Making the body
Making a solid body
Preparing the body blank
For making the body of an electric guitar from one piece of wood
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a thickness planer or a drum sander are the obvious tools to use. Planers intended for professional use are wide enough and therefore suitable for this purpose, while common “hobby” thickness planers that can accomodate a maximum stock width of 260mm or 300mm (10" or 12") cannot be used for planing one-piece guitar bodies. Getting hold of high-quality and sufficiently wide pieces of wood is another potential problem. In most cases the body will therefore have to be made by gluing two halves together.
If you buy finished, ready-cut wood from a tonewood supplier you can obviously skip the steps of work described on the
2following pages. For some of these steps of work you would need quite expensive machines anyway. If, however, you have decided to do it all yourself and you have seasoned but otherwise untreated wood in front of you (as in picture 1, which shows a parcel I got from the Austrian tonewood supplier Kölbl), you will have to cut and plane the wood to the required dimensions yourself. Two pieces can obviously also be cut from one long plank. The plank shown in pictures 2 to 5 is about 60mm (23/8") thick and one meter (about 1 yard) long.
Start by planing one of the surfaces flat (2). Move the plank over the jointer, using a push stick for pushing it. The shape of
3the push stick does not really matter; it can be rounded off and given a more hand-friendly shape than the one in the picture. When planing hardwood not more than 3mm (1/8") should be planed off in one pass and several passes may be required until the surface is flat. If the plank is too wide for the jointer, reduce its width with a tablesaw (see below).
Cut a straight edge on the tablesaw (3). Since in this state the plank cannot be guided along the rip fence of the tablesaw, I placed it on a rectangular jig. The guard was removed only for taking the picture.
Now plane the newly-sawn edge flat and square to the main surface (4). Before you start make sure that the fence is set
4exactly at right angles to the jointer table (correct it if necessary). These two surfaces have to be exactly square to each other before work on the two other surfaces is started.
Then saw the piece of wood to its final width of about 200mm (77/8"), as shown in picture 5, where the slanting outside edge of the plank makes the piece look wider than it actually is. This sawn edge remains rough and will later be used for positioning the clamps when gluing the body together.
Finally plane the wood down to a thickness of (usually) 45mm (13/4") (6). Again the amount taken off in one pass should not exceed 3mm (1/8"). Thickness planers tend to plane off slightly more over the last few inches of a board or plank because the piece of wood loses touch with the guide rollers as it comes out of the planer, which in turn causes the rear end of the wood to be lifted slightly. If you have several pieces to plane, you can limit this problem to the last piece by feeding the individual pieces into the machine one after the other. Machine-planed pieces of wood should therefore always be left 50mm (2") longer so that areas with planing defects can be sawn off later. If you have one long piece of wood, cut it through in the middle (7). The two halves can then be jointed and glued together.
Before gluing two pieces together hold them against each other and up to the light to find out if there are any gaps. If there are large gaps, the surfaces to be joined have to be planed until they are flat and hardly any or no light at all shines through. When planing make sure that the jointer knives are sharp as only sharp knives will give good results. Fasten the fence at right angles to the jointer table. Set the guard so that the unused part of the rotating knives is hidden, and set the depth of cut to no more than 0.4mm (1/64"). Then slowly push the first body half (bottom side facing the fence) over the jointer (8). Make sure it is in permanent contact with the fence and press the board down at the outfeed table only. If the edge of the board has a convex curve, start planing just before the middle on the first pass and only plane down the whole length of the board on the second pass. Repeat this procedure until the edge is perfectly straight. Now move the second body half, with its upper side facing the fence, over the jointer. Planing one board with its upper side and the other with its bottom side facing the fence has the advantage of still giving matching edges even if the fence should not have been set exactly at right angles to the table.
When there are no gaps along the edges of the two pieces they are ready for gluing. Take your time; it is possible to join two pieces so that the glue line is almost invisible.
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Body blank half between two boards
With appropriate jigs routers can also be used for jointing or planing. The following examples will illustrate how versatile routers are and how they can make buying a jointer or thickness planer unnecessary. Quite commonly the width of work that can be accomodated by most thickness planers used by hobby woodworkers is below what is required for preparing guitar bodies anyway.
