Wood Bending Tips; Making Wooden Cylindricals Wood Bending Making Wooden Cylindricals By far one of the most dramatic effects in the entire cosmos that will make you the envy of all your cohorts, neighbors, in-laws, main squeeze mama/poppa, or anyone else you want to impress the liederhosen off of, is when you employ the bent wood or radius effect in your projects. (You may even find them at your feet chanting, "we're not worthy!"....Who knows, after you master this section you might want to run for political office!!) But isn't wood bending an outrageously difficult process that takes a big shop and lot of expensive stuff?...you ask? My answer......yes and no. There are various methods of achieving the bent wood effect. As for solid wood bending, there are two time honored methods (and the only ones I know of). You could set up a chamber and steam or chemically treat the wood component until pliable enough to then bend it into your custom made jig or form until it has cooled and dried. Then hope that when you break your work out of the jig it will continue to hold the desired shape. Or...you could create a clamp jig or form, and slice your solid wood into thin strips of veneer and glue the strips together as you clamp them in the form until dry. OR...you can go back and review THE INsies AND OUTsies OF APPLYING WOOD VENEER, go out and purchase some "wiggle wood" at your local plywood source, take it back to your shop and crank out a lot of incredibly cool and curvy creations. WIGGLE WOOD?!!...Now I'm convinced that this guy has sawdust on the brain!!...you think to yourself? Not so...Oh skeptical future Congressperson!! "Wiggle wood" or what is more commonly called "bending stock " is the coolest stock material this wood miser has ever encountered in his long illustrious career. Standard run of the mill plywood consists of thinly sliced sheets of wood pressed and glued together arranged with the grain of each layer running perpendicular for strength and rigidity. http://members.aol.com/woodmiser1/bend.htm (1 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals But somewhere along the line some brilliant genius type asked the question, "what would happen if you ran the grain of all the layers in the same direction?"...And presto...wiggle wood was born!! Wiggle wood, (heretofore bending stock), is quite simply 3/8" luan species plywood with the grain running in the same direction throughout all of the layers which allows it to "wiggle" or freely bend. As a matter of fact it is somewhat hard to handle because it's like trying to manage a giant wet noodle! Bending stock sheets come in two configurations, 4ft x 8ft and 8ft x 4ft. One with the grain running the length, and one with the grain running the width. I first heard about this stuff from some guys in a top shop who used it for creating really cool and curvy geometric furniture and counter tops for office buildings. In their applications they would finish the products with a "Formica type" plastic laminate, but good old fashioned horse sense told this wood miser that it should work just as well with hardwood veneers. I think that it is safe to say that unless you happen to have an extremely enlightened and courageous retail venue in your area, you're going to have to once again employ the dumb phone call method of locating a source for bending stock. But even if it takes a while, don't give up. This stuff is widely used in custom cabinet shops in your area and they have to get it from somewhere. When you think about it, the possibilities of this stuff are endless! Anything from your basic modern cool cylinder shaped coffee table to a Frank Lloyd Wright type, art deco period two story dog house for Fido in the backyard (Turning Spot next door absolutely green with envy!) The trick is to create a skeletal framework or ribbing to wrap the bending stock around, and then apply your hardwood veneer over the bending stock... Obviously there is going to be a little more to it than just this, but have no fear misers and miserettes, we'll get more into the details as we move through this page. A basic geometric shape like a round end table is going to be pretty much a piece of cake. But if you are creating a piece of cabinetry or furniture needing doors with access to the interior the ribbing can get a little tricky. But for our purposes here, let's just keep it simple. For the results one can reap from this process the whole shebang takes surprisingly few tools. Your main squeeze power tool is going to be your jigsaw. Those web clamps mentioned in the "Clamp it Jed" index topic are a must here! You might want to keep most of your arsenal of clamps within easy reach. Also you will eventually need whatever tools you have acquired for applying wood veneer. Now...hold on to your socks misers and miserettes because the price of bending stock can be a bit unsettling when it first hits you. Last price I got on it per sheet was about $35 sawbucks and this was at a very reasonable supplier. I know that it sounds like a lot but when you factor in all of the things you can do