworking techniques. There are many that I classify as “useful,” a small- er number that I think of as “indispens- able,” and then a very few that represent a true breakthrough in woodworking tech- nology. Bending wood is one of the latter. The ability to alter the grain direction as our imagination dictates while preserv- ing the strength inherent in a straight piece of wood allows us to create the elegant beauty of a continuous-arm Windsor chair and the inspiring sweep of a vaulted ceil- ing. We first explored our world in sailing ships with bent wood hulls, then left it in airplanes with bent wood wings. Our world would be much less beautiful and much less exciting without this simple woodworking technique. I’m currently engaged in a woodworking project designed to create a little ex- citement, and bending wood is at the very heart of it. I’m part of a group of historians and aviators who are recreating the six experimental airplanes of the Wright brothers, beginning with their model glider of 1899 and ending with the 1905 Wright Flyer 3, the first practical airplane. The frames of these primitive aircraft are a collection of bent wood parts — ribs, wing ends, braces and skids — ingenious- ly arranged to catch the wind and lift a man into the air. some of its curve. If the wood is not at- brads. They could not use glue — the ad- True Geniuses Prefer tached to the other parts in the project so hesives 100 years ago were not weather- Cold Bending as to hold the curve, it may continue to proof. A good rain and the wings would When most of us hear the words “bending relax and it will spring back even more. have come apart. wood,” we think of steam bending. The This problem plagued the Wright broth- Fortunately, we have a much larger and wood is heated briefly in low-pressure ers while they were doing their glider ex- more reliable selection of adhesives to steam to soften the lignin (a glue-like pro- periments — they calculated precise curves choose from than the Wrights. We decid- tein that holds the cellulose fibers togeth- for the ribs to fly as efficiently as possible, ed to make the bent wood ribs of our repli- er). While the wood is still hot, it’s clamped only to have the ribs relax and lose a good ca Wright gliders by laminating the parts into a bending form. The cellulose fibers deal of curvature before they could get their with a water-resistant aliphatic resin (yel- telescope to conform to the curve, and the gliders in the air. low) glue. You could also use Resorcinol, lignin cools to hold them in place. Or al- To solve this problem, they eventual- epoxy or polyurethane glue for an appli- most. In actual practice, the fibers never ly abandoned steam bending for an early cation like ours. If your project won’t be quite conform, and when you remove the form of cold bending. They arranged the exposed to the weather, you can use al- wood from the bending form, there is a parts of the ribs for their Flyers in a bend- most any good wood glue.

Photos by Chris Schwarz Photos by great deal of springback — the wood loses ing form, then nailed them together with To cold-bend wood, first resaw your

