Wilborn Guitar Attempt
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Kevin Sjostrand
- Posts: 3941
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- Location: Visalia, CA
Re: Wilborn Guitar Attempt
Bruce I concur with all that you said
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scamp
- Posts: 345
- Joined: Sat Mar 26, 2022 8:19 pm
Re: Wilborn Guitar Attempt
I did some research on higher temperature glues/epoxies
They exist but are expensive and/or difficult to work with.
I believe the bottom line is most glues are not rated for temperatures required for bending but some hold well enough so they don't separate during the bending process and then reharden when cooled down.
So... it sounds like Titebond III, Clear Gorilla and CA won't separate at bending temperatures ( typically ).
You might need to be careful about using CA on some wood as it might stain.
They exist but are expensive and/or difficult to work with.
I believe the bottom line is most glues are not rated for temperatures required for bending but some hold well enough so they don't separate during the bending process and then reharden when cooled down.
So... it sounds like Titebond III, Clear Gorilla and CA won't separate at bending temperatures ( typically ).
You might need to be careful about using CA on some wood as it might stain.
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scamp
- Posts: 345
- Joined: Sat Mar 26, 2022 8:19 pm
Re: Wilborn Guitar Attempt
Today I decided to try and make the arm bevel support lining.
Here is a picture of the part from Ben's web site.
I started with a 1 inch thick piece of Spanish cedar which was 6 inches wide ( two 3 inch pieces glued together ) to make the support. A lot of waste but I can use the left over for other purposes.
The big challenge in making this lining is to get the curve of the support to match the inside wall of the guitar.
Not too bad if you have a CNC router but it's not something I can justify for an amateur shop.
Since I have a template I made for the mold I figured I could use it with a flush cut router to make the curve.
Unfortunately, this curve is not quite right as it matches the outside surface of the guitar, not the inside wall which is 0.12 inches thick. So.... I did the following.
I used the template I had, taped it to the cedar plank and used a flush cut router bit to match the outside curve.
I then used the Stewmac binding router bit I had with a 0.12 inch bearing and routed a notch on one side.
I then used the flush cut router bit again with the bearing in the notch to rout off exactly 0.12 inches.
Worked well. Now just need to trim it down to the proper width. Probably do this later when I have the sides bent and glued together.
Flush cut routed with outside curve
0.12 inch routed notch using binding router
Flush routed again with proper inside curve.
Here is a picture of the part from Ben's web site.
I started with a 1 inch thick piece of Spanish cedar which was 6 inches wide ( two 3 inch pieces glued together ) to make the support. A lot of waste but I can use the left over for other purposes.
The big challenge in making this lining is to get the curve of the support to match the inside wall of the guitar.
Not too bad if you have a CNC router but it's not something I can justify for an amateur shop.
Since I have a template I made for the mold I figured I could use it with a flush cut router to make the curve.
Unfortunately, this curve is not quite right as it matches the outside surface of the guitar, not the inside wall which is 0.12 inches thick. So.... I did the following.
I used the template I had, taped it to the cedar plank and used a flush cut router bit to match the outside curve.
I then used the Stewmac binding router bit I had with a 0.12 inch bearing and routed a notch on one side.
I then used the flush cut router bit again with the bearing in the notch to rout off exactly 0.12 inches.
Worked well. Now just need to trim it down to the proper width. Probably do this later when I have the sides bent and glued together.
Flush cut routed with outside curve
0.12 inch routed notch using binding router
Flush routed again with proper inside curve.
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scamp
- Posts: 345
- Joined: Sat Mar 26, 2022 8:19 pm
Re: Wilborn Guitar Attempt
Starting to work on a routing template that will be used to make the proper cuts in the guitar top for the arm bezel and "comma" sound hole purfling and ebony. Not that easy to get the curves and interconnecting straight lines to flow properly. Decided to draw the curves on paper glued to a 1/4 inch MDF board and play with them until I'm satisfied. I figure I can then cut it out on a bandsaw and easily sand down to the lines using a spindle sander and hand sanding. Ultimately, the plan is to use this template with a flush cut router bit to make the final template using thicker MDF. I need thicker MDF for the final template since one side needs to hollowed out to match the 28 ft radius of the top ( so the edges of the template sit flat ). To do that I will need to rout out contours in the template. A problem for another day.
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scamp
- Posts: 345
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Re: Wilborn Guitar Attempt
This is for all the nurds out there ( which I am ).
Always struggled with how thick to make the top and back of the guitar.