Jointing with a router (1)
When I started building guitars I used a router for jointing the body halves as I did not own a jointer then. The method I used works quite well with thicker body pieces and consists of a jig with which a router is guided over the edges to be jointed. The body halves have to be accurately thickness-planed or thickness-sanded.
Put a thin, narrow piece of wood on a flat surface and place one body half on it so that the edge that you are going to work on faces downwards. Then put a thin board (plywood or hardboard) and one board with a perfectly straight edge (I used two 19mm (3/4")-thick plywood boards) to the left and right of it, clamp it all together with two clamps and mount it in the workbench upside down, with the edge that is to be worked facing upwards.
Then take a square and check whether the edges of the two outer boards, which will later serve as a table for the router, are the same height. If they aren't, repeat the
procedure described above. The thin boards serve to keep the distance between the router bit and the boards on the sides. Now the router can be placed on the edges of the two outer boards. Mount a cutter as great in diameter as possible (a special surface-trim cutter is highly recommended). Lower the cutter onto the wood surface and move it over the whole of the side. The result of this should be a flat area, which after careful (optional) treatment with a scraper is ready for gluing. Proceed similarly with the side of the second piece of wood that is to be glued to the first one.
For jointing thin boards, such as those used for a body top, and if the length of the cutter permits, both boards can be fastened together in a flat, lying position and then be routed together (bookmatching). The router is then guided along a fence which is mounted exactly parallel to the edge of the boards. This is, however, only possible if the boards have been accurately thick- ness-planed or sanded and if the router is pressed firmly on it to prevent it from tilting and doing damage to the wood surface. Try to rout off rather little at the beginning and keep moving the fence by a very small amount at a time until wood is routed off over the whole length of the boards. Because it leaves a very smooth surface a spiral-fluted cutter bit is the best choice for this task.
Thickness-planing jig (2)
The jig consists of a plywood board with two walls on either side and one rail. On this rail the router can be moved across the board, while movements along the board are possible by pushing the rail on the walls. A well-working jig should allow for the router to be guided over the whole surface. I used 19mm (3/4")-thick plywood for building it. Since the individual pieces needed should be available at most larger DIY stores, most of which even offer the service of
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Rail
Body blank to be planed
Wall
Plywood board
cutting the wood to the required dimensions, getting hold of the material needed should not really be a problem.
Fasten the board that will be planed with wedges to keep it from moving from one side to the other. If it has warps, insert wedges under it as well. Mount the largest cutter bit that you have on the router - the greater its diameter is, the faster you will be and the nicer the surface will look. If you have a bit of money to spare, you can also buy special surface-trim cutters; but note that there is a limit to the maximum cutter diameter a router can hold. Place the router on the jig and lower it not more than 2mm (3/ 32") into the wood. Then start routing, always moving in one straight line from the beginning to the end. Proceed like this until, line by line, the whole surface has been routed.
As a smooth, pretty surface will only be obtained if the bit can reach the entire surface, it is important that the jig is not made too small. Also take into account (a) the space that will be taken by the router on both ends of the rail, and
(b) the space needed by the rail itself as it is moved to the ends. The rail has to be sufficiently stiffened to keep it from bending under the weight of the router. After one side of the board has been routed turn it over, fasten it again with wedges and rout the other side until it is flat, too.
Gluing up the body blank
For gluing the two halves of the body together any ordinary commercial wood glue will do - it doesn't have to be water resistant. White PVA (polyvinyl acetate) glue is easiest to obtain. Only buy it in quantities that you can use up within a year or so as its shelf life is limited. Basically two types of glue can be distinguished: those that take longer to set (advantage: you have more time for placing the clamps), and others that set quickly. The common PVA glue must be clamped as soon as possible or at least within 5 minutes after applying the glue. Always read the manufacturer's instructions that come with the product.
Glued joints will only be strong and durable if the glue is applied in a thin layer; thick layers of glue will break. The quality of a glued joint depends on how clean and smooth the two surfaces onto which the glue is applied are. A well-made glued joint will never break at the joint, just as a welded joint will never break at the point where the two pieces are welded together. Dowels are not required. The best and smoothest surfaces for gluing will be achieved by professional manual planing.
Pieces of wood can only be glued together along the direction of their grain; glued joints of end-grain surfaces will not be strong. Pieces that are to be glued together should only be planed immediately before gluing as this will give clean and smooth surfaces.
