hand-carving bowlback mandolin from a firewood block?

[Bamboori]

I want to make a small bowlback mandolin. I'm by no means an expert, but as far as I've seen bowlbacks are usually made by bending strips of thin wood and glueing them together using a solid template for the shape.
The problem I have is that I don't have any access to a bandsaw (theres a public accessable woodworking workshop but theirs broke down) and buying ready-made layers is really expensive when you want anything but plywood or similar cheap stuff.

I will however visit my grandma soon, and as far as i know she has lots of firewood stacked up in a shed.
So my idea is that instead of using thin wooden strips, I will carve out three sections out of solid wooden blocks and glue those together.
I realize that this will probably take a looong time (also because I'll be mostly hand-carving) and will not look as smooth as when using the traditional method, but what do you guys think about stability and sound?
I will of course try to get the wood down to a few millimeters, but I will probably rather have it a little too thick than a little too thin. Also the surface won't be even, because you know. Hand carved.

Here's a small sketch what I think I could do:

I marked in blue what the finished piece would look like on the left and on the right the separation of the three pieces of wood.

Oh for the lid I will probably get some thin wood layers of a nice kind, because handcarving a sheet of wood is just too much work I think.

[billhay4]

This is done with some instruments, but.... Lots of negatives. It will be very difficult to do as you know. The chances of the body cracking later are very high. When it is thin enough to produce a good sound, it will be very fragile.
I wouldn't do it.
Bill

[Bamboori]

That's what I feared I will probably still try to do it as a side project just to see how it turns out.
As an alternative, would plywood be any better? The soundboard would still be a different kind of wood.

[CarlM]

The problem with carving the bowl from a block is that you end up with a lot of short grain where the bowl curves and that is extremely fragile. The staved bowls are thin bent pieces so the long grain runs around the curve of the bowl.

Plywood would have to be bent to avoid the same problem and commercial plywood has a lot of voids and a pretty weak inner layer unless you buy very expensive plywood. The higher grade plywood would be just as expensive as buying solid wood from a tonewood supplier and still not sound as good.

If you have access to a tablesaw, strips in a bowlback are narrow enough they can be resawed from board lumber using a tablesaw if you are careful then thicknessed.

If the cost of the wood is too much though, you still have to buy tuners, fretboard, tailpiece and possibly a bridge to get a usable instrument.

if you do not have a lot of shop experience you might want to get some help and instruction to avoid injury.

[GaryTimmons]

Hey, it's worth a shot, have fun doing it. The top will have a lot to do with the sound anyway. I'd avoid plywood. Continue doing more research in the construction end of bowl backs. I've seen a Youtube video about someone in Italy building as you proposed, entirely by hand. I'll try and locate it. It's always about having fun expanding vision.

[Tavy]

+1 on that not working well.

You don't need a bandsaw though - I would suggest you buy guitar sides (many suppliers will offer sides separately from backs) which will provide you with enough wood. You would need to thickness it down to approx 2mm to be able to bend it - if your nearby woodworking shop has a thickness sander then that's ideal. You can also use an orbital sander if the sides are not too thick to start with and reasonably easy to abrade (african mahogany would be ideal for experimenting with in this context), though you don't get a consistent thickness that way. And finally you can also use a spindle sander with a fence to thickness small pieces.

[Bamboori]

Actually I got everything apart from the wood on the way already :P
But that's a really good tip with the strip cutting from a block. Seems so logical when I think about it!
I do not however have access to a tablesaw, so I'll try with a handsaw, a steady hand and a cheap block of wood first.

I couldn't find the italy video yet, but I'll keep looking! Also maybe I should mention that it won't be a regular mandolin. It will have a smaller body (which will help if I carve it) and an extra string on the two higher notes. And I want to experiment with combining nylon and steel strings. But for now I should worry about the body I guess.

[Jacob]

Here's a saz with the body carved from a block of mulberry.



A mandolin carved from naranjillo.

