Inside mould

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rocket
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Inside mould

Post by rocket » Sun Sep 12, 2021 12:56 pm

Has anyone seen or heard of an inside mould being used on a guitar build? similar to that of violin or double bass moulds.
Most violin makers use the inside mould but i have heard of some using the outside mould.
Pro's that i can think of is no need to for inside bracing/ spreaders and i think the sides might conform to the mould more easily, needing less clamping!
Con's you need to remove the work from the mould before completing the kerning/ lining to one side, so get one plate glued on then remove from mould and then complete linings and close the box.
My small shop is chockers with moulds/forms and bending forms but just considering trying the inside mould on the next build!

Cheers

Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back

www.octiganguitars.com

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sebastiaan56
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Re: Inside mould

Post by sebastiaan56 » Sat Sep 18, 2021 7:46 pm

I’m on fiddle No 9 and have a bit of experience with inside moods now. The biggest issue is spring back. This is resolved by keeping the sides thin, 1.2mm for a fiddle. How that would work for a guitar is a good question.

FWIW French violins, the Mirecourt School, were built with outside molds.
make mine fifths........

TomBeltran
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Re: Inside mould

Post by TomBeltran » Sun Sep 19, 2021 4:01 pm

Ignacio Fleta, who started as a violin builder, used an inside mold to build guitars. There is a video available from Arts On Film, of him building a guitar and it shows his use of an inside mold.

simonm
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Re: Inside mould

Post by simonm » Thu Sep 23, 2021 5:18 am

The StewMac kits used to come with a cardboard inside mould. I did both a D and a Triple O more than a decade ago. Haven't checked if they have changed that. Worked quite well.

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rocket
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Re: Inside mould

Post by rocket » Wed Sep 29, 2021 5:48 pm

Thanks for your thoughts, i don;t intend to duplicate any of my existing moulds but if i decide to do a new model i might go with the inside mould!!

Cheers
Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back

www.octiganguitars.com

johnparchem
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Re: Inside mould

Post by johnparchem » Sun Oct 03, 2021 3:05 am

I have considered using an inside mold for ukuleles but I have never pulled the trigger on my thoughts. I put a pretty good radius on my guitar backs so I have appreciated the support of a mold and spreader as I sand in the radius. I am getting better at cutting my sides close to the finial radiused profile and bending the waist accurately to the cut profile such that I do nut sand very much and might not need the molds support.

I have also found that even with one plate glued on, the spring back in the sides opens the rim a bit. I build my flamencos top down on a work board and find that a mold helps keep the sides square while gluing on the back. In that case I am sure there are other ways to square up the sides with out a full mold.

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