Most guitars feature binding and decorative purfling around the top and bottom edges of the body of the instrument. This page contains step-by-step instructions for installing the bindings and purflings. Some instruments have bound fretboards and headstocks as well. Although there are not instructions for those operations on this page, it is a fairly straight forward matter to apply the techniques here to binding those areas as well. This page primarily discusses the application of wood bindings to classical guitars. In general, wood bindings are more difficult to apply than plastic, and binding the classical guitar is more difficult than binding the steel string acoustic. This by way of saying that, once you understand how this operation is performed with wood bindings on the classical guitar, it is relatively simple to transfer that knowledge to the use of plastic binding material and/or to the binding of the steel string.
Initially appeared: October 31, 2014
Last updated: September 11, 2018
Bindings serve two functions. The first is to protect the edges of the instrument from damage caused by knocks. The second is to seal up the end grain of the plates, which helps prevent fast absorption and loss of moisture, which helps prevent or at least slow dimensional changes due to changes in temperature and humidity. Given the first function, the material chosen for bindings is usually something that is hard and durable. Various plastics are used for bindings, but the traditional material is wood, and this page will outline the installation of wood bindings. In general, a wood species that is at least as hard and impact resistant as that of the ribs is used, but this is not a hard and fast rule. Bindings also serve a decorative function, and binding material is often selected simply for looks.
Wood bindings are generally made of strips of wood of about the same thickness as the ribs of the instrument and about as tall as the thickness of the plates or even taller. These strips are available from lutherie suppliers, but you can make them yourself by ripping long strips of any suitable wood. Often your side blanks will be wide enough so you can rip some binding strips from them after the sides have been thicknessed. Commercially made strips are usually about 0.25" tall. For most guitars, two lengths of binding are used for each plate, which means there will be a joint at the tail end of the instrument, at or near the centerline of the plate. Strips of about 32" can be used for most guitars. If you are cutting your own strips and are working on an exceptionally large or exceptionally small instrument, it is a good idea to measure the distance around the edge of the body to determine how long the binding strips should be.
Bindings are inlaid into channels cut into the edges of the instrument body where the plates meet the ribs. They are often decorated with additional wood strips called purflings. The purfling strips between the bindings and the ribs are generally referred to as side purflings, and the ones between binding and plate are called either plate purflings or more commonly just purflings. Purfling strips are also available from lutherie suppliers. They are ripped from sheets of veneer. These can also be shop made with a veneer saw and a straight fence to run the saw against. Commercial purfling strips come in two widths. The wide strips are approximately as wide as the bindings are tall (about 0.25"). The narrow strips are considerably thinner (about 0.1"), which is about the thickness of the binding material.
Although it may be possible to concoct a binding and purfling scheme which simply stacks narrow purfling strips under the binding and wide purfling strips next to the binding, such a scheme can only work if the combined height of the binding and side purfling strips is less than the height of the interior linings plus the thickness of the plate (figures A-C above). If it were equal or greater, cutting the channel for the bindings and purflings would also cut the plate right off the body. In practice this is rarely an issue because "standard" interior lining strips are usually tall enough for most binding and side purfling schemes. The combined thickness of the binding and (full height) plate purflings cannot exceed the thickness of the ribs and that of the linings either. When wider top purflings are desired, a separate, shallower, channel is cut just for the purflings, and narrower purflings are used. In this case the purfling channel is always less than the thickness of the plate and so in theory any purfling width can be used (figures D and E above). But in practice most folks make sure the purfling channel is no wider than the linings.
In general you can make up any kind of binding/purfling scheme you like, based totally on aesthetics. But if you will be cutting your binding and purfling channels using a router and pattern/rabbeting bit, you'll need to be sure the depths of the bindings and purflings will fit into channels that can be cut with the guide bearings supplied with (or available for) your pattern/rabbeting bit. There are special purpose guide bearing sets available from lutherie suppliers with fine gradations in size, but these sets are quite expensive. Because these are special-purpose tools, I generally recommend that beginners chose simple schemes that can be implemented using off-the-shelf rabbeting bits and bearings.
