MIMF

Hi, All.

Here's my process for binding side ports. It's just how I am doing it after 5 trials. The next time will be on my current guitar builds. I'll probably change it over time but this is what's working for me now. I am a former teacher so I am going to show too much detail. I can't help it! Sorry about that.

It's starts with this form I made. It's 6 layers of 3/4" plywood that is a tapered ellipse. I don't know what the mathematical name for it would be. Elliptical cone maybe?

It has about a 2º taper. I did the taper and shaping on my disk sander.

Then I trace the ellipse on the side. The pencil line doesn't need to be precise at this point.

Next is drilling a hole and cutting out the ellipse well within the line.

(Continued in the comments.)

Once I have the hole I will use a file to shape it a little.

I shape it with a file until the form fits into the hole to about here.

Then I put self-adhesive sandpaper on the form.

Here I'm starting to use the form to shape the hole. It's like a perfectly shaped rasp.

As I work the sandpaper on the hole the form fits farther into the hole. I move the sandpaper and keep shaping.

(Continued)

I keep shaping the hole all around until the form fits like this without the sandpaper.

I now have a very nicely shaped elliptical hole with smooth sides that are tapered to match the form.

Now that the port is ready for binding I'll start making that. For these trials I started with a nice piece of curly maple from my stack.

I cut thin strips on the bandsaw. I believe that sawn veneer bends better than sliced. There are no micro-cracks from a slicing process. I cut the strips to about 1.5 mm (0.060").

I got a nice set of pieces from this stick.

(Continues)

Then I use the ole painter's tape and CA glue trick to attach them to a thin batten board.

Then it's off to the drum sander for thinning. I first get one side clear of saw marks. Then flip them for final thinning to size.

I have tried several thicknesses. I found that anything between 0.5 mm and 0.7 mm (0.020" and 0.028") will bend well. I tried thicker pieces with limited success. Every trial in my target range bent well.

All sanded and ready for bending.
The next step is to spray some Super-Soft on them and put them in a plastic bag. The directions on the bottle are for flattening veneer sheets. I figured putting them in between paper and board and clamping them was not necessary and that is correct for what I'm doing. I just soak them, put them in a plastic bag, and let them stay there overnight.

(Continues)

Now we have the actual bending. I think a video would be much better than trying to explain what I do. In the video I'm using a heat gun on it's low setting. The high setting will burn the wood. The low setting provides plenty of heat.

https://youtu.be/OAT0_M44UhU

I do this for a good set of strips. I also bend some black veneer strips. I don't bother using Super-Soft on these, they bend easily.

I let them sit taped up until they are fully dry. I think I left them overnight this time. They retain their bends well.

Then I glue them together in this order.

I use the form again for the gluing. I put the laminations on the form and wrap them tightly with 3M auto-body tape. This is stretchy and compresses the binding well. I don't have a vacuum system and I'm not sure it would work well at this size. It might be better, I really don't know.

Here's the laminated binding after the glue sets and I take it off the form.

(Continues)

The trickiest part of the process is cutting and shaping the scarf joint. I do this with the form in the side port hole. It's a cut-and-try procedure and is fussy. However, since the port hole is tapered there is some leeway and getting close seems to be good enough. Then I use the form as a wedge clamp to glue the binding to the port. The joint should be very good as the form was used for all steps. I'm getting a nice bead of squeeze out all around.

I made the strips about 7/8" wide as that was the width of the stick I had. It should work down to even 1/2".

Then I pull the form out after the glue sets and start trimming the excess.
Once I flush the binding I shape it with a slight round over. I do this with sandpaper. Adding some oil to the trial lets me see if I have success.


(Continues, just one more time!)

Here are some glamour shots of the final shaped binding.

Since this was all an experiment I am very open to suggestions on improvements to this process.

Thanks for giving this a look.

-Eric


(All done!)

Wow! Great process Eric. I don't have anything to add.

Barry Daniels wrote: ↑Tue May 30, 2023 6:07 pm Wow! Great process Eric. I don't have anything to add.

Thanks, Barry. That means a lot.

-Eric

The tapered plug for shaping, laminating and gluing is genius.

Thanks for the tutorial. I know how much work that can be.

First off, that looks great.
Second, I echo Barry, that’s a great process.
Third, that is a well-produced tutorial. Clear and thorough.
Thank you!

Fantastic tutorial. I am thinking of using elliptical soundports on both the bass side upper bout and the side of my next archtop, so this is extremely helpful. I am trying to figure out which side to put the side port seam of the binding, towards the top of the guitar or the back. Initially I was thinking top, but then I reasoned that when the player looks down, it will be right there, so maybe back. I think if one were to use darker binding the seam would be even less noticeable, but yours looks very nicely done. Thanks for your educational efforts.

Great work Eric. There's more than one way to skin a cat.

Great tutorial thanks! Nice clean work too!

Barry Daniels wrote: ↑Wed May 31, 2023 8:28 am The tapered plug for shaping, laminating and gluing is genius.

Thanks, Barry. I don't know where I got the idea but I suspect it has been done like this before.

Barry Daniels wrote: ↑Wed May 31, 2023 8:28 am Thanks for the tutorial. I know how much work that can be.

I used to this for a living for my students. I had to explain complicated computer programming concepts to confused young adults. This one was really fun to do.

-Eric

Karl Wicklund wrote: ↑Wed May 31, 2023 9:20 am First off, that looks great.
Second, I echo Barry, that’s a great process.
Third, that is a well-produced tutorial. Clear and thorough.
Thank you!

Thanks, Karl. A compliment from a fellow teacher is a treat.

-Eric

Christ Kacoyannakis wrote: ↑Wed May 31, 2023 10:10 am Fantastic tutorial. I am thinking of using elliptical soundports on both the bass side upper bout and the side of my next archtop, so this is extremely helpful. I am trying to figure out which side to put the side port seam of the binding, towards the top of the guitar or the back. Initially I was thinking top, but then I reasoned that when the player looks down, it will be right there, so maybe back. I think if one were to use darker binding the seam would be even less noticeable, but yours looks very nicely done. Thanks for your educational efforts.

Thank you, Christ. I am still debating which side gets the scarf joint. That's why I did trials on a trial side so I could hold it like a guitar and see which way I liked better. I'm undecided. I also did this with a light wood on purpose. I always do trials of new things in light woods. When learning to do hand-cut dovetails I worked with pine. If you can make nice dovetails in pine then hardwoods are almost easy. Once I decide on what wood I'm using for the bindings on my current guitars I plan on using the same on the ports. Or at least something similar.

-Eric

Darrel Friesen wrote: ↑Wed May 31, 2023 11:58 am Great work Eric. There's more than one way to skin a cat.

Thanks, Darrel!

Bryan Bear wrote: ↑Wed May 31, 2023 3:19 pm Great tutorial thanks! Nice clean work too!

Thanks for both comments, Bryan!

Super nice, Thanks for the tutorial