Official Luthiers Forum!

Owned and operated by Lance Kragenbrink
It is currently Thu Mar 28, 2024 7:24 am


All times are UTC - 5 hours





Post new topic Reply to topic  [ 8 posts ] 
Author Message
 Post subject: Crack!
PostPosted: Thu Oct 13, 2016 10:37 pm 
Offline
Walnut
Walnut

Joined: Thu Oct 13, 2016 8:18 pm
Posts: 4
First name: Bradford
Last Name: Granath
City: SEATTLE
State: WA
Zip/Postal Code: 98112
Country: United States
Focus: Repair
Status: Amateur
Pix: https://goo.gl/photos/vXazf1Xs2jj5zGq78

I picked this up at the Goodwill for $8. Took off the poly finish and sealer. May have scorched it a little with the heat gun.

What should I do about the crack where the bass wing is splitting away from the guitar?


Top
 Profile  
 
 Post subject: Re: Crack!
PostPosted: Fri Oct 14, 2016 6:36 am 
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
Dan Erlewine of Stew Mac has an excellent book on guitar finishing. In the book he talks about using Bondo for cracks on solid body electrics that will be painted.

The crack should be secured first, likely use epoxy, quality structural epoxy and sound woodworking, gluing, and clamping methods and then fill as necessary and finish.

The book is a good idea though if you're interested in this stuff and Dan's advice is as good as it gets.

Welcome Bradford to the OLF!

_________________
Ann Arbor Guitars


Top
 Profile  
 
 Post subject: Re: Crack!
PostPosted: Fri Oct 14, 2016 1:39 pm 
Offline
Walnut
Walnut

Joined: Thu Oct 13, 2016 8:18 pm
Posts: 4
First name: Bradford
Last Name: Granath
City: SEATTLE
State: WA
Zip/Postal Code: 98112
Country: United States
Focus: Repair
Status: Amateur
Thanks for the book recommend, Hesh. My local library has a copy on the shelf right now so I will certainly pick that up.

I'm worried that the clamping force necessary to close the crack will put too much stress on the rest of the body.



These users thanked the author BradGranath for the post: Hesh (Fri Oct 14, 2016 3:40 pm)
Top
 Profile  
 
 Post subject: Re: Crack!
PostPosted: Fri Oct 14, 2016 3:43 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
BradGranath wrote:
Thanks for the book recommend, Hesh. My local library has a copy on the shelf right now so I will certainly pick that up.

I'm worried that the clamping force necessary to close the crack will put too much stress on the rest of the body.


Got ya, I'd consider filling the crack with structural epoxy and then after that's cured smoothing things out if any remaining cosmetic imperfections exist with bondo. That's what Dan E. describes in his book.

Some cracks even on acoustics if they have been open for a long time should not be forced closed and instead filled usually with wood.

Good call on your part about being concerned about forcing it shut.

_________________
Ann Arbor Guitars


Top
 Profile  
 
 Post subject: Re: Crack!
PostPosted: Fri Oct 14, 2016 10:16 pm 
Offline
Walnut
Walnut

Joined: Thu Oct 13, 2016 8:18 pm
Posts: 4
First name: Bradford
Last Name: Granath
City: SEATTLE
State: WA
Zip/Postal Code: 98112
Country: United States
Focus: Repair
Status: Amateur
I'm thinking I'll steam it lightly, inject a lot of hot hide glue (could inject epoxy, but is it viscous enough to penetrate?), and then clamp as lightly as possible. Clean up. Scrape flat. Is the bondo really necessary? I'm planning on rattlecanning 3 coats of white auto primer, 2 solid color coats, 3 coats of clear, sand, 2 more clear coats with sanding and polishing. With ten coats of paint is anyone gonna notice the lack of bondo?

EDIT: Thumbing through Guitar Player Repair Guide by Mr. Erlewine. This snazzy 3rd edition with DVD the library had has a strat on the cover, but this book does not have any guidance for solidbody electric instrument repair. But it does have a chapter on electronics?? Frustrations aside, this book is fantastic.


Top
 Profile  
 
 Post subject: Re: Crack!
PostPosted: Sat Oct 15, 2016 5:04 am 
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
HHG is only a good choice when the joint is decent, it's not a gap filler. I can't tell from the photo if the crack is open or not.

Bondo is only one possibility if you have imperfections to fill. If not you don't need any filler of course.

I haven't seen the latest edition(s) for ten years now so I can't comment.

_________________
Ann Arbor Guitars


Top
 Profile  
 
 Post subject: Re: Crack!
PostPosted: Sun Oct 16, 2016 8:43 am 
Offline
Contributing Member
Contributing Member

Joined: Sun Feb 17, 2013 4:58 pm
Posts: 1449
First name: Ed
Last Name: Minch
City: Chestertown
State: MD
Zip/Postal Code: 21620
Country: United States
Focus: Build
Status: Amateur
To get the epoxy to penetrate you can do any or all of these things:

Heat the area with a hair dryer
Heat the mixed epoxy with a hair dryer
Use a soda straw directed at the joint to blow the epoxy in
Use a thin piece - think feeler gauge - to slowly work the material down into the joint

The piece is probably now stable after it has cracked, so you are as much filling the crack as gluing it together

Ed


Top
 Profile  
 
 Post subject: Re: Crack!
PostPosted: Mon Oct 17, 2016 1:19 pm 
Offline
Walnut
Walnut

Joined: Thu Oct 13, 2016 8:18 pm
Posts: 4
First name: Bradford
Last Name: Granath
City: SEATTLE
State: WA
Zip/Postal Code: 98112
Country: United States
Focus: Repair
Status: Amateur
Couple of better pictures:
https://goo.gl/photos/vXazf1Xs2jj5zGq78

OK, heat it, heat the epoxy, inject, clamp.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 15 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