As mentioned, you can buy precut binding and purfling strips that are sized so they can be used together. If you make your own, be sure the veneer strips you use for the side purflings are the same width as the thickness of the strips you use for the bindings. The veneer strips for the top purflings should be a lot thinner, such that the channel they sit in is not as deep as the plates are thick. See the figures above. The first thing to do is to collect and lay out all the strips you will need for the binding job.
It is good to have some extras, because breakage is always a possibility. The first thing to do it to dry fit one of the binding strips with the side purflings. On this page I am using a simple scheme that uses just a single side purfling strip. Since I have purchased the materials from the same supplier the dimensions are perfect. But it is not the end of the world if the side purfling strip(s) is a little wider or narrower than the binding strip is thick. You will have to keep this in mind as you glue the side purflings to the bindings however, and compensate accordingly. If the side purfling strips are a bit wide they will be scraped to the proper width after the binding strips are glued up. If they are a bit narrow, then the short side will be used as the inside when they are glued into the body, so this will be invisible.
Basically what you want to do here is to glue the side purfling strip(s) to the binding strip while both are straight. The process is straight forward - just apply glue and clamp.
Note that you'll need a heap of little clamps to do this. I use about 48 for each strip. You can use spring clothespins if you like, but if you use wooden ones it is a good idea to wax the jaws a bit so glue doesn't stick to them. Here is another view of the clamping.
The process is simple enough. Apply glue to a section of purfling strips, stick them together and to the binding strip, wipe and squeeze the whole thing together with a rag, then apply clamps. Repeat this in sections for the rest of the length of the strips. If you are using a yellow glue with an extended open time you can usually do the whole thing at one go. As you glue and clamp you want to be sure that one side of the glued up stack has all the pieces flush. With a single side purfling strip that is exactly the correct width, this is simple to do.
But things get tricky if you are using fast setting glue like hot hide glue and/or you are trying to glue up a lot of purfling strips and/or the widths of those strips are not exactly correct. For such cases you can buy a little purfling gluing fixture which is a plastic block with an adjustable width slot in it. You set the slot width to the height of your binding stack, apply glue to a section of purfling strips and put the stack together as above, then slide the whole thing into the plastic slot, keeping the pieces in contact with the bottom of the slot. As the stack exits the slot, you apply clamps. The process is continued for the entire length of the strip.
Leave the stack(s) to dry overnight, then remove the clamps. Now the entire stack is scraped with a card scraper on both sides to remove surface glue and to true up the sides.
You can also do this by running the strips through a thickness sander. After the sides and bottoms of the stacks have been scraped, scrap a chamfer on one of the side purfling edges for the entire length of the strip. This is an important step because the channel you will eventually cut into the body edge to accept the bindings will never have a perfectly sharp inside corner. Therefor, if you don't chamfer this edge it will be difficult to get the bindings to fit tightly into the channel.
The strips will be bent over an iron just like the sides are bent. Because they are so delicate it is a lot easier to bend them if all the strips are ganged together and bent at the same time. Quicker, too. All four strips can be bent for non-cutaway instruments at the same time. If the instrument has a cutaway, the two on the cutaway side are bent together and the two on the non-cutaway side are bent together. Note that in either case the two strips that will go on one side of the instrument are oriented so the purfling strips are touching. Also be sure that all the chamfered edges end up on the same side of the gang of strips!
The strips are just taped together at regular intervals with paper tape. Put the tape only on what will be the outside surfaces of the strips, that is, the side that doesn't have the chamfer. This is done so we don't run the tape over the hot iron, which will soften the tape adhesive and maybe stain the binding in the process.
The next step is to mark the location where the waist bend will go on the strips. Measure around the body from the centerline at the tail end to the nadir of the waist, using a flexible taylor's tape measure. Write down the length. Then measure from the centerline of the body at the neck end to the nadir of the waist, too, and write that down. The two numbers should add up to less than the length of your binding strips. Half the difference and add it to the tail end to waist measurement. Measure from one end of the taped binding strips and make a pencil mark right across all strips. This will be where the waist bend will go. You may need to move one or more pieces of tape if they are too near this mark. You'll want to place tape strips about three inches from either side of this mark. This is done because the waist bend will be done on the marked side of the bundle, and again we don't want to run tape across the iron.
