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Beginning builder here. This morning, I used a smooth plane to hand thickness two strips of Indian Rosewood for the back of a guitar. The plane was shaving so beautifully, I fell into a trance and stupidly shaved one of the sides down to 2 mm thick. The plans I'm using call for 2.4 mm. So my question is this: Is 2 mm too thin for a guitar back made of Indian Rosewood? Should I just scrap the wood and thickness a new back, or will 2 mm be strong enough? Any advice would be greatly appreciated. Thanks. -Sam

This is pretty thin. What kind of wood is it?

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

It's Indian Rosewood. It will be for a dreadnought style guitar. -Sam

the difference between 2mm and 2.4 mm isnt much. if this is your first guitar id say go forward and brace accordingly.

in reading your post, its sounds like you havent joined the two back halves yet. if this is the case, its going to take some very careful joining to minimize cleanup afterwards. otherwise, you may well be too thin after you get everything level.

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sweat the small stuff.

You're fine. Truck on.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Have you already jointed up the back?

If not, get to jointing now before things are too thin... Those glue joints don't always line up perfectly, so you will probably have some plane work cleaning up the misalignment...

Then you will be levelling -- sanding out all the lumps, bumps, and chips... Maybe stop while you are ahead.

Thanks

John

2 mm is .074 , that is pretty thin for a dred back. ,090 is as far as I would go. If the back is not joined you are going to be even thinner . there can be some examples that you may get away with it. How well quartered is the wood? Any flaw in it will be maginifed the thinner you go.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

How thin can a guitar back be, a guitar back can be as thin as a guitar back could be. Sorry, couldn't help myself (wood chuck thing).

Might want to think about heavier bracing or even a Spanish foot on your head block.
Clinton

Ya, so she a bit thin...pay attention to gluing the plates together. May be on a ply carrier and go bars to make sure the edges line up as flat as possible...go a little thicker on yer braceing and enjoy the bass//bottom end she gonna have.

icu
Duh
Padma

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Sam: What are you using to take your measurments....? Two m.m. is almost .079 and if you do a perfect join and need very little clean up you'll be OK. Also are you 2m.m. all over or just in a small area...?
Tom

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A person who has never made a mistake has never made anything!!!

2 mm sounds pretty thin to me too although I agree that it could be done. I generally join plates in the .140ish area and like John for a dread I will thin to .090 for final thickness.

Thanks, everyone. I think I'm going to play it safe and thickness a second set of back plates. It sounds like I won't have much leeway if I try to join at 2mm, so I figure I'll save the 2mm pieces and join them later -- once I've done it once or twice and have a litter more confidence in my back-joining skills. All of your advice has been really helpful. Thanks. -Sam

That might also allow you to save the thin set for a smaller guitar, which might make it less critical.

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Dave
Milton, ON

Maybe glue then thickness the wood?

You could add an extra brace,like 5 instead of 4. If the back is too thin,you will hear it in the tone later.

I'm with George on the extra brace. Use 5 instead of four and put the extra one in the lower bout to stiffen it.
This is exactly what I once did to utilize a very nice piece of Brazilian rosewood that had been thinned out a bit much.

would it work to do a very thin veneer on what will be the inside? Gives you that extra bit of mass/thickness you need for strength and a little room for over sanding after joining. Kind of like a double top, without anything sandwiched in between the layers.

-Matthew

Relax, you now have enough peghead veneer for your next 15 builds. Ask me how I know....

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In Markham,Virginia

Or save it for a 12" parlor.