Binding a side sound port

JJohansen

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Hi everyone,

I've just spent two days trying to bind a side sound port. My design called for a b/w/b purfling then a 1.5mm ebony binding. The shape of the port is an oval roughly 45mm long and 38mm wide.

Cutting the hole itself was pretty straightforward, I made a routing jig and a template bearing bit. Then the real fun began...

I found in next to impossible to bend 1.5mm ebony to the radius I need. I can get close, but not close enough to get a even match with no gaps. Trying to get the ebony to take the side bend (to match the curvature of the upper bout) was completely impossible. The purfling was easy enough to shape, but again, the side bend threw everything off.

I ended up with a solution of laminating my purfling and binding around a "plug" form. Rather than trying to bend 1.5mm ebony, I laminated two .75 mm strips, roughly bent to shape. I handled the side bend by making my purfling\binding laminate 15mm tall. Rather than trying to bend in two axis, I glued in this taller assembly and filed it down to follow the curve of the upper bout.

Although my end result was good, I'm sure there must be a better way?

Thanks! Josh
 
I don't bind my side ports for this very reason. I saw a shot of Peter Lieberman's operation and I think that he does the soyndport before bending. It would make sense to do this... The first guitar I ever made had 3mm ebony bindings which I made by laminating. Was the only way to do it...
 
If I bind the soundport I use .030 black fiber. If I didn't use that I would use ABS. I just don't need the grief of trying to bend ebony that tight.
 
If I didn't use that I would use ABS. I just don't need the grief of trying to bend ebony that tight.

Add me to the list of discouraged ebony benders. It will get close and then... crack! I've given up on it on tight bends... Yeah, use black ABS like Michael says instead. Looks like ebony (well sort of) and sure bends easier. Nobody will ever know or really care. Except you.
 
Josh- Hope you're doing well over there. Here is a different way to bind sound ports. Takes only a few minutes and makes a foolproof tight fit. With a little imagination you can adapt it to any size or shape of port. The method uses one of those cheap brass inlay kits found in all the catalogs. It comes with only 1 size of bearing, which does not allow you to add purfling, but people still love the look. They can't figure out how you bent the wide ring. If you have access to a small metal lathe, you can easily make additional bearings which opens up the possibility of adding purfling lines. I've done that and some extra bearings are shown in the photos. Just get the kit if you are interested and I'm sure you can figure it out. I do the inlay, cut out the sound hole itself, and then bend the side. Often I will add blue tape across the whole inlay area on the inside and outside of the side. Don't know if it actually helps. I made my first plexiglass shape template by hand and then had a laser guy make me another one. My handmade one was just as good. Only other tool needed is a router with a base that accepts standard bushings. I love the new 1 1/4 H.P Makita routers for stuff like this.Recognize the guitar side wood? My favorite Hawaiian hardwood! You have to have lived here to know. Have a good one.--Bob
 

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Try using Indian ebony, or Rocklite, or black fiber in layers.
You will have to re dye the black fiber with black dye to get a black look as it looks grayish when sanded.
 
I was wondering if the the port was cut before bending if the side would bend properly without distortion?
 
I would be pretty durn scared the side would break at the sound port when bending the side
 
I only do SSPs occasionally. They are never bound.
I assemble the ribs (sides, blocks and kerfing), double the side thickness at the location of the SSP, then cut through the side and reinforcing together.
Hand bending of a side with a pre-cut SSP, for me, would be an invitation to disaster.
 
Hey Bob, I worked out a way to add any width purfling when using the brass inlay system. All I do is cut the hole normally, then use very thin two side tape to stick the purfling to the inside of the router template, then cut the plug. The plug is automatically cut to accommodate the purfling width. The tape seems to add just the right clearance to allow for glue. Probably a basic procedure to most people, but for me, a victory!
 
Josh- That sounds interesting. I'll try that. My lathe is in for gear repair, but I was planning on turning new various sized bushings to accommodate purfling. Your way would be simpler if I can get it to work for me. Thanks for the suggestion.BTW, your last suggestion for the resew fence has been a real game changer for me. Too bad I did not know about it when there actually was koa around! Hope you're doing great!-Bob
 
Brian Griffin of Griffin ukes in Bellingham Washington sells side port linings he gets cut by a laser. Not sure what woods he has.
I bought one of Brian's rings for my first uke. I want to say it was Cocobolo, but I'm not 100% certain. Hardest part was sanding a curve into it to fit the contour of the upper bought, then accurately tracing around it to ensure a good fit. It made for a very nice addition to that uke.
 
One thing about these various systems that use some sort of wood cut-out around the edge of the sound port. I thought one of the purposes of binding was to cover the end grain on the top and back. I would assume that the same is true of a side sound port, where the binding should cover the end grain where the hole is cut in the side. These various wood cut-out methods leave end grain on the sides of the port.

I wrap layers of pre-bent thin veneer around the edge, glue a section of it in place with CA using a piece of teflon grill-mat sheet to keep from gluing the fingers (real handy stuff when working with CA, and real inexpensive), perhaps using a small wedge against the hole, and then on to the next section. I have some thick black veneer that I use for the outer edge, a bit more difficult to bend and muscle into place, but not bad. I do all this after gluing a cross-grain reinforcing patch on the inside but before putting in the linings so it is real easy to sand the protruding veneer edges on the inside flush on the spindle sander.
 

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Josh- I tried your idea of adding the purfling to the template for routing. I do have thin double stick ,the 468MP used for pick guards, but I tried just using 1/4" blue tape and it worked fine. Gonna try scotch tape too. I was a little too clumsy dealing with the double stick on such a thing piece of purfling. Anyway, thanks for the idea.-Bob
 

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One thing about these various systems that use some sort of wood cut-out around the edge of the sound port. I thought one of the purposes of binding was to cover the end grain on the top and back. I would assume that the same is true of a side sound port, where the binding should cover the end grain where the hole is cut in the side. These various wood cut-out methods leave end grain on the sides of the port.

I wrap layers of pre-bent thin veneer around the edge, glue a section of it in place with CA using a piece of teflon grill-mat sheet to keep from gluing the fingers (real handy stuff when working with CA, and real inexpensive), perhaps using a small wedge against the hole, and then on to the next section. I have some thick black veneer that I use for the outer edge, a bit more difficult to bend and muscle into place, but not bad. I do all this after gluing a cross-grain reinforcing patch on the inside but before putting in the linings so it is real easy to sand the protruding veneer edges on the inside flush on the spindle sander.
That looks easier than my method. which has been to use my router and templates to cut an oval ring, sand it to the profile of the upper bought, trace around it, then roughly cut the hole in the side, followed by slowly nibbling away the remainder until the ring slides in place. Then once it is glued, it has to be sanded flush inside and out. It looks good, but it's a lot of work. I think next time I'll try something like your method.
 
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