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Building a bowlback mandolin

Posted: Wed Apr 04, 2018 9:25 pm
by Paul Montgomery
I've built a few simple instruments but I'm finally stretching myself and attempting a bowlback mandolin. I have a lot of wood working experience but this looks like a challenge.

I used to take photographs of my projects but for the last few months I've been learning how to do video and so I've just finished the first video of some prep work that I've been doing. I fully expect this to take a while, but I'll keep this thread updated as I progress, and I gladly invite any advice along the way.

TIA

Paul M

http://openwoodshop.com/instruments/mandolinprep1.php

Re: Building a bowlback mandolin

Posted: Wed Apr 04, 2018 10:03 pm
by Christ Kacoyannakis
I have built several Greek bouzoukis, which are basically a bowl back mandolin with a longer neck. I built my first one in 1980, with the help of a local lute maker. There are a few things you need to adjust. On a lute, the bowl is basically a semicircle in cross section. On a mandolin, the bowl is not semicirclular. There is a flat section at the very back (so it sits flatter on your stomach), then it makes a sharp turn with a flatter side leading into a wide rib at the top of the bowl, where it meets the soundboard, which allows the instrument to sit on your leg without slipping around so much.

The key thing to remember is that the sections of the bowl (the ribs) are liking slicing a pear in wedges. You slice straight down, and it doesn't matter the shape or curvature of the pear skin, the edge of that slice is flat.

I documented a bouzouki build on my blog, www.kacoyannakis.com/blog that you might want to check out. Feel free to ask me any questions. I would be glad to help you any way I can.

Re: Building a bowlback mandolin

Posted: Wed Apr 04, 2018 11:38 pm
by Paul Montgomery
Very cool blog. I'll definately be coming back to that, thanks.

Paul M

Re: Building a bowlback mandolin

Posted: Fri Apr 06, 2018 9:20 pm
by Clay Schaeffer
Some of the bowl backed (Neapolitan) mandolins I've had were double skinned - they had two layers of veneer thickness staves off set from one another. This probably made it easier to bend the staves and made a stronger bowl.

Re: Building a bowlback mandolin

Posted: Fri Apr 06, 2018 11:26 pm
by Paul Montgomery
I've thought about that but didn't realize it had been done. It seems like they would have to be narrow staves for that to work.

Paul M

Re: Building a bowlback mandolin

Posted: Sat Apr 14, 2018 7:37 am
by Clay Schaeffer
The staves generally were narrow. Veneer will wrap around curves some, so a wider stave could work this way also. The staved part of the back seemed to have a simple circular cross section with the added side pieces giving the final shape and added depth.

Re: Building a bowlback mandolin

Posted: Sat Apr 14, 2018 12:11 pm
by Bill Raymond
Comparing photos of bowlback mandolins, front and side, I doubt that they "have a simple circular cross section", though I could be wrong about this.

Re: Building a bowlback mandolin

Posted: Sat Apr 14, 2018 5:04 pm
by Bob Francis
Nice blog Christ

Re: Building a bowlback mandolin

Posted: Sat Apr 14, 2018 8:29 pm
by Christ Kacoyannakis
Thanks!

Re: Building a bowlback mandolin

Posted: Sun Apr 15, 2018 11:31 pm
by Paul Montgomery
So here is part 2 of the Bowlback Mandolin project. It only gets more interesting from here! Because this is the first one I'm still just working things out. I'm sure as time goes on I'll get more 'sophisticated' in my approach.

The videos are a LOT more work than plain images like I used to do, but as long as people keep liking them - I'll keep making them.

http://openwoodshop.com/instruments/mandolin2.php

Image

Paul M