Is this destined to fail?

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Dekka
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Is this destined to fail?

Post by Dekka » Wed May 21, 2014 6:26 pm

I don't get much time to play at this guitar making lark but when life looks the other way for a moment I run down to the shed and dabble as much as I am able.
In doing so, I have been learning from my many mistakes...all except my knack for cracking sides during the bending process. It seems that despite all advice and research it is not one of my strong suits.
This led me to construct sides that didn't need bending and although it has been quite laborious, the result is starting to look good. It is made out of scraps of Fijian Mahogany and Silky Oak. Although the sides are about 7mm thick they are surprisingly light. Adhesive used is Titebond original.
I would appreciate opinions from you guys regarding some of the processes that will follow. For example, when I come to do the Maple binding, I am tending to think that If I attempt a normal routing of the channel the fact that it is all end-grain will result in major tear-out. Should I pre-cut a line with a purfling cutter before routing?
I plan to run a single strip of Mahogany lining along the centre of the rim as extra reinforcement.
Ultimately, this might be a stupid idea but I thought it was worth a try.
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rocket
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Re: Is this destined to fail?

Post by rocket » Wed May 21, 2014 10:57 pm

Dekka, i think you've done a fine job joining all the pieces together to make the body shape but the main problem i can see is the massive amount of expansion and contraction you will have in the sides due to the grain orientation.
Cheers,,

Rod.
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Lutherie Gervais
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Re: Is this destined to fail?

Post by Lutherie Gervais » Thu May 22, 2014 10:25 am

Have you try laminated side ?

I don't work like that, but it is a way.


Good luck with that.

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demonx
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Re: Is this destined to fail?

Post by demonx » Thu May 22, 2014 10:32 am

Now you just need to run some steel bands and fill it with Moonshine!

On a serious note, lots of work there, looks good, but I guess time will tell.

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sebastiaan56
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Re: Is this destined to fail?

Post by sebastiaan56 » Thu May 22, 2014 11:14 am

I dont think you will need extra binding. The sides should route just fine.

One of the violin books recommends using several layers of veneer and laminating them around the mold. An outside mold that is. Also an option.
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Allen
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Re: Is this destined to fail?

Post by Allen » Thu May 22, 2014 11:20 am

I think Rod is correct in that those sides are going to expand / contract with humidity fluctuations far more than you might anticipate. The sides more than likely will survive with all that glue surface, but the top and back are going to get a workout.
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Dekka
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Re: Is this destined to fail?

Post by Dekka » Thu May 22, 2014 12:14 pm

I have a top and back that are fairly seriously domed (1m radius). I'm hoping there might be enough give in it to cope. I am also going to make a height-adjustable floating bridge to compensate.
Am I likely to get RH expansion/contraction if it is sealed completely?

PS Thanks for the advice.
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Allen
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Re: Is this destined to fail?

Post by Allen » Thu May 22, 2014 12:23 pm

A very domed back and front may just be what the doctor ordered.

Sealing both surfaces will buffer fluctuations in humidity, but will not eliminate the effects. If it's overly humid or dry, wood is still going to loose or pick up moisture. Just not so quickly.
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tippie53
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Re: Is this destined to fail?

Post by tippie53 » Mon Jun 02, 2014 12:46 am

this is going to be tough, the expansion rate , the weight. You would be better off to veneer this. As the top and back contract and expand you will see your sides fail. Hate to be the bearer of bad news. The top and back will expand across the grain, in typical guitars the grain on the sides is opposite of this will can take the stress and wood can take a good bit of tension with the grain but when you put that stress across the grain it will fail and crack.
Veneer will just be a cover on a main strata and will give you the same effect and take the stress loads . Also the weight will be an issue.
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