My Second Build

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DavidS
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My Second Build

Post by DavidS » Wed Oct 16, 2019 4:44 pm

I have been working on my second guitar build. It is medium sized falcate braced steel string as per the book but I am not attempting a cut away.
Image
I glued the back on today.
Image
It is Camphor Laurel with Silver Ash bracing & linings. Uncoupled resonance is looks like 211Hz which seems OK. I am targeting 214Hz. There is a weaker peak at 150Hz, not sure what that is?

DavidS
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Re: My Second Build

Post by DavidS » Tue Oct 22, 2019 1:50 pm

Here are pictures that I tried to attach to previous post:
IMG_20191016_160909.jpg
IMG_20191016_160647.jpg

I have now glued on the soundboard:
IMG_20191021_082543.jpg
I have tap tested the body. I am targeting:
T(1,1)1 90Hz
T(1,1)2 170Hz
T(1,1)3 214Hz

I currently 97Hz, 180Hz, 215Hz with the bridge pins taped over. A little bit concerning is that when I apply 20 grams of blue tack and timber blocks on the bridge position, I get 96,170,213.

I suppose I cannot thin the soundboard edge and will need to keep the bridge very light. My concern is how the application of finish (French Polish) will effect the T(1,1)2 as it's already right on target. Hopefully the stiffness added when the bridge is glued on will give me a little breathing space.

Advice welcome.

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lamanoditrento
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Re: My Second Build

Post by lamanoditrento » Tue Oct 22, 2019 2:14 pm

Nice clean work there. You have to put some finish on and fp is normally thinner than most. Also things change a bit with binding and the neck attached so you may wanna hold one change too much just yet
Trent

DavidS
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Re: My Second Build

Post by DavidS » Tue Oct 22, 2019 8:09 pm

Hi Trent, thanks for your reply. "Clean Work" is a very much appreciated compliment for me.

I am trying to figure out whether I am going to be able to achieve a finished T(1,1)2 close enough to 170Hz given I am starting at 180hz closed box. I simply don't know how much effect binding, neck, finish, bridge & strings are going to have. Unfortunately I did not pay attention to this on my first build. Do I have a reasonable chance of making it work or should look at a new soundboard?

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Trevor Gore
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Re: My Second Build

Post by Trevor Gore » Wed Oct 23, 2019 8:22 am

DavidS wrote:
Tue Oct 22, 2019 8:09 pm
I am trying to figure out whether I am going to be able to achieve a finished T(1,1)2 close enough to 170Hz given I am starting at 180hz closed box.
Provided you remove very little wood on binding and clean-up and use a very low mass bridge (< 15 gms), you should be close.

seeaxe
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Re: My Second Build

Post by seeaxe » Wed Oct 23, 2019 4:46 pm

Can't comment on the numbers but that back and those sides are stunning. Going look a million dollars when it's finished. Good luck with your build.
Richard

DavidS
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Re: My Second Build

Post by DavidS » Wed Oct 23, 2019 9:41 pm

Thanks Trevor, Thanks Richard, I will carry on and see where it ends up. Started making the bridge today. Padauk with CF. Will be interesting to see if 15g can be achieved.

David

DavidS
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Re: My Second Build

Post by DavidS » Mon Oct 28, 2019 8:51 am

I finished bridge and managed to get to 17g. To get down to that, I needed to reduce the footprint a little. It is about 41.5 cm2 which is lower than the book recommendation. I am hoping that's OK given that I have at stiff bridge plate with carbon fibre.
IMG_20191026_172407.jpg
I improved my tapping technique using a pencil eraser and my closed box T(1,1,)2 is 185Hz, a little higher than the 180 I was getting previously. With the bridge attached using really good thin double sided tape I get 182Hz. So, I'm looking comfortable for my 170Hz target. Just wondering if a little bit of edge thinning is advisable?

Dave M
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Re: My Second Build

Post by Dave M » Tue Oct 29, 2019 8:59 am

David that top bracing is incredibly clean. I know just how hard it is not spray epoxy all over the place. Also that Laurel looks rather fine.

Doing cutaways seriously adds to the difficulties but I have decided that the advantage to the player means I should pretty much always do one. Having built a side bender that is fairly reliable for cutaways makes life easier.

I am however impressed with your bridge weight. I really struggle with rosewood to get it down to the level I would like. Have you thinned it down significantly?
------------------
Dave

DavidS
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Re: My Second Build

Post by DavidS » Tue Oct 29, 2019 2:53 pm

Hi Dave, thanks for your comments. I am working up to doing a cutaway, perhaps next time.

Bridge is 9mm high at the centre of the front. I have raduised the saddle area to about 20" so it is not as high at the ends of the saddle. At the back it is about 7mm high. The back face is chamfered at about 15deg. Wings about 1.8mm high. Width 34.5 Max and length 151mm Max.

Just hope it has enough glueing area.


David

DavidS
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Re: My Second Build

Post by DavidS » Sat Nov 02, 2019 11:25 am

I am open for advice on my bridge glueing area of 41.5mm2. I am considering making a bigger bridge. Currently have a top resonance of 182Hz with bridge taped on. Target is 170Hz so I could accommodate a heavier bridge.

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Trevor Gore
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Re: My Second Build

Post by Trevor Gore » Sun Nov 03, 2019 10:03 am

Your bridge looks the same size as mine (presumably made off the book drawings). Mine stay on! Them peeling off is as much about the bridge plate design as it is about the glue area, and you have the standard falcate bridge plate.

DavidS
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Re: My Second Build

Post by DavidS » Sun Nov 03, 2019 4:14 pm

Thanks Trevor. I started with the book dimensions but did take a bit of to get the weight down. I thought it was more but when I look closely it was only 1.5mm off the back and 2mm off each end. That should be within the safety margin.
Regards
David

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