Mitered Purflings - Luthier Tips du Jour Mailbag
In this episode, luthier Robbie O’Brien demonstrates the step-by-step process of meticulously mitering purflings on a guitar, providing clear instructions and valuable insights into this intricate technique.
Video Transcription
[on-screen text reads: Luthier Tips du Jour Mailbag]
Mailbag question: Can you show us the process for doing mitered purflings around the end wedge?
Robert O''Brien: Today's Tips du Jour Mailbag question comes to us from Spain. "Robert, in your online acoustic guitar building course, you show how to install bindings and purflings. However, on my guitar, I want to do mitered purflings around the end wedge. Would you be willing to show that process? Miguel in Spain."
Sure. Miguel. Now a word of caution. Anytime you dress up that guitar in the way of bindings, purflings, sound ports, arm bevels, anything you do to dress it up, that's where the eye goes. So if you're going to do it, make sure that you can execute it properly and you do a good job. A bad binding job will make an otherwise great guitar look really bad in a hurry. So make sure you can execute it properly. With that said, let's go to the bench. I have a guitar on my bench right now that's going to get mitered purflings around the end wedge.
How to do mitered purflings around the end wedge
So Miguel, here's just one way of doing it. I'm sure there are other ways. When I'm cutting my binding channels, I've got a step channel here. I cut this small channel here for the black, white, black that's going to go in here. That will be seen looking down from the top. Then I went ahead and cut the channel for the binding and I cut that to the correct depth. The next thing I did is I lowered my router bit, just a little bit more in my LMI binding cutting jig. And cut just a little small channel, just a little bit deeper there so that the black, white, black can be stuffed in when I install the bindings. However, I stopped that short of the end wedge and now I'm going to have a little bit of hand work to do to remove the rosewood up to the black, white, black.
Then I have to miter that black, white, black so that this one comes into it like that. Now it sounds like a lot of work and sometimes it can be, but let me show you how I do it. So I'm just going to come in with a chisel, one that I've got a nice mirror finish on the back and you'll see why in a minute why I did that. And I'm going to come in and just remove that little piece of rosewood. So I want the channel to continue right up to that black, white, black. So come in there and just place your chisel in there and remove that little piece there. If you need to, come in from the side just a little bit following the depth of your channel, be careful not to go too far and damage the black, white, black.
Once that's done, then we need to miter that little piece of the purfling there. The next thing you do is come in and place your chisel on the edge of the purfling line there. And now you know why I want the mirror in there. I can turn that mirror until I see that I've got a perfect 90 degree angle. I want to see that purfling come into my chisel and go out the other side. Let me move my chisel over and see if I can illustrate this a little bit better. Obviously, I'm not going to cut there because I would cut into the side.
But you can see that purfling line as it comes into your chisel. And you can cut a perfect 90 degree angle there, or 45. It would be a 45 that I'm cutting. But in the mirror it looks like a 90 degree angle. So I'm going to place the chisel on there where it needs to be, and just make the cut. Make sure that you're straight up and down on your chisel. Also, make sure that your angle is going the right way. Don't cut it back the wrong way.
So now I've cut a 45 degree angle on that side. Now I'm going to take my purfling line and do the same thing on it so that it matches this angle here. So the miter the purfling. I'm going to use the mirror trick again in my chisel. Just place it over the top of the purfling that you want to miter and look in there until you've got an exact square left or right turn. It's going to be 90 degrees in the chisel, but it's going to be 45 degrees on your purfling. So once you're happy with the angle, go ahead and make the cut, but make sure your chisel is standing straight up and down.
So make sure that you test everything to check your fit before you get out your glue bottle. And that looks like it's going to come together nicely once I put it together. So Miguel, this guitar is a cutaway, so I'm going to have twice the fun. I've already cut out this part. This is all done by hand. I'm going to bind the top, bind the back, leave my bindings and purfling sticking out here long. Then come in just 45 with your chisel both ends and install that piece right there. And that way the bindings connect the top and back. It looks really sharp if you can execute it properly.
Another piece of advice
So Miguel, here's one other piece of advice for you. When it comes time to install your bindings and purflings, you may want to choose a glue that has a longer open time. LMI sells a product called Fish Glue, has a super long open time, it's water soluble, allows you plenty of time to get all those miters and everything fit properly as you're installing.
Another option would be to use the CA glue method of installation where you put everything in, tape it all together, and then wick in CA glue from the top and the sides to help hold everything in place. That way you fit everything dry, everything fits before the glue bottle even comes out.
So Miguel in Spain, thank you very much for your question and I hope that seeing it done in my shop has opened up a few possibilities and ideas for you to do it in your shop. And happy building.
[on-screen text reads: More Luthier Tips and online courses available at www.obrienguitars.com. Private and small group guitar building and finishing instruction available.]