[Bamboori]

Now that looks nice!
If I do pull it of I'll be sure to show you guys what it looks like.
I searched a little for guitar wood (I can't look for sides specifially because in german sides (Seiten) and strings (Saiten) are too similar so I always get strings when I search in shops) and it seems I just had the wrong idea about the wood price... the cheapest I could find was 60€ plus shipping. Maan, I'm just too poor for professional tonewood it seems :P
I found mahagoni planks for 60€/m² which is a little cheaper. It is only 2mm thick though. Will that be enough for the bowlback body or will it be too fragile?

[Marty Jacobson]

Wood for nice quality musical instruments does not need to be expensive! You just have to look for longer to find nice wood in the pile of cheap wood. Online tonewood sellers (with a very few notable exceptions), particularly the ones which show you the exact piece you will be getting, will charge $100-200 for a piece of guitar wood which you could match with a look through a good woodworking wood supplier at 10-20% of that cost.

[multidon]

Didn't Orville Gibson used to make his bodies from one solid piece of hollowed out wood?

[Marty Jacobson]

Didn't Orville Gibson used to make his bodies from one solid piece of hollowed out wood?

The back was one element, the sides were separate, but basically sawn from thicker stock. Below is a harp guitar:

[GaryTimmons]

Thanks Jacob for jarring my memory. The older I get.... So, what I was referring to as being in Italy was wrong. It was a Saz being built. Here is a link to the Youtube video. This segment was part of a longer video of different builders producing Saz's or is it Sazes.

https://youtu.be/3vUmbLfWZj4

[Jim Garber]

You would need to thickness it down to approx 2mm to be able to bend it - if your nearby woodworking shop has a thickness sander then that's ideal.

Would hardwood veneer work for the bowl ribs? Like this example which thickness of this maple looks to be 1.58". BTW You certainly don't need to have fancy wood for it to sound good. Maple Veneer

[DavidKOS]

Make a baglama, a "baby bouzouki".

Many are made with a body carved from a single piece of wood.

http://www.instructables.com/id/Bagl...tional-greek-/

[Tavy]

Would hardwood veneer work for the bowl ribs? Like this example which thickness of this maple looks to be 1.58". BTW You certainly don't need to have fancy wood for it to sound good. Maple Veneer

Regular veneer is 0.6mm which is way too thin. However, there are veneers sold either as "constructional veneer" or "saw cut veneer" which are thicker - and often just about right actually.

[ProfChris]

If this is a fun project to get a working mandolin, rather than an attempt at producing a "fine" instrument, then you could even use 1/16 inch birch ply for the bowl. This should bend without any heat, as it's quite flexible, but once made up into the bowl shape and braced internally will be plenty strong enough. I've made a couple of ukuleles this way and they sound pretty good, though not so nice as those I make from solid wood.

You can get quite a nice effect by staining birch and then putting a gloss finish over the top. This one uses red ink to get the pink, with Tru Oil as the final finish:



Practice on offcuts to find the colour you like, of course.

With a bowl back you could run lines of purfling between the staves by routing a groove using the corner of a cabinet scraper (steady hand required!). You'd want to scrape these back level, so stain afterwards.

[Bamboori]

So I went to a local hardware store and bought some wood. I'll still have to look in other stores or online for the soundboard (they only had either vinyl or way too thick boards), but I got 5mm pine for the bowl and 10mm mahagoni for the neck/fretboard.
Also I hereby declare my love for mahagoni. The look, the feel, everything about it is great :D

edit: Either I'm not being careful enough or 5mm is a little too thick for bending. Gonna get a planer and make it a bit thinner

[Marty Jacobson]

So I went to a local hardware store and bought some wood. I'll still have to look in other stores or online for the soundboard (they only had either vinyl or way too thick boards), but I got 5mm pine for the bowl and 10mm mahagoni for the neck/fretboard.
Also I hereby declare my love for mahagoni. The look, the feel, everything about it is great :D

edit: Either I'm not being careful enough or 5mm is a little too thick for bending. Gonna get a planer and make it a bit thinner

Yes, 5mm is too thick for bending.. 1.75-2mm will be much easier, while still being plenty strong.
And mahogany is amazing, it is a pleasure to work with and to look at.