Once the bundle is marked and taped it is ready to be bent.
The bundle of binding pieces is bent on a hot iron in the same manner as the ribs of the instrument were bent. If you haven't already done so, see Building the Rib Assembly on this site for more information about that. As when bending the ribs, I start with the waist bend first. Spray the bundle with some water from a spray bottle, and then gently bend at the waist mark.
Be very gentle with your bends. If you break the binding you may be able to repair the break with cyanoacrylate glue and then continue, but sometimes the only thing to do is to start over again from scratch. You can check your bends for fit on the instrument body itself or in the mold.
In either case, after you've got the waist bent accurately you can proceed on to the upper and lower bouts. Check your progress as you go. The fit need not be as critical as it was for the ribs, at least not for the upper and lower bout areas. But for the waist the fit has to be very good in order to get the bindings to fit right. Once you've got the stack bent to a good fit, you can either clamp it inside the mold used to bend the ribs or you can simply attach it to the outside of the body. In this photo I have the bundle of bent bindings secured to the instrument body using surgical tubing. Let the bindings cool and dry overnight.
Now remove the bundle from whatever you used to mold it to shape and then remove the tape. Check the side purfling strips carefully to see if any of them got creased or came unglued in any places. In these cases you can usually just spot glue and clamp the lose purfling back to the binding. If you need to do this be sure to scrape the binding clean after the glue is dry. If you end up with a broken purfling strip that is not amenable to spot repair it may be necessary to build another strip from scratch.
The next step in the process is to cut the channels around the edges of the body that the bindings and purflings will fit into. There are basically two methods for doing this. The first is to use a special purpose cutter called a gramil or a purfling cutter to mark the edges of the cuts to be made in the plate and ribs, and then to chisel away the waste between those cuts using a chisel. The second method is to use a router and pattern bit to do the same thing. In cases where the plates are highly domed, some sort of special jig to hold the router is also necessary to maintain straight binding channels. I am going to describe both methods in some detail. I'll also say that my own method is a hybrid - I use the gramil to outline the cuts and the router to remove the waste. This method gives the cleanest cut on the plates, which makes for good fitting bindings.
Because both methods route channels using tools that index off the surface of the ribs, you'll want to be sure that the ribs have been sanded smooth to about 100 CAMI grit to remove any remaining flats and dips in the surface.
But before approaching the actual instrument body it is a very good idea to make trial cuts in a block of scrap. This gauge block is used to dial in the dimensions of the cuts for either gramil/chisel or router methods. Once you've made channels in the gauge block and successfully checked the fit of the binding strip, then you can go on to the actual guitar body. The gauge block also provides an easy way to reset the gramil for plate and side cuts.
To use the gramil, first adjust it to make a marking cut of the thickness of the binding in the gauge block. The cutting height is adjusted for a shallow cut - too deep, and you risk splitting the wood when the cutting blade is aligned with the grain. The depth of cut is set to the thickness of the binding. It is easiest to do this by holding the binding strip right on the fence of the gramil while adjusting the depth. Once set, use the gramil to mark all the way across one of the top edges of the gauge block.
That cut is the equivalent of cutting into the surface of one of the plates of the instrument. Next, the gramil depth is reset to the height of the binding. Then the gramil is used to mark all the way across the top edge of the gauge block, like this.
This is the equivalent of cutting into the ribs of the instrument. With both cuts made, the gauge block looks like this.
Now the waste between the cuts is removed with a chisel. It is easiest to do this by removing waste down to the depth of the gramil cut, then resetting the cutting height on the gramil a bit deeper, re-cutting with the gramil, then repeating the chiseling. In this way you get nice sharp walls of the resulting channel. When you are done, use a small rectangular file with one safe edge to clean up the channel. Then check the channel for fit with the binding. It it ends up too deep in either direction you'll have to try again, using a different edge of the gauge block. Once you get it right though, the gauge block can be used in setting the gramil for cuts in the instrument body.