Before applying any glue cover the table or workbench with some pages from a newspaper. Also have all clamps that are needed ready. It might also be a good idea to dry-clamp the pieces together without glue and to check whether the individual pieces are in contact in all places or whether there are any unforeseen problems arising from tightening the clamps. If everything is fine, untighten the clamps, apply glue to both surfaces and spread it thinly and evenly with your little finger. Use the little finger instead of your index finger so that you can grab something in between without messing it up with glue. If you apply too much glue and/or spread it unevenly, much more pressure will be needed to press the two pieces together. In theory, two perfectly flat surfaces would require no pressure whatsorever as the pressure is only needed to maintain contact between the two pieces until the glue sets and takes over this “job”. In practice, however, clamps are always required. Keep in mind that they exert a local pressure, as when pressing down a sponge with your index finger. To spread the pressure evenly over a larger area a strong piece of wood should always be placed between the clamps and the pieces that are glued together. Applying too much pressure should be avoided as this can lead to most of the glue being squeezed out.
Hide glue
Hide glue is made from animal hides and consists of small flakes which are soaked in cold water for an hour and then heated and applied with a brush. Always mix glue and water by weight and not by volume. Mix about one part of hide glue with two parts of water. The consistency of hide glue can always be adjusted by adding water. Do not prepare too much of it at a time and keep it in the fridge. Don't worry - hide glue is absolutely nontoxic. It gives a very strong joint and sets very quickly, but you should leave it to dry and not do any further work on the glued-together parts for the next 24 hours. Hide glue joints have been around for centuries and some of the joints made with this type of glue are still as strong as ever.
Hide glue must never be brought to the boil. For this reason it is advisable to heat the mixture in a water-bath or in a baby-bottle warmer to a maximum temperature of 65°C (150°F).
Parts are best glued up at normal room temperature; if it is too cold, hide glue will immediately start to gel. By using a hair drier or a mode- rately-set heat gun you can keep the glue and the parts hot enough until clamping pressure is applied.
One great advantage of using hide glue is that joints made with this type of glue can easily be disassembled again by reheating. If an undone joint is to be reglued, the remaining pieces of glue don't have to be removed as the newlyapplied hot glue will combine with it. And, finally, hide glue is not as slippery as for instance PVA glue so that fewer additional clamps are needed to keep the pieces in place.
Panel clamps
My personal favorite is a special panel clamp (1). If you manage to find one of these traditional, Euro- pean-style clamps in a shop, don't hesitate to buy it. The set I have consists of a cast-iron cross with four 18mm-diameter tenons and another cross with an additional worm-gear spindle. Depending on which side the asymmetric cross is stuck in, it allows gluing together either 20mm (3/4") or 40mm-50mm (15/8"-2")-thick pieces of wood. Additionally, you might want to buy a special wrench. And last but not least each clamp needs two hardwood boards with several holes drilled into them (1). This type of clamp has been around for about a century in German woodshops but was “re-invented” in the “New World” and patented by Lee Valley & Veritas.The Veritas Panel Clamp can be found in their catalog.There are also a few other similar working clamps around; some of these can be found for instance in Woodcraft's catalog.
The panel clamp is set to the required width by positioning the crosses. Then place the two body halves between the clamps (3), putting a bit of newsprint in between to soak up any excess glue that might be squeezed out. Next put on the top boards (4) and tighten the clamps.
This type of clamp has the huge advantage of ensuring that the pieces that are glued together remain absolutely flush. The more you tighten the clamp, the greater the tension on the top and bottom board will become, thus ensuring that the two parts of the body are absolutely flush with each other. If you want, place a third panel clamp or an ordinary clamp in the middle (5). If the panel clamp boards are thick enough to allow putting in the crosses from both sides, several bodies can be glued together at once, which is not only faster but also requires less space. Only one board is needed for each additional body.
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Bar clamps (2) and pipe clamps
Apart from the well-known common clamps there are also bar clamps or pipe clamps which are infinitely variable in length.With a
Cramping Head Set from the British company Record you can make your own bar clamps from 25mm (1")- thick square timber (2).
For making pipe clamps you can buy a special set which fits on a 3/4" standard pipe threaded at one end.