Official Luthiers Forum!

Owned and operated by Lance Kragenbrink
It is currently Thu Mar 28, 2024 5:12 pm


All times are UTC - 5 hours





Post new topic Reply to topic  [ 9 posts ] 
Author Message
PostPosted: Tue Apr 23, 2019 12:23 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Mon Aug 23, 2010 11:42 pm
Posts: 1701
First name: John
Last Name: Parchem
City: Seattle
State: Wa
Zip/Postal Code: 98177
Country: USA
Focus: Build
Status: Amateur
A friend of mine (a professional bass player) tripped over his knock around guitar and cracked the neck right off. I do not think these are worth a fortune but he did like the guitar. When I looked at it, I though I could quickly get it in playable condition but I thought I would run my plan by you guys to set me straight. He does know that the repair will be visible.

Although it looks bad, I have the pieces and can put them back together and keep the neck alignment in place. Looking at his saddle perhaps improve it.

Image

Image

My thought is to clean up the old glue on the poor glue job on the neck block extension, I can tell only part of it was joined, and reglue it and the broken heal block with a structural epoxy. I would use fish glue or titebond hide glue to put the top back together. I thought of using hot hide glue but I really want the open time to get every into position as it is a 3D puzzle piece to fit in. Both the fish glue and the titebond hide glue are cleanable.

Once in and clamped (no glue yet) It looks like I can do a reasonable job of keeping things in alignment with the same neck angle.

Image

Image

Image

Image

_________________
http://www.Harvestmoonguitars.com


Top
 Profile  
 
PostPosted: Wed Apr 24, 2019 6:40 am 
Offline
Brazilian Rosewood
Brazilian Rosewood
User avatar

Joined: Mon Dec 27, 2010 9:06 pm
Posts: 2739
Location: Magnolia DE
First name: Brian
Last Name: Howard
City: Magnolia
State: Delaware
Zip/Postal Code: 19962
Country: United States
Focus: Repair
Status: Professional
Lots of long grain to glue on the top, that's good. The head block and heel will be the trouble spot and as you can see 70% of the original glue did nothing in that area. I might opt for some small dowels in there to hold it together.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/


Top
 Profile  
 
PostPosted: Thu Apr 25, 2019 11:26 am 
Offline
Cocobolo
Cocobolo

Joined: Thu Oct 27, 2011 11:28 am
Posts: 183
First name: Leonard
Last Name: Duke
City: Kalamazoo
State: MI
Zip/Postal Code: 49001
Country: USA
Focus: Repair
Status: Amateur
When it came time to glue it I would have my clamping cauls made so that I could put on the two outside strings and tighten them just enough to be straight. The cauls can poush down in the middle of the fretboard between the two strings. I don't want that glue to set up unless I am positive that the neck alignment is perfect: side to side and neck tilt both. Looking at how the two strings align on the neck and the action height would tell me if I needed to loosen the clamps a bit, shove the neck into better alignment and retighten the clamps.

After that first glueing dried I would glue in many light spruce splints with their grains going across the separations. Other spruce triangles could be glued in at the corners. If I make it a little stronger than when it was new, without adding much weight, it won't be coming back to me to fix again.


Top
 Profile  
 
PostPosted: Thu Apr 25, 2019 1:08 pm 
Offline
Brazilian Rosewood
Brazilian Rosewood

Joined: Fri Aug 19, 2005 4:02 am
Posts: 3227
Location: The Woodlands, Texas
First name: Barry
Last Name: Daniels
Fish glue would give you the longest open time. The long grain of the breaks will certainly be to your advantage. But getting all the joints to close will be a challenge. Will be interesting to see how this one turns out.


Top
 Profile  
 
PostPosted: Thu Apr 25, 2019 6:56 pm 
Offline
Old Growth Brazilian Rosewood
Old Growth Brazilian Rosewood
User avatar

Joined: Fri Nov 02, 2007 9:49 am
Posts: 12971
Location: Ann Arbor, Michigan
First name: Hesh
Last Name: Breakstone
City: Ann Arbor
State: Michigan
Country: United States
Status: Professional
I didn't read any of the posts but wanted to point out that there is no saddle left AND someone has already filed in string ramps. As such this thing has a poor neck angle (before it broke) and likely will have the same poor neck angle when pieced back together if a neck reset is not done.

_________________
Ann Arbor Guitars


Top
 Profile  
 
PostPosted: Thu Apr 25, 2019 7:47 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Wed Nov 12, 2014 10:02 am
Posts: 513
First name: Daniel
Last Name: Petrzelka
State: Washington
Country: United States
Focus: Build
I would be tempted to separate the neck and heel from the body and top piece - this would allow for easier handling when gluing the body back together, and set you up for doing the neck reset that, as Hesh pointed out, likely needs to be done.

Separating the neck will also ensure you are not fighting the weight of the neck when glueing that top/body piece back on. You can really take care to align the grain and get a good clean glue-up.



These users thanked the author dpetrzelka for the post: Barry Daniels (Thu Apr 25, 2019 8:21 pm)
Top
 Profile  
 
PostPosted: Thu Apr 25, 2019 8:22 pm 
Offline
Brazilian Rosewood
Brazilian Rosewood

Joined: Fri Aug 19, 2005 4:02 am
Posts: 3227
Location: The Woodlands, Texas
First name: Barry
Last Name: Daniels
That is a good idea, Daniel.


Top
 Profile  
 
PostPosted: Fri Apr 26, 2019 1:09 am 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Mon Aug 23, 2010 11:42 pm
Posts: 1701
First name: John
Last Name: Parchem
City: Seattle
State: Wa
Zip/Postal Code: 98177
Country: USA
Focus: Build
Status: Amateur
Thanks all, for the suggestions. I decided against a few of the options because I just could not put the time in it. I found nice used versions of this guitar for about $500. I did decide that I was not going to give it back without a decent bit of saddle showing at a good action. I kept with my decision to use structural epoxy for the neck block and I used titebond hide glue for all of the non structural work. Both gave me a decent amount of working time to get things right. I mocked all of the clamps and played until I was able to have a straight edge from the first fret to the current short saddle with an action of about 1 mm. I use the first fret instead of the nut as it results in an action that is closer to the result when strung up. Anyway my reasoning was that going from 1 mm to 2.5 mm of action would add 3 mm to the saddle. Part of the damage when the neck broke off was a missing wedge of mahogany just at the transition to the heel. That missing piece was enough that even when all clamped up the weight of the head stock and tuners pulled the neck back a touch and gave me the exact neck angle I wanted. Here is the saddle with 2.5 mm action for the low e. The E string is 12.5 mm off the top. The action could be lowered to 2 mm if he wants.

Image

To illustrate, I actually switched to a straight edge when I checked it for the real glue up.

Image

Image


Here is where the wood was missing I already filled it with a mahogany patch and have started finish repair

Image


I never promised an invisible repair, the guitar has plenty of scratches and pick gouges so it was not too hard to do a repair that sort of blended in. Well at least the guitar really plays well.

Image

Image

Image

Image

_________________
http://www.Harvestmoonguitars.com


Top
 Profile  
 
PostPosted: Fri Apr 26, 2019 7:46 am 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Wed Oct 08, 2008 11:36 am
Posts: 7241
Location: Southeast US
City: Lenoir City
State: TN
Zip/Postal Code: 37772
Country: US
Focus: Repair
Nice work. Always feels good to take a broken instrument and turn it back into a player.

_________________
Steve Smith
"Music is what feelings sound like"


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 11 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group
phpBB customization services by 2by2host.com