Set the gramil using the gauge block and set its blade depth for a marking cut. Keeping the fence of the gramil always in contact with the rib surface, mark around both top and bottom plates. If you are building an instrument that does not have its neck attached at this point, you'll be able to go all the way around each plate. But if you are building an instrument that makes use of typical Spanish guitar construction you will only be able to get close to the neck. Get as close as you can.
Now set the gramil using the gauge block to mark the cut for the bottom of the binding channel, cutting the ribs. Again, this is just a marking cut.
Now, just as was done for the gauge block, chisel out the waste between the marked cuts. You can make good use of the gramil in this process. First chisel out waste to the depth of the mark in the plates, then do the same to the depth of the mark on the ribs. Increase the blade exposure of the gramil and mark surfaces again, this time going a bit deeper, then chisel away more waste. Continue marking and chiseling until the channel is done. One warning though. You will not be able to use the gramil to cut deeply into the plates at the waste. This is because the gramil blade has some width, and the outside edges of the blade would end up outside of the cut. The end result is the cut would be widened here, which is not what you want. So the waste area in the plates around the waste bend will have to be done by hand, using chisel and gouge.
Once the bearing is selected and the bit height is set, it is a simple matter to route a channel in one edge of the gauge block.
As you can see in the following photo which shows the channel partially routed, I actually mark the channel edges using the gramil even when I use the router. I find it leaves cleaner edges in the plates of the instrument.
When you have routed the binding channel in the gauge block, test the fit using one of the binding strips. If the fit is not right, reset the router depth or replace the guide bearing as necessary and then try again on another edge of the gauge block. Once you've got a good fit, you are ready to route the binding channels in the instrument. The gauge block can also be used if you need to set up the router again for this cut.
Now you can turn your attention to routing the binding channels in the instrument. If the instrument has flat plates or plates that are domed to a radius of 15' or greater and if it doesn't have pointy cutaways you can just sit the router right on the plates and route away. But if the plates are more highly domed or otherwise arched or if the body has a cutaway that you can't securely rest a trim router on then you will have to make use of a special routing jig for doing this operation. Use of such jigs is discussed below. But here I'll discuss the case where the plates are flat or nearly so, and also provide some general tips for routing.
If the instrument's neck is not yet attached you'll be able to route all the way around the body, which is convenient. There is one thing to look out for though before you start. If the body has a mortise of any kind for attaching the neck, make sure that the router bearing cannot drop into this mortise when you are routing the back. If it does you'll take a chunk out of the back that will be difficult to repair. If there is a mortise and it is long enough so that this will be a problem there are two things you can do. The first is to wedge a small piece of scrap into the mortise and then trim it flush, so that the bearing will simply ride over it. The other thing you can do is to simply not route over the mortise, leaving a small section of channel that will need to be chiseled out by hand.
But if the neck is attached you'll only be able to route close to the neck, so you'll have to finish the channel using knife and chisel. If the neck is attached the first thing you must do before making the cut is to secure a stop for the router to prevent it from running into the neck and routing a chunk out of it. Just locate a clamp on the plate so it is positioned to prevent the router from getting too close to the neck.
Once the stop is in place you can route the channel. Do the routing in multiple passes so you don't risk tearing out any large chunks of wood. You'll need to make both conventional and climb cuts to avoid tearing out wood from the plates. Because you'll need to make climb cuts it is important that the instrument be firmly secured to prevent it from moving during routing. And of course it is important to keep a firm grip on the router when making the climb cuts.
The rule of thumb here is to always move the router "down hill". So, starting at the upper bout, first route down hill to the neck (this will be a conventional cut if the neck is pointing to the left), then reposition the router at the apex of the upper bout and route down hill to the waist (this will be a climb cut). Next, do the same thing from the apex of the upper bout, cutting down hill in the direction of the tail end, repositioning the router at the apex of the bout, then doing a climb cut down hill to the waist.