with it (not to mention that a single 4 x 8 sheet just might be enough to cover a couple of medium http://members.aol.com/woodmiser1/bend.htm (2 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals to small projects), in my opinion, it's well worth it. Since the bending stock comes in 3/8" thickness it is a good idea (but not absolutely necessary if you want to save some sawbucks) to plan on two layers so you'll end up with the equivalent of 3/4" plywood for your carcass thickness. This will work to your advantage in several ways. You can "stagger" the butt seams of the bending stock layers or make sure they meet on opposite sides of the project which will help immensely to make them disappear when the veneer is applied. The two layers glued against each other will permanently arrest the tension created by pulling the bending stock skin over the ribbing. Once you have decided upon a shape for your creation, (in this case cylindrical) you need to plan your ribbing strategy. In our example we can get by with three plywood circular ribs. Some of the lesser expensive models of jigsaws can make it difficult to maintain a square and true edge on 3/4" plywood while scrolling or cutting circles (I'll have some tricks for you in the upcoming index topic "Cutting Square Circles"). But for the ribbing in this case, it isn't imperative that the edge be absolutely perfect. Although the more true it is the better glue bond you are going to get plus it helps in the end result to achieve a more perfect shape, but the bending stock skin will hide a multitude of sins. Intermediate 1 1/2" struts between the circular ribs will stabilize the ribbing and will also serve as backer field for your bending stock seams to give your fasteners and glue points a secure place to call home. This is extremely important because your bending stock will naturally want to pooch out at the seam and having a good solid wood substructure under the entire length of the seam will be invaluable for getting it under control. It's a good idea to use as few fasteners as possible in the bending stock skin because every one of them in the outer layer has to be countersunk, plugged and/or filled to perfection. If not they will show underneath the thin veneer. So the fewer fasteners we have to deal with the better. Besides, yellow carpenter glue is another one of those wonders of modern man. A moderate layer of glue between the rib edge and first layer of bending stock, (and consequently the same between the first and second layers), along with adequate clamping and dry time should do the job very nicely. Hopefully the only fastener points we'll have to deal with will be the seams, and the rib/strut joints. The real challenge is cutting your bending stock to size. As mentioned above the stuff is large and limp. Feeding it through a table saw could be like wrestling a giant flat python (although I have done it solo a few times). http://members.aol.com/woodmiser1/bend.htm (3 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals If you have a way to set up stiff catch tables on the in feed and out feed sides of your table saw, that'll do the job. More than likely though, your best bet will be to set a series of 8ft 2 x 4's on some saw horses for rigid support and either use your circular saw and sawboard, or just use your jigsaw (which is much more laborious but it'll get the job done!). Trying to measure the circumference of the ribbing to get the dead on accurate length of your skin presents another challenge. There are several ways to go about it. One (which I've never found to work) is to try to hold one end of your tape measure on a starting point and try to wrap it all the way around the rib,..(good luck on this one misers and miserettes!) Another is to reach way down into the depths of your subconscious memory, way back to middle school (or junior high) geometry class. Try and picture in your mind Mrs.Whatshername putting the formula for determining the circumference of a circle on the chalk board. If nothing comes to mind on this one you were probably snoozing, side faced in a puddle of drool on your desk. So for all of you, here is the formula. Got that?... What do you mean NO?.. now...pay attention! No...that's not the monogram on Gorbachev's PJ's. C'mon Find the distance of the radius of your rib (I'm assuming that you know what that is) and double it. Then multiply that figure times PI (3.14159265), and if you did it right, your answer should be the circumference. If you didn't, you're going to be in deep sheep dip, so you better double check your figures. Something you also have to keep in mind here is that the bending stock bends from the center of its core, which means that even if you measure and cut it exactly, the bending stock skin will come up short because the surface area facing the ribs will shrink during the bending process. Take heart fellow misers and miserettes, there is a much more "user friendly" method of getting the job done. Get a general idea of the circumference of your ribbing and over cut the length of the bending stock