www.popwood.com INGENIOUS JIGS

3 stock into thin strips and plane it so the the thinner the strips. I use this chart as a • 8" to 12" radius — ⁄16" thick 1 thickness is even. The thickness of the jumping-off point: • 12" radius or larger — ⁄4" thick 3 strips depends to a large extent on the ra- • 2" to 4" radius — ⁄32" thick There are other factors to consider: the 1 dius of the curve. The tighter the radius, • 4" to 8" radius — ⁄8" thick species of wood, the slope of the grain (as it runs between the faces of the strips), the Help Kids Build a Wright Flyer strength you want, and the amount of The most exciting woodworking project in 100 years. springback you can tolerate. For maximum strength and minimum springback, we de- The year 2003 will mark the 100th Company (WBAC) of Dayton, Ohio, 1 anniversary of the first controlled, that addresses these concerns direct- cided to glue up the ribs from ⁄8"-thick sustained flight. On Dec. 17, 1903, ly.The WBAC is a non-profit educa- strips, although the radius of the curve was Wilbur and Orville Wright flew their tional organization of craftsmen, nowhere near 8". first powered aircraft, called simply historians and aviators who are build- the Flyer,852 feet across the sands of ing replicas of Wright aircraft, includ- Stack the strips as you will glue them Kitty Hawk, North Carolina.This ing the 1903 Wright Flyer.They will together. If you use strips that were all re- coming anniversary presents a unique build the Flyer with the involvement sawn from the same board, flip every other opportunity to get young people all of young people across America! across America excited about avia- Here’s how it works:The WBAC strip end for end to reverse the grain slope. has scripted a learning experi- Spread a thin layer of glue on the face of ence for kids ages 10 to 18 dur- one strip, lay the next strip on top of it, ing which they learn a little aviation, a little history and a spread more glue and repeat. If you’re lam- little woodworking. During this inating a large number of strips, you may experience, which takes just a want to choose an adhesive with an ex- few hours of a morning or an 1 afternoon, the kids build ⁄4-scale tended working time. ribs of the Flyer that they can Before the glue sets, clamp the lami- take home.Then the whole class nated strip in the bending form. Let the comes together to build a full- scale rib.The kids sign it and glue set up for its full clamp time. If you’re send it to the WBAC in Dayton, not sure of the clamp time, wait a full day Ohio.There, more kids under the before you remove the assembly from the supervision of accomplished A replica of the Wright Brothers’ 1900 Glider bending form. As you release the clamps, that Nick Engler built and got airborne at Kitty craftsmen, will assemble the ribs in a Hawk, N.C., in late October. replica Flyer,that’s 40 feet from there will be a small amount of springback. wingtip to wingtip. If the curve is critical (as it was for our glid- tion — and woodworking! And that’s not all.Each of the kids The Wright brothers built the who works on a rib gets to sign it.The er ribs) make the curves in the bending gliders and airplanes in their work- WBAC also invites each young per- form slightly tighter to compensate. shop in Dayton, Ohio.These machines son to make a prediction about what were largely made of wood: spruce for the next 100 years of aviation will the straight parts, ash for the bent bring.All the signatures will be pre- Making a Cold Bending Form parts and a little boxwood for the served on the replica Flyer,and the Pretty simple, huh? The only real trick to pulleys.The end result of these labors predictions will be edited and assem- cold bending is in making a form that will was that the Wrights,by virtue of bled into a large book.The completed their ingenuity and craftsmanship, kid-built Flyer and the book will be apply an even clamping pressure all along achieved the age-old dream of flight. unveiled at the Dayton International the laminated assembly. Traditional bend- The story of their woodworking Airport on December 17, 2002 (a ing forms consist of two parts, the form projects has become one of the most year before the centennial anniver- inspiring stories in American history. sary), where it will serve as a milepost (the positive shape) and the press (the neg- That said, it is becoming harder in both aviation and craftsmanship, ative shape). Both of these parts are nor- and harder for young people to ac- pointing 100 years back and looking mally cut from the same stock. Begin by quire the woodworking skills that 100 years forward. gave us the airplane and a thousand We’re looking for woodworkers to drawing the curve you want on the face of other useful and beautiful innova- serve as teachers and mentors to the stock. Cut the curve with a band saw, tions. High school shop programs are help conduct these learning experi- separating the stock into two parts. On the becoming a thing of the past. ences and to communicate the thrill Vocational schools train students for of building something wonderful to negative part, mark the thickness of the industry,which relies more and more children.The WBAC will send you bent wood part. (Tip: Use a compass like on computer-aided manufacturing. information on these experiences if a calipers, set it to the desired thickness. The old manual machine setups — you’ll just raise your hand and say “I’ll what we use every time we make a do it.” You can contact them through Follow the curve with the point of the cut or drill a hole — are no longer the Internet a www.wright- compass, marking the thickness with the being taught on a wide scale, and our brothers.org, or write Wright scribe.) Cut away the thickness on the craft will suffer if we don’t find other Brothers Aeroplane Company,Kids ways to introduce young people to Build a Flyer!, P.O. Box 204,West band saw — this will create the press. the joys of woodworking. Milton, OH 45383. The trouble with this traditional bend- Popular Woodworking has lent its Meanwhile, we’ll continue to re- ing form is that the press doesn’t compen- support to a unique program of the port on this exciting woodworking Wright Brothers Aeroplane project as it progresses. PW sate for small variations in the thickness of the laminated stock or a band saw blade

