12 String SS Falcate braced Ziricote\spruce guitar.

Show us how your current project is progressing
Post Reply
John Parchem
Posts: 2678
Joined: Fri Dec 23, 2011 8:33 pm
Location: Seattle
Contact:

12 String SS Falcate braced Ziricote\spruce guitar.

Post by John Parchem » Sat Apr 02, 2016 7:22 pm

A player I know asked me to build him a 12 string guitar. He really likes the Gore medium body Steel String I built. He likes the size, shape and the sound. This lead me to start a 12 string falcate braced guitar. The 12 string presents a number of issues including how to modify the braces to support the increased string load and a 12 pin bridge would not work with the falcate bracing pattern I use.

After asking for some suggestions on the Australian/New Zealand Luthiers Forum (the home of many Gore followers) a member (woodsy23) modified an existing Finite Element (FE) model he had for 12 strings load, both light and medium (EJ38s and EJ39s). He determined I would need to increase the height of the falcate braces from 7 mm to 10 mm for the EJ38s and 11 mm for the EJ39s. I will probably stick with 10 mm as I want to limit the monopole frequency of the top to keep it in the typical SS range.

Also from the anzlf I found a tutorial for making a 6 pin 12 string bridge by Craig Lawrence. Way cool!

Image

I had been thinking of going pinless but the above bridge looked pretty cool.

My client selected a nice looking set of Zicicote. The wood is pretty, has a nice tap tone but it is very dense. Not as dense as Cocobolo but denser than EIW ro BRW. This choice may push me away from an active back as it is a lot of mass to get moving. Also the wood is supposedly real brittle and hard to bend.

Image

Before going any farther I decided I was first going to see if I could bend the tight Venetian cut away this the guitar design has. To increase my chances I decided to use almost all the tricks to bend brittle wood.

The first was a new suggestion from some forum. Wash one side of teach side with naptha; turn the board over and mark where the naptha comes through. This seems to be a brilliant idea as it will highlight any existing cracks. Then on wax paper flood the marked areas with thin CA.

Image

Image

Image

The sides were thinned to about 2 mm or .080" and then starting a bit above the waist I used a scraper to take the area in the Venetian cutaway to .070"

Image

I spritzed the sides with super soft II and let them sit over night.

Image

while warming the sides in my fox style bender to about 300 degrees I used a heat gun to warm the inside of the Venetian cutaway.

Image

After all of that the bending was uneventful and I had very little spring back. In the last picture you can see it in the mold with no clamps.

Image

Image

Image

Image

Now I am just waiting for the regular side to cool and set.

Image

Dave Bagwill
Posts: 5949
Joined: Tue Dec 13, 2011 7:44 pm

Re: 12 String SS Falcate braced Ziricote\spruce guitar.

Post by Dave Bagwill » Sat Apr 02, 2016 8:18 pm

I'm glad it worked out for you John. Ziri scared me enough that I laminated the sides - 2 x .040". Even then I held my breath. Figuratively.
-Under permanent construction

Tim Benware
Posts: 1489
Joined: Thu Dec 22, 2011 1:22 pm
Location: Asheboro, NC

Re: 12 String SS Falcate braced Ziricote\spruce guitar.

Post by Tim Benware » Sun Apr 03, 2016 9:01 am

I like that 6 pin, 12 string bridge. Does it use unslotted pins with 2 slots cut in the holes?
I've "Ben-Had" again!
Tim Benware
Creedmoor, NC

John Parchem
Posts: 2678
Joined: Fri Dec 23, 2011 8:33 pm
Location: Seattle
Contact:

Re: 12 String SS Falcate braced Ziricote\spruce guitar.

Post by John Parchem » Sun Apr 03, 2016 9:29 am

Tim Benware wrote:I like that 6 pin, 12 string bridge. Does it use unslotted pins with 2 slots cut in the holes?
Yes, unslotted pins with 2 slots in the holes.

Tim Benware
Posts: 1489
Joined: Thu Dec 22, 2011 1:22 pm
Location: Asheboro, NC

Re: 12 String SS Falcate braced Ziricote\spruce guitar.

Post by Tim Benware » Sun Apr 03, 2016 4:27 pm

johnparchem wrote:
Tim Benware wrote:I like that 6 pin, 12 string bridge. Does it use unslotted pins with 2 slots cut in the holes?
Yes, unslotted pins with 2 slots in the holes.
I like it!
I've "Ben-Had" again!
Tim Benware
Creedmoor, NC

dave d
Posts: 451
Joined: Sun Jan 01, 2012 11:05 pm
Location: Toronto-ish

Re: 12 String SS Falcate braced Ziricote\spruce guitar.

Post by dave d » Sun Apr 03, 2016 4:38 pm

Very exciting for me to watch, as I'd love to build a 12 string someday. I really like that bridge too! Thanks for the great pics and fantastic explanations of the process as always John.

ken cierp
Posts: 3924
Joined: Tue Dec 13, 2011 11:23 pm

Re: 12 String SS Falcate braced Ziricote\spruce guitar.

Post by ken cierp » Sun Apr 03, 2016 4:45 pm

I like that too -- I've been think about producing a 12 string kit -- I'd like to see the video regarding that bridge.

Post Reply