skin by a couple of inches. Then get out two of your old trusty web clamps and loop them a bit larger that it would take to get them around the ribbing and ratchet them a few times so they won't slip. Bend the first layer of your over-cut skin around the ribbing assembly and slip the web clamps over the whole affair, evenly space them, and ratchet them down. While tightening make sure that the skin is aligned good and straight and the ends overlap at the seam. http://members.aol.com/woodmiser1/bend.htm (4 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals Now put the old hairy eyeball on a side view of the overlap and make a pencil mark on the edge of the outer lap right above where the inner lap leading edge begins (make the mark just a little beyond {or longer} by an 1/8" or so). then carry the mark around to the face of the outer layer. Do the same thing from the other side view and then carefully take a straight edge and align it with the two marks carried over to the face and draw your line (make the line as best as you can with the clamps in place, then freshen it up after the clamps are off). Loosen the clamps, take the skin off and lay it out to make the cut. As I alluded to before, the butt seams of the bending stock skin have the potential of being a pain in the rumpus to deal with so we need to do everything possible up front to minimize the hassle down the road. If the two opposing edges of the seam are cut with a conventional 90° edge before the wrap, you will end up with a v-groove gap at the seam to deal with. That's why we need to slightly bevel the edges so that the points of the bevel will meet at the seam and will produce a good tight fit. We are going to repeat this process all over again for the second layer but we first have to make a permanent home for the first. Alignment is the key issue when preparing to wrap your first layer of bending stock. As an added measure of insurance you can take is to over cut the width of the bending stock skin a bit in case the alignment with the outer ribs isn't right on the money. The only drawback is that without the right tools, http://members.aol.com/woodmiser1/bend.htm (5 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals trimming the excess can be somewhat of a pain. Pains in the posterior notwithstanding, I personally like to take all of the margin of error measures I can get my hands on, even if it takes more time and work. On your first layer of skin locate a point dead center along the edge of what will eventually be the leading edge side of the but seam, about 3/8" from the edge. Drill and countersink a pilot hole for a screw at this point. Choose whichever support strut you're going to use as your starting platform and draw a line the length of it dead center widthwise. Take your time, use a sharp pencil and make it as accurate as possible. When you are working with cylindricals like this it's always a good idea to take the extra time to do dry runs to make absolutely sure that everything is copecetic before you commit yourself to glue up. Lie the skin face down and place the ribbing on top. then bend the starting edge of the ribbing up and align it with the center mark on the strut. Make sure that the outer edges are flush, or in the case of an over cut make sure that the overhang is equal in both sides. When all looks good, secure the starting edge by running a screw through the countersunk hole. Get your web clamps set up as before and within easy reach. Now slowly wrap the skin by rolling the rib work as if you were making a Paul Bunyan sized pig in a blanket. When you get it all the way around, grab the web clamps, slip them around and crank them down. This will give you a chance to check everything out and see if there are any modifications that have to be made before the glue up phase. At this point it's a good idea to mark the surface of the bending stock so you'll know where to set your fasteners and exactly where the ribbing is once everything has been covered up. Be especially sure to mark the location of the support strut that will be the starting point of the second layer of skin. If everything checks out to your satisfaction, gently undo the clamps, remove the screw, and lay the skin out again face down and get ready for the glue phase. Goosh some glue close to the edges and in the center where the ribs will make contact for about the first 6 inches or So. Then lay the rib work on the skin, align and fasten the starting edge as you did in the dry run. When the ribbing is aligned and attached to your satisfaction, go ahead and apply glue to the rest of the contact surfaces. No need to go ballistic here, a small bead applied from the bottle on the contact surfaces and a little smoothing with the finger should suffice. (Don't worry, yellow glue is not harmful to your skin, http://members.aol.com/woodmiser1/bend.htm (6 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals it peels right off after it dries. As a matter of fact it's a great way to freak out your unsuspecting buddies in that it looks just like you're peeling