POPULAR WOODWORKING February 2001 Spread the glue on the surface of each strip Clamp the laminated strips in the bending form, 3 with a ⁄8"-32 threaded rod to draw the adhe- spacing the clamps every 3" — dead center in sive out as evenly as possible. Note that I’ve the middle of each segment of the press. I 1 placed the strip on a long scrap to elevate it drilled 1 ⁄4"-diameter holes in the form to hold above the bench.This allows the extra glue to the top face of the clamps and automatically drip over the edge. space them. that wanders a hair off the line. Conse- press. When you squeeze the laminated quently when you apply the clamps, the stock to the form, arrange the clamps in clamping pressure may not be completely the middle of each segment; this will com- Before you tighten the clamps, just snug them up even all along the form. This may result in pensate for any variation in stock thick- to hold the stock against the form.With a scrap of wood and a hammer, tap the top edges of the weak laminations or even gaps between ness or inaccuracies in the bending form strips to even them up.Then tighten the clamps the laminations when the glue dries. and keep the clamping pressure relatively until the gaps disappear between the lamina- To ensure that this didn’t happen to our even. tions. glider ribs, I designed a compensating press. Note: The plastic on the press will keep 3 After cutting away the thickness of the any glue that squeezes out from between with the teeth of a ⁄8" x 32 threaded rod. bent wood part, use the compass to mark the laminations from sticking to the can- The threads spread the glue to just the right yet another curve on the negative part, this vas. To prevent the squeeze-out from stick- thickness (about 0.005") for a strong joint one 1" larger in radius than the curve you ing to the form, apply paste wax to the form with a minimum of squeeze-out. For this just cut. Saw this curve then cut the 1"- before each glue-up. particular project, I mounted a short length thick piece into 3"-long segments. Adhere of threaded rod in a wooden handle. Be- the segments back to the negative part tem- Spreading the Glue tween glue-ups, I keep the rod submersed porarily with double-face carpet tape. Glue Just as uneven clamping pressure will re- in water to prevent the glue from drying a strip of canvas to the inside curve of the duce the strength of the lamination, so will on the threads. PW segments and cover the canvas with 6-mil an uneven application of glue. You must plastic. spread it as evenly as possible, and I’ve got When you separate the segments from just the ticket. This little trick was shown Nick Engler is a craftsman, pilot and the author of 52 books on woodworking. He’s also the director of the negative part and discard the tape, they to me by the good folks at Franklin Inter- the Wright Brothers Aeroplane Co. — you can find should be held together by the canvas like national (makers of Titebond glue). Get out more about the Wright aircraft he’s helping to the tambours of a rolltop desk. This is your rid of your glue brushes and spread the glue build at www.wright-brothers.org.

4" Individual caul segments cut to 3 the form radius plus /8"-32 threaded rod the thickness of held in place by nuts the laminated strips

3/4" Scrap wood handle Canvas glued to the radius of 1 1/4" holes for clamps the caul. Cover with 6 mil The perfect plastic after it dries glue spreader 1/8" stock milled flat and bent in jig

www.popwood.com Bend the Laws of Lignum

BY CHRISTOPHER SCHWARZ

A recent innovation lets you bend wood without steam or adhesives.

he package of wood looked everything like a mummy when T it arrived in our shop. The wood was wrapped in clear plastic, bound by plastic straps and wrapped by more plastic and cardboard. We peeled away each layer to reveal I can bend that. With Compwood, you can bend wood in ways that are surprising. When the a stick of unassuming 8/4 ash that was wood dries, it holds its shape and can be worked with standard woodworking tools. about 6" wide and 54" long. Aside from the fact that the wood was cool to the touch, it looked like regular ash. While it’s wet, you can bend the wood thickness of the work being bent. So my I took it to the jointer and planer and in almost any direction. When it’s dr y, 13⁄8" arm bow could be bent to an 81⁄4" machined it ﬂ at. I ripped off a 1"-wide it holds its shape and can be worked just radius or larger. So a 9" radius could be slice and machined that to 13⁄8" thick, like any other piece of wood. bent without a strap. just like any other piece of wood. The Compwood is also less labor- But then I put that stick into a bend- Why Try It? and machine-intensive than a typical ing form, and the wood gave up its secret I became interested in Compwood cold-lamination job. When I make cold identity. Working alone, I bent the piece when I saw it in use at Jeffrey Miller’s laminations, I typically have to sand of ash along its 13⁄8" dimension and woodworking shop in Chicago. He’s all the pieces down to 1⁄8" thick or less pulled it around a C-shaped bending been experimenting with the material for tight bends – that’s a lot of machine form with a 9" radius. In 10 minutes, to use in some of his chair designs and work. And I prefer to use plastic resin the wood was bent and clamped up. No he showed me how it works. Intrigued, I steam or heat. No adhesives. purchased some for my own chairs, and I This is Compwood, a 1988 Euro- ﬁ rst cut into this batch to make some arm pean invent ion t hat allows you to bend bows for some Welsh stick chairs. room-temperature wood around a form The Compwood appealed to me for in multiple dimensions. The lumber several reasons. While expensive, the comes to your shop wrapped in plastic Compwood allows me to make my ar m because it is fairly wet – my piece of ash bows without investing in a steam box, measured 20 percent moisture content. which I don’t have room for. Also, the material allows me to bend wood to a tight radius without a bending strap “The New Age? It’s just the old and without the risk of compression r upture s on t he in side cur ve s or delami- age stuck in a microwave oven nations on the outside curves. for 15 seconds.” How tight? There’s a formula for each Flexible terms. Compwood can be bent — James Randi (1928-) species. For ash, the smallest bending without steam or – in many cases – a bending magician, skeptic radius without a strap is six times the strap. It also can be bent in three dimensions.