For that reason, I sought out ways to help me with this task that were a bit more scientific than tapping and listening ( since I'm not exactly sure what I am listening for ).
In my search I found the Trevor Gore book and in it he has a way of calculating a target thickness for the top and back. For it to work, it makes the assumption that the guitar bracing has consistent stiffness and weight ( which is a big assumption ) but it does deal with the variability in the top and back wood density, stiffness etc.
So.... I decided to try it and come up with some target numbers. If your interested there is a very convenient calculator on the web. Just plug in the numbers and you get an answer. Check out
https://www.celestialinstruments.com/bl ... WLfkUyuTPw
To do this you need the top and back wood plates in a rectangular shape with consistent thickness ( to within 0.01 inch or so ). You also need a laptop running some free frequency analysis software called REW. This is to measure the resonant frequency of the panels in three different modes ( long grain, cross grain and twisting) by tapping them and analyzing the response. The data you need to enter is the following: Weight, length, width, thickness, and the three resonant mode frequencies, length of guitar box, width of the lower bout and the target resonant frequency of the panel in the guitar ( 75 Hz for the top panel and 55 for the back on steel string guitar).
Some photos below. BTW...My target thickness for the top is 2.66 mm and 2.21 for the back. We shall see.
These are the panels. I measured both of the top and bottom panels and averaged the results.
Screen shot of one of the REW tap responses. You can see the peak at 59 Hz.
My spreadsheet calculator results ( I put this together before I found the on line calculator).
Always struggled with how thick to make the top and back of the guitar.
For that reason, I sought out ways to help me with this task that were a bit more scientific than tapping and listening ( since I'm not exactly sure what I am listening for ).
In my search I found the Trevor Gore book and in it he has a way of calculating a target thickness for the top and back. For it to work, it makes the assumption that the guitar bracing has consistent stiffness and weight ( which is a big assumption ) but it does deal with the variability in the top and back wood density, stiffness etc.
So.... I decided to try it and come up with some target numbers. If your interested there is a very convenient calculator on the web. Just plug in the numbers and you get an answer. Check out
https://www.celestialinstruments.com/bl ... WLfkUyuTPw
To do this you need the top and back wood plates in a rectangular shape with consistent thickness ( to within 0.01 inch or so ). You also need a laptop running some free frequency analysis software called REW. This is to measure the resonant frequency of the panels in three different modes ( long grain, cross grain and twisting) by tapping them and analyzing the response. The data you need to enter is the following: Weight, length, width, thickness, and the three resonant mode frequencies, length of guitar box, width of the lower bout and the target resonant frequency of the panel in the guitar ( 75 Hz for the top panel and 55 for the back on steel string guitar).
Some photos below. BTW...My target thickness for the top is 2.66 mm and 2.21 for the back. We shall see.
These are the panels. I measured both of the top and bottom panels and averaged the results.
Screen shot of one of the REW tap responses. You can see the peak at 59 Hz.
My spreadsheet calculator results ( I put this together before I found the on line calculator).
You do not have the required permissions to view the files attached to this post.
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scamp
- Posts: 345
- Joined: Sat Mar 26, 2022 8:19 pm
Re: Wilborn Guitar Attempt
Spent the last week or so thinning and bending the wood for my laminated sides.
The sides have a 0.06 inch outer ERW layer, a 0.03 inch maple inner layer ( with the grain perpendicular to the rosewood ) and a 0.03 inch ERW inner layer. A bit worried that the maple layer will crack when I try and glue up the sides. The maple layer, unlike the rosewood layers, are not bent since the maple layer is made up of multiple pieces glued ( the glue joints won't take the bending hear). Since the grain is perpendicular to the long dimension of the sides it is floppy enough at this thickness so it will bend without breaking ( I hope ). To cover my bets, I also made a 0.03 inch maple layer with the grain running in the long dimension and bent it. If things go south when trying to glue the maple with the perpendicular grain I will just substitute the bent maple layer and keep going.
Also starting working on my headstock inlay.
Decided to make a diamond out of ebony with turquois purfling an inlay it in the rosewood headstock veneer.
Made three of them to practice my joinery.
Picked the best and inlaid it into the rosewood.