off a layer of skin!...very realistic..very cool!). A little glue will ooze out during the assembly and clamping but no worries mate, this is a good thing! It lets you know that the glue is making good contact. But all the same you'd better wipe off the excess before it dries. Before you go any further make sure your web clamps are set up as they were when you did the dry run and make sure they are untangled and close at hand. You don't want to find yourself in the precarious position of being in the middle of a critical glue up and finding out that your clamps are a couple of inches out of reach. Now slowly do the "Paul Bunyan sized pig in a blanket thing" again but remember, this time your committed! Yellow carpenter's glue will allow for a brief window of time in which you will get some slippy-slidey action and once you wrap the skin all the way around you can use this action to do your final alignment. Your window is only about five minutes (give or take) so don't monkey around here! As soon as you can get the web clamps around the work and ratchet them almost all the way down. Do whatever last minute adjustments that are needed and then go ahead and crank down them all the way. While your glue up dry time window is still open, go ahead and get your screws countersunk and set along both sides of the but seam. I would space them about 2½ inches apart. At this point if the seam still wants to pooch out, there's one more thing you can do before the window closes. Cut a 2 x 4 the same length as your but seam. Cover the seam with a buffer material such as aluminum foil or wax paper to prevent an unwanted glue bond. Now...go get two bar clamps or pipe clamps whichever is long enough to do the job. Center the flat side of the 2 x 4 over the seam, position your clamps on each end of the cylinder, and torque them both down just enough to flatten out the seam. Once you've got all of this under control, put the whole thing aside and take a break. As a matter of fact it might be a good idea to just leave it over night for good measure. The following morning after you wake up, do the java thing, do your routine ten mile jog, do your daily 20 minute aerobic workout, THEN hoof it on over to the shop and pull all of the clamps off and check out your work (Although you might want to change out of your speedo first). If everything looks cool, then you're ready to do the second layer of bending stock skin. Hopefully you took my advice and marked the location of the support strut that you're going to use as the next butt seam support. As you might have guessed the second layer process is amazingly similar to the first. The only notable difference is that the glue contact area is much broader this time. It's not really necessary to go bonkers and use up five bottles of yellow carpenter's glue to coat the http://members.aol.com/woodmiser1/bend.htm (7 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals entire contact surface area. It is important though to make sure that the edges and the but seam are coated in to get a sufficient "goosh" during clamping. As for the broader areas between the layers, just lay moderate beads of glue in bands about 3 or 4 inches apart around the first layer during the "Paul Bunyan Pig in a Blanket" process. Now just ditto what you did on the first layer. OK misers and miserettes, if you've gotten this far, you're just about ready to apply the hardwood veneer. If you haven't yet checked out "THE INsies AND OUTsies OF APPLYING WOOD VENEERS" index topic, you best go do that now......Done yet?.....OK, I'll wait.......(Sheesh!...not exactly a speed reader...huh?) One might think that applying wood veneers to a cylindrical shape would be much more challenging than a coventional flat planar surface.... "Not so,..misers and miserettes",...said the author happily!! The round shape of your work will actually make many aspects of veneering much easier. One critical challenge in applying veneers is keeping the surfaces separated once the glue is applied until you are ready to join them together. In the case of applying to a standard flat planar surface it's necessary to use slip sheets, props or some other kind of buffer system. The beauty of applying veneer to a curved surfaces such as cylinders and radii is that the glued surfaces are kept apart by pure and simple physics. As always, it is a grand idea to create margins of error for yourself whenever and wherever possible. I strongly suggest over cutting the width of the veneer by a least 1" which will allow for ½" overhang on both ends (if everything goes according to plan). Also the length of the venner, which corresponds with the circumference of the carcass, will need to be over cut by 1½" (but no more than 2½") to accommodate our magnificent dissappearing veneer butt seam magic trick! Now...it's important to get a starting line for your veneer application established on the carcass body which presents another interesting challenge. Normally one could just lay a framing square along the edge of a flat plane and make the mark and be done with it...It's not quite that simple in the case of a curved surface. In case you haven't figured it out by now, I'm a BIG believer in dry runs, even if it draggs out the production time...