The basic idea is to use the knife to incise the top to follow the line of the binding channel and to continue it past the edge of the heel about 0.25". Ideally you would have some nice tool that could be used to follow the curve, but I usually just use the bent binding, positioned on the top to continue the curve. Hold it in place with one hand then gently scribe the top with a sharp knife, not too deep. Take the binding away and assess your mark. If it is in the wrong place just try again - since the mark is shallow it can be scraped away later. When you've got it in the right place then carefully deepen the cut, positioning the knife so that, if it slips, it will cut into the waste and not into the top. When you have done both sides of the neck it will look like this.
Now mark the ribs in a similar fashion. Here, use a flexible ruler and align it with the bottom of the channel, pushing the end of the ruler up against the heel. Scribe a shallow knife line as above to continue the line of the channel right up to heel. If this looks good, deepen the cut, but be aware you are cutting with the grain so do not split the wood.
Cut out the waste with a chisel. You'll need a miniature chisel for some of this work.
Note that the channel extension goes into the heel a bit. To be sure you get a tight fit, dig out the channel up to the heel, place a bit of binding in the channel butt against the heel, then mark the outside surface of the binding on the side of the heel. When you excavate the channel into the heel, use this mark as a guide. As mentioned, dig in about 0.25". This will insure the ends of the binding are held tight and will give you a bit of play for aligning the fretboard once it is put on.
Cutting the slot for the bindings at the heel on the back is basically the same as for the top, except here you only make one slot straight across. Since you can get close to the heel with gramil or router on the back, laying out the cut is a simple matter of setting a straight edge along the channel ends and marking the cut. Deepen it once you're satisfied it is in the right place. Then mark the bottom of the channel on the ribs, as described above for the top. When all is ready the channel is chiseled straight across.
The finished channel on the back looks like this:
Cut both plates as close as you can to the heel. Then, using the gauge block, reset the gramil for the depth of the purfling channel and use it to cut a line for the bottom of the channel. Note here you are cutting into the side wall of the binding channel.
If you are using a router to do this work, the process is exactly the same as for cutting the binding channel. Select your bearing, set the depth, cut a purfling channel in the gauge block, and check the fit of the purfling strips. When you've got a good fit, you can route the purfling channels in the plates.
As with the binding channels, if you are working on an instrument with the neck attached already you will not be able to cut the purfling channels all the way around. The ends at the heel will have to be done by hand, using the same tools and methods described for the binding channels. Here's a picture of the ends of the purfling channel on the top marked with a knife.
And, after marking, the waste is chiseled out using the tiny chisel.
Now the binding and purfling channels can be cleaned up to prepare them for gluing. The simplest tool to use is a small rectangular file with a safe edge.
A scraper can also be used to good effect.
In any case, check by dry fitting short off cuts of binding and purfling into the channels. The place where most of the fussy fitting is going to be is in the waist.
There are four pieces of binding to be glued in. The easiest place to start is with one of the top pieces, because the top pieces have to join perfectly at the tail end but the fit at the neck end is not too critical because this end will ultimately be covered up by the fretboard. Prepare to bend by dry fitting a piece of top binding into its channel, starting from the waist and working out to the tail end. When you get there, mark the binding a bit longer than at the center seam of the top, and then cut it at that mark. Temporarily tape it down here, then work your way back, dry fitting the binding into its channel, until you reach the end of the binding slot at the neck end (or, if the slot has no end, at the centerline of the top under the fretboard). Mark here, too, and saw (or just snip) the binding piece to length. If you find anyplace along the way that requires any more pressure than what you can apply with the pinkie finger of your off hand to press the binding into the channel, the binding should be re-bent in that place to make it a better fit. You can bend these kinds of touch-ups on the bending iron dry.
After getting the binding strip in order, do the same for the purflings. If you have more than three strips, tape one end together with a narrow piece of masking tape. Dry fit from the neck end of the channel all the way to a bit past the centerline of the top at the tail end. Snip the strips off here. Don't try to get a perfect fit - leave these a bit long.