The sides have a 0.06 inch outer ERW layer, a 0.03 inch maple inner layer ( with the grain perpendicular to the rosewood ) and a 0.03 inch ERW inner layer. A bit worried that the maple layer will crack when I try and glue up the sides. The maple layer, unlike the rosewood layers, are not bent since the maple layer is made up of multiple pieces glued ( the glue joints won't take the bending hear). Since the grain is perpendicular to the long dimension of the sides it is floppy enough at this thickness so it will bend without breaking ( I hope ). To cover my bets, I also made a 0.03 inch maple layer with the grain running in the long dimension and bent it. If things go south when trying to glue the maple with the perpendicular grain I will just substitute the bent maple layer and keep going.
Also starting working on my headstock inlay.
Decided to make a diamond out of ebony with turquois purfling an inlay it in the rosewood headstock veneer.
Made three of them to practice my joinery.
Picked the best and inlaid it into the rosewood.
You do not have the required permissions to view the files attached to this post.
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Kevin Sjostrand
- Posts: 3941
- Joined: Sat Feb 09, 2008 8:06 pm
- Location: Visalia, CA
Re: Wilborn Guitar Attempt
Your inlay looks great
If the maple inner pieces break, don't sweat it using your bent pieces. I totally doubt there will ever be an issue with the grain all running the same direction as long as you have a good lamination with them all.
If the maple inner pieces break, don't sweat it using your bent pieces. I totally doubt there will ever be an issue with the grain all running the same direction as long as you have a good lamination with them all.
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scamp
- Posts: 345
- Joined: Sat Mar 26, 2022 8:19 pm
Re: Wilborn Guitar Attempt
Thanks.Kevin Sjostrand wrote: ↑Wed Apr 02, 2025 3:35 pm Your inlay looks great
If the maple inner pieces break, don't sweat it using your bent pieces. I totally doubt there will ever be an issue with the grain all running the same direction as long as you have a good lamination with them all.
I agree that the bent maple should work if necessary. The grain of the maple is significantly different than the rosewood. Additionally I believe the epoxy hardens the wood to the point it is difficult to pull it apart even across the grain.
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scamp
- Posts: 345
- Joined: Sat Mar 26, 2022 8:19 pm
Re: Wilborn Guitar Attempt
Finally got up enough guts to try and epoxy one of the three layer sides.
Good thing I tried this before on some scrap sides as the lessons learned helped a lot.
That said, it was still a bit of a struggle getting the proper layer of epoxy on the thin veneered side material and getting it all lined up. To help deal with any possible misalignment of the sides during the glue up I decided to trim only the thicker ( 0.06 inch ) layer to the approximate side dimensions and keep the inner ( 0.03 inch) and inside ( 0.03 inch ) layers 5 inches wide. I could then trim them down to the outside layer dimensions after they were glued.
Attached are some pictures.
Overall very happy with the results. I must say I was surprised how much epoxy seeped through the rosewood to the unglued outside and inside layers. I used thickener with the epoxy but maybe not enough. It was a bit of a chore to scrape and sand it off but in the end not too bad. Once scraped down the sides really are nice. Very stiff. Perfectly fit the guitar shape ( no spring back ). Sides are very flat. End thickness of the sides came out almost exactly 0.12 inches as expected. On to gluing the other side.
Good thing I tried this before on some scrap sides as the lessons learned helped a lot.
That said, it was still a bit of a struggle getting the proper layer of epoxy on the thin veneered side material and getting it all lined up. To help deal with any possible misalignment of the sides during the glue up I decided to trim only the thicker ( 0.06 inch ) layer to the approximate side dimensions and keep the inner ( 0.03 inch) and inside ( 0.03 inch ) layers 5 inches wide. I could then trim them down to the outside layer dimensions after they were glued.
Attached are some pictures.
Overall very happy with the results. I must say I was surprised how much epoxy seeped through the rosewood to the unglued outside and inside layers. I used thickener with the epoxy but maybe not enough. It was a bit of a chore to scrape and sand it off but in the end not too bad. Once scraped down the sides really are nice. Very stiff. Perfectly fit the guitar shape ( no spring back ). Sides are very flat. End thickness of the sides came out almost exactly 0.12 inches as expected. On to gluing the other side.
You do not have the required permissions to view the files attached to this post.
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Kevin Sjostrand
- Posts: 3941
- Joined: Sat Feb 09, 2008 8:06 pm
- Location: Visalia, CA
Re: Wilborn Guitar Attempt
Looks great. That's some pretty thick sides. Usual sides are around .085" plus or minus .005.
You might not need as thick a kerfing. Think about the weight too.
Glad it worked out for you. Were you able to use the cross grained maple?
You might not need as thick a kerfing. Think about the weight too.
Glad it worked out for you. Were you able to use the cross grained maple?