(better safe than sorry!). In this case we can use the dry run to kill several birds with one stone. Once you have the veneer cut to application size and before you have applied any contact cement, take a moment to wrap the veneer around the carcass as tight as you can get it and still be able to get http://members.aol.com/woodmiser1/bend.htm (8 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals some slippage for adjustment. If need be, adjust the venner so that all of the margins and overlaps are even and straight or in other words, positioned just the way you would like for it to end up after the glue up appilcation. Also make sure that the veneer butt seam will not break over the bending stock butt seam. If all looks good, now's your golden opportunity to make all of your guide marks and lines that should guarantee you an uneventful and text book final application of your veneer. Lay the carcass on its side with the seam horizonal and facing up and hold it against your belly ("tummy" for you miserettes) to help keep the veneer from slipping. Lift the outer flap of the overlaping veneer enough to get your fingers in to hold the inner flap or beginning edge of the veneer. If you have gotten this far without the veneer slipping, all you have to do is to mark your beginning line on the carcass using the edge of the veneer as your straight edge. You also might want to take this opportunity to mark the veneer where it hits the carcass to help assure the correct overhang. Now fellow misers and miserettes, you're almost ready to start down the home stretch. We're at the point now where it's time to apply the contact cement to both the carcass and the back side of the veneer but before we go any further there's one little important detour we need to take in preparation for the "magnificent veneer butt seam dissappearing magic trick" After you have sufficiently coated the carcass body with contact cement and are ready to tackle the back side of the veneer, plug this extra little procedure into your process. When you coat the veneer with contact cement hold back from the seam edge a good 2" on each end...that's right..leave them glueless. As a matter of fact you might want to draw a straight line 2" from each end and glue right up to the lines but no further. Don't worry misers and miserettes, there is a method to my maddness! After you have coated in the veneer, let it dry, and then you're ready for the application. I want to reemphasize the importance of taking extra measures to make sure that your veneer butt seam ends up no where near the bending stock butt seam on the carcass body. Make sure that your work surface is as clean and dust free as possible. Now lay your glue coated carcass on its side with the pencil line facing up. Don't worry about the glued up carcass making contact with the work surface. If the surface is clean and dust free and has no contact cement residue on it, the most that will happen is that the carcass will make popping and cracking noises as you move it around. With the carcass held steady against your belly (tummy, stomach WHATEVER!), carefully pull the face down veneer over the carcass to the starter pencil line and get it properly aligned. Make sure that it is right on the pencil line and the overhang margins are where they're supposed to be. Making sure that the veneer dosen't slip out of alignment, and with the trailing edge of the veneer still somewhat flat on the work surface, smooth the veneer with your fingers just far enough down the carcass so that the leading edge of the glued veener underside makes contact with the carcass. The point http://members.aol.com/woodmiser1/bend.htm (9 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals of all this is to tack the veneer to the carcass enough so a good alignment is assured as we move the whole shebang around a little. Now misers and miserettes, this part gets a little tricky. We're going to have to flip the whole affair over so the glue side of the veneer is facing up and do it without the two glued surfaces accidently making contact where we don't want them to. Actually It's not as difficult as it might sound. If you want you can use some sort of slip sheet as a little added insurance, but more than likely if you're careful you can get it done with no problems. From here on out it's a piece of cake folks! Putting as much pressure as possible on the carcass, just slowly roll it forward until the veneer has made full contact all the way around the carcass and the veneer ends have overlapped. Smooth out any visible air pockets with your fingers. The secret to a good contact bond is to apply as much pressure as you can muster. Once again a curved surface presents some interesting challenges when it come time to roll out the venner. Using the standard hard rubber rolling device can be a little frustrating. A great way to get the job done is to lay out a clean