If you will be using hide glue, now is the time to heat up your glue pot. The binding will be held in place with tape while the glue dries. To move the gluing process right along it is best to prepare a large number (about 30) of short (approximately 2") pieces of tape, and line them up so that you can just pick them off as you need them. I stick mine along the bottom edge of the workbench and on the vise handle.
Although it doesn't really matter I like to begin gluing from the neck end. And no matter what type of glue you use you should probably limit yourself to gluing no more than about 4" down at one time. Begin by brushing glue into the binding and purfling channels from the start of the channel at the neck end, going about 4" along. Splay the purfling strips with your fingers and apply glue to them, again about 4" along.
Now un-splay the purfling strips with your fingers and press both bindings and purflings into their channels, being careful not to let them slide around along their length. With one hand anchoring everything at the starting point, take a rag in the other hand and wipe along the glued length, squeezing out excess glue while pressing the strips all firmly into place. With the surface glue wiped away it is easy to assess if everything is in the right place.
Make a quick count of the purfling strips to be sure none have submarined under the rest. If you need to make any corrections do so quickly while the glue is still workable. Once you are satisfied with the application you can begin taping everything down. Take one of the tape strips and stick the center of it to the outside edge of the binding at the starting point. Then with one hand grasping one end of the tape and the other hand grasping the other, pull it tightly into place and stick it down to the top plate and the ribs. Wipe up any glue squeeze out and then apply the next piece of tape in the same way, next to the first piece and about 1/4" from it. Continue taping like this until you are close to where you left off with the glue.
Continue gluing, wiping and taping short sections until you have completed the entire side.
Be particularly careful with the waist because this is the area where it is most likely that the binding or purfling will gap. Use more tape strips here to really hold things in place.
Let the glue dry overnight before working on the other side of the top. When the glue is dry, carefully remove the tape strips. The tape should be removed so you are pulling it off the top across the grain, no matter which piece of tape. If you pull it along the grain you risk pulling up fibers from the top, leaving depressions which will be difficult to fill. If you find you are pulling up fibers, stop, pull the tape from the other direction, trying to keep the damage to a minimum. If you've pulled up fibers but they are still attached to the top and you can un-stick them from the tape, it may be possible to carefully re-glue them back down for an invisible repair.
With the tape removed you can assess how well you glued everything down. It is not uncommon to have some gaps. If you don't have too many and if they are small you can fix these by heating up the binding at the gap on the bending iron to soften the glue, and then clamping it into place with a clamp. If this doesn't work or if you've just got too many, you may have to remove the strips and try again. Usually the best way to do this is to simply route the binding off. You saved your gauge block right? use it to set up the router or gramil if you need to do this operation.
Small gaps here and there can be filled later in the process.
After the tape is removed you can proceed to the other side of the top. Here, the binding and purfling will be applied from the tail end up to the neck end. The first thing that needs to be done is to trim the tail end of the existing binding and purfling square so that a nice clean butt joint can be achieved with the to-be-applied strips. Mark the purfling and binding tops with a knife mark, in line with the center seam of the top. Continue that line down the side of the binding. Now trim the end nice and square using a small razor saw.
Of course, you can't saw all the way through binding and purfling, you can only saw at a diagonal, being careful not to saw into the ribs or the top plate. After you have sawn as far as you dare, finish this up using a small chisel.
Now cut the binding strip approximately to length as was done for the first side of the top, dry fitting starting from the waist and working toward the tail end. But on this piece, make that tail end mark accurate and then cut the strip nice and square on the mark. Check it against the piece that is already glued down, and trim it as necessary to get a nice clean butt joint.
Now dry fit the binding again, working from the tail to the neck end, and mark and trim this end too, but leave a bit extra. The purfling strips are trimmed to length just as they were for the other side of the top. Be particularly careful to be sure you will be able to get a clean butt joint with all the purfling strips. Get your tape strips and glue ready and you are ready to glue down this side of the top binding and purfling.