■ POPULAR WOODWORKING MAGAZINE April 2011 LEAD PHOTO BY AL PARRISH; STEP PHOTOS BY THE AUTHOR

36-37_1104_PWM_CompWood.indd 36 1/26/11 3:56:21 PM glue for these parts, and it is nasty and Chris Mroz, who makes and sells messy stuff. Compwood to woodworkers and indus- While I probably wouldn’t consider try through his company, Fluted Beams, the Compwood if I made hundreds of says that I probably removed the wood chairs for a living (I’d probably invest from the form too soon. For a piece in a steam box), it did make sense for like mine, he would dry it at 110° F for me for a short run of chairs. about six days. If he were to air-dry it, he would leave the piece in the form How to Dry it for two or three weeks. So I clamped So how did the material fare? I found my arm bows back into the form and that it worked as advertised. After let them sit. clamping up my arm bows, I let the wood air-dry in the form for a day, and How the Stuff is Made its moisture content dropped to about The way Compwood is made is just as 12 percent. Then I placed the for m in a interesting as using it. Compwood is box that was heated with a lightbulb to made by fi rst steaming the wood at 212° F 85° F and the work quickly dropped to 7 until it becomes plasticized. Then it is percent, according to our pinless mois- placed in a press that compresses the ture meter. That’s when I fi rst removed wood in length. A 3-meter-long piece it from the form. of wood will end up about 2.4 meters The piece sprang out a little at the long when in the press. When the press ends (though it was nothing unaccept- is released the board will expand again, The golden arches. I was well pleased with able). The reason for the springback but it will have lost about 5 percent of the way the Compwood behaved for these was that the wood likely wasn’t com- its length. arm bows. Now I just have to get on with pletely dry. This time in the press bends the saddling the seats of the chairs. My makeshift “kiln” wasn’t ideal. cells of the wood like an accordion. The Miller makes his kilns out of 2"-thick structural change in the cells is what pink foam insulation boards then heats allows the Compwood to bend when it tiple dimensions,” he says. “It’s when- the kiln with a ceramic heater with a is in a cold but wet state. ever the shape gets more sculptural that fan. His kilns are leaky, which is good Not all species work with this pro- this product becomes useful.” because it allows the moisture to escape. cess, but the range is expanding all the And while I can see that side of the He leaves parts in his kiln for about a time. Fluted Beams, which has the only equation, I also am a fan of it for my week. The results were impressive. Compwood press in the Americas, sells simple bend s because it’s easy to use in a “It was pretty much fl awless from a 14 different species, from beech, white small shop with limited equipment. Plus springback perspective,” Miller says. oak and walnut to cherry, elm and even it doesn’t fail spectacularly like some of “It didn’t move a bit.” osage orange. my steam-bending adventures. PWM Softwood species and exotics don’t seem to re spond well to t he Compwood Christopher is the editor of this magazine and process, though experiments with exot- secretly wishes at times to be a starving chairmaker, instead of a starving writer. ics are ongoing. As far as pricing goes, expect to spend $30 to $40 a linear foot for 8/4 material that is about 6" wide. Thin- u Go Online FOR MORE … ner stock is considerably less ($18.75 a linear foot). And Fluted Beams (fl uted For links to all these online extras, go to: beams.com or 253-988-2046) also offers u popularwoodworking.com/apr11 small bundles of Compwood for as little VIDEO: See Chris bend an arm bow as $20 that will allow you to experi- around a form using Compwood. ment with the wood without buying ARTICLE: Read about the drying process and see our makeshift kiln. large planks. WEB SITE: Visit the Fluted Beams web site Mroz quickly acknowledges that to order Compwood. because Compwood is expensive it’s WEB SITE: Read details of how Comp- not for every job. If the project can be wood is made at the factory. done with steam-bending, that defi- IN OUR STORE: ”Woodworker’s Guide to nitely is a cheaper way to go. Bending Wood.” Relax(ed).One of my arm bows sprung out a little after being released from the form before “I tend to focus on using t hi s product Our products are available online at: the arm bow was completely dry. Back onto for things that haven’t been done before u ShopWoodworking.com the form for you. – when the wood needs to bend in mul-

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