drop cloth (or better yet a rubber mat) on a flat floor surface. This way you can use your whole body weight to roll it against the floor. You could even sit on it and rock back and forth, shifting it now and then until the whole thing is done. A word of caution though. The "sit and shift" method can look very wierd to an on looking stranger. It might be a good idea to shut the curtains and pull the blinds before you do this one. You never know what the neighborhood gossip hotline might do with this one! After you've got the veneer rolled out to your satisfaction, go ahead and carefully trim off the overhang with your utility knife (make sure the blade is new and sharp). Hold the overhanging veneer with one hand gently pulling it away from the carcass as you cut with a sawing motion using the carcass body edge as a guide. Now is the moment you all have been patiently wainting for...The world famous A Wood Miser's Workshop magnificent veneer butt seam dissappearing magic trick (It might take you longer to say it than to actually do it!). Lay the carcass on its side again with the overlapping veneer seam up. Once again, put the 'ole hairy eyeball on the edge where the ends overlap. You want to put a mark on the veneer face dead center in the middle of the field between the beginning edge and the trailing edge of the veneer (you can guesstimate where center is, accuracy is not absolutely imperative here). Do the same on the opposite end of the overlap. For this part you're going to need a substancial and reliable metal straight edge for a cutting guide. First take your straight edge and draw your cut line connecting the two marks you just made on the veneer face. Now...holding the straight edge absolutely still on your cut line with your hand while you http://members.aol.com/woodmiser1/bend.htm (10 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals make this critical cut is massively difficult and risky to say the least. Using a couple of bar clamps or pipe clamps to hold the straight edge in place would be the best bet. The object here is to make a cut right on your line that will penetrate both layers of the overlapping veneer keeping the utility knife as perfectly perpendicular to the surface as possible. Once you've made the cut, the waste of the outer layer of the veener will fall away. Now unclamp your straight edge because we're going to have to go in and get the waste of the inner layer. It is for this very reason misers and miserettes, that we left the edges "glueless" in the first place. Gently lift the edge of the veneer that is covering the inner waste piece until you can get a hold of the http://members.aol.com/woodmiser1/bend.htm (11 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals rascal. It might act like it dosen't want to come out of there but just patiently work it around or rock it until it gives up the ghost. The only thing left to do now is to coat in the small areas of the veneer that you left glueless. This can be accomplished by gently lifting each flap and coating the underside with a small brush. You're going to need to get the contact cement as deep into the area already making contact as possible, but be careful to not cause a glue build up under there that could end up leaving a nasty looking lump under the veneer that you may not be able to smooth out. Just like all the other contact applications, the glue coated flaps have to dry enough to become tacky before you lay them down, and in the mean time you have to keep them from making contact. Having a couple of small precut blocks to prop between the flap ends will hold them suspended until dry enough to lay them down. http://members.aol.com/woodmiser1/bend.htm (12 of 13)8/12/2004 3:28:22 PM Wood Bending Tips; Making Wooden Cylindricals Now, misers and miserettes...after the flaps have dried to your satisfaction, the time has arrived for the A Wood Miser's Workshop magnificent veneer butt seam dissappearing magic trick..finale! Just remove the prop blocks and smooth the flaps into contact with the carcass, and presto chango, the edges meet tight and straight, virtually dissappearing! Close the curtains one more time, put the project seam down on your clean floor surface and do the sit and shift thing again to secure the veneer seam. Now...a very slight touch up on the seam here and there with a little wood filler (if you so desire), a little blending with some sand paper, then a graceful twirl and a deep bow before the audience as the ooh's and ah's crescendo to a deafening level! Last but not least...as the pretty lady in the metalic red, sequenced evening gown hands you the bouquet of roses, try to keep a humble look on your face as you blow kisses at the adoring crowd. Now might be a good time, misers and miserettes, to start planning your campaign strategy for the next Congressional race. But before you get all wrapped up in that, let's head back to the index and see what else we can add to our war chest! [Back to the Wood Miser's Index of Topics] http://members.aol.com/woodmiser1/bend.htm (13 of 13)8/12/2004 3:28:22 PM