Here we begin the gluing a little differently than was done for the first strip. We begin at the tail end and the most important thing is to get nice clean butt joints between each of the purfling strips and also the binding. I find that after applying glue to the channels and the splayed purflings, the best approach is to slide each purfling strip into place one at a time, followed by the binding strip to hold everything in place. Then wipe with the rag toward the tail end, cleaning up any surface glue and forcing the strips tightly into place. Now place a couple of piece of tape here to keep everything in place. Do not tape right over the joint - you want to be able to see it. When you are sure you've got a solid butt joint here put a piece of tape over it, then continue to glue, wipe and tape down the strips one section at a time.
When you get near to the end, dry fit the last section into place and clip the strips to length.
Then apply glue to the final section, wipe, tape, and let dry overnight. When the glue is dry, remove tape as for the first side of the top and do any touch ups using bending iron and clamps as are necessary.
This would be a good place to discuss why the above instructions have you do the two sides of the top differently. In fact in my own work I do both sides exactly the same, trimming the tail end of the binding exactly and starting from the tail end and working up. But if you are reading this you probably either have never done this operation before (or are not yet comfortable in how you do it). Doing the first side without worrying about careful placement of the ends of the binding gives you one less thing to worry about while you gain valuable experience. When this operation is second nature then you may want to switch to doing both sides in the same manner.
The back is done in much the same way as the top. But consider that both ends of the strips on the back have to end in neat butt joints, and it is next to impossible to accurately trim the strips before gluing so that the length comes out perfectly at both ends. So my basic strategy is to trim the starting ends of the strips perfectly and leave the other end a bit long so it can be fitted later. I always start at the heel end. If the neck is off the body then it really doesn't matter, but if the neck is attached then at the heel end you are working in a slot where it is simply more difficult to work. So I trim the heel end of the strips and start at the centerline of the back at the heel.
Work your way to the tail end.
Yeah I know, you can't see much in that photo because my big head is in the way - my vision is poor and I need to get real close to the work.
After the glue is dry and the tape is off, trim the binding and purflings to the centerline of the back at the tail end. Then do the other side, starting at the heel with a clean butt joint. I will generally glue this last side within a few inches of the end but leave it unglued. The fitting of this butt joint takes a little more time than I am usually willing to do while I've got wet glue and tape all over the place. Once the glue is dry and the tape is off I'll turn my attention to dry fitting the pieces for this final butt joint. When it looks good the last few inches of this side are glued and taped and the glue allowed to dry overnight.
After all bindings and purflings have been glued they must be trimmed flush to the surfaces of the plates and the ribs. It is often the case that either or both bindings and purflings stand proud of the plates a bit, and in these cases it is usually best to trim them down with a small plane to near flush.
Be careful not to plane into the grain on the bindings. Check the runout direction before planing. Also, don't plane straight across any of the butt joints because you might pull up some strips that way. When you are near the plate surface, switch to a card scraper.
Scrape flush with the surface of the plates and also with the surface of the ribs. Be careful not to tilt the scraper blade when scraping the bindings where the fretboard will go. If you cut the bindings too low here there will be a gap between the underside of the fretboard and the top of the bindings. It is best to check for level here with a straight edge as you go.
Scraping will reveal any places where there are gaps between the bindings and purflings and the plates and ribs, and will also reveal gaps in any of the butt joints. All of these can be repaired now. The first step is to dig out any glue accumulated in the gaps. Do this with a scalpel and don't cut into any wood in the process. Larger gaps can be filled with splinters of wood from cut offs from top, back and rib material, which you have been scrupulously saving during construction of your instrument. Smaller gaps are generally best filled with a putty made of wood dust and a little glue, or you can use lacquer fill sticks for this job.
Gaps at the butt joints are best filled with small pieces of binding or purfling. I will fashion thin chisels by grinding an edge on feeler gauge blades of the same width as my purfling strips, and use one of these thin shop-built chisels to chisel out a short wedge of material over the gap. A similar wedge cut from saved purfling material is then glued into place, filling the purfling gap. There shouldn't be any big binding gaps. Smaller binding gaps can be puttied. After any repair work is done, use the scraper to level things off again, and the binding and purfling installation job is done.