Official Luthiers Forum!

Owned and operated by Lance Kragenbrink
It is currently Thu Mar 28, 2024 3:44 pm


All times are UTC - 5 hours





Post new topic Reply to topic  [ 23 posts ] 
Author Message
PostPosted: Sat Jun 27, 2015 6:53 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Fri May 18, 2012 8:35 pm
Posts: 2658
Location: Austin, Texas
First name: Dan
Last Name: Smith
City: Round Rock
State: TX
Zip/Postal Code: 78681
Country: USA
Focus: Build
Status: Amateur
Once again I ended up with a visible seam on the top.
I made a very good joint and glued the seam with epoxy using a good amount of clamping pressure.
I glued the top to the body using Titebond.
I suspect the Titebond swelled the wood and then the wood shrunk while drying.
Any suggestions for the next one?
I thought of using a slow set epoxy rather than a water based glue.
I'll leave this one as-is, I think any attempt to cover it will not look good.
Thanks,
Dan


You do not have the required permissions to view the files attached to this post.

_________________
wah
Wah-wah-wah-wah
Wah


Top
 Profile  
 
PostPosted: Sat Jun 27, 2015 7:18 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Sat Feb 02, 2008 4:01 pm
Posts: 1104
Location: Winfield, IL.
Had a friend with the same problem. His was caused by a dirty plane sole which didn't look at all dirty. Cleaning it with lacquer thinner revealed the problem. Hope your issue is as easy to solve.

Steve



These users thanked the author StevenWheeler for the post: dzsmith (Sat Jun 27, 2015 7:32 pm)
Top
 Profile  
 
PostPosted: Sun Jun 28, 2015 7:12 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
I suspect your joint was not as nice as you thought. It appears to be fairly tight at the ends with more of a gap in the middle. This was not caused by either of the glues simply looks like a joint that could have been fit better.

_________________
Brian

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

https://www.howardguitarsdelaware.com/



These users thanked the author B. Howard for the post: dzsmith (Sun Jun 28, 2015 10:21 am)
Top
 Profile  
 
PostPosted: Thu Jul 02, 2015 8:17 am 
Offline
Cocobolo
Cocobolo
User avatar

Joined: Tue Feb 26, 2013 9:41 am
Posts: 150
First name: Matt
Last Name: Cushman
City: Great Falls
State: MT
Zip/Postal Code: 59401
Country: usa
Focus: Build
Status: Professional
The only upside is, some of the joint will be hidden under the neck ,bridge, pups, strings and a pick guard, if you use one. It looks like the joint is ok behind the bridge.

_________________
http://www.cushmanguitars.com/.

A man who carries a cat by the tail learns something he can learn in no other way.
Mark Twain


Top
 Profile  
 
PostPosted: Thu Jul 02, 2015 9:40 am 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Fri May 18, 2012 8:35 pm
Posts: 2658
Location: Austin, Texas
First name: Dan
Last Name: Smith
City: Round Rock
State: TX
Zip/Postal Code: 78681
Country: USA
Focus: Build
Status: Amateur
Yeah,
It should look fine.

_________________
wah
Wah-wah-wah-wah
Wah


Top
 Profile  
 
PostPosted: Thu Jul 02, 2015 11:36 am 
Offline
Brazilian Rosewood
Brazilian Rosewood

Joined: Thu Nov 04, 2010 1:46 pm
Posts: 2124
First name: Freeman
Last Name: Keller
Focus: Build
Status: Amateur
I've always had trouble "shooting" that joint so the last few I've simply clamped the two pieces together and clamped a very straight piece of aluminum flat stock to them (you could use a straight level). I've just run the router with a flush cut bit and the joints have been darn near perfect. You might want to practice on some scrap but at least for now that's the way I'll be doing it.


Top
 Profile  
 
PostPosted: Thu Jul 02, 2015 12:17 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Fri May 18, 2012 8:35 pm
Posts: 2658
Location: Austin, Texas
First name: Dan
Last Name: Smith
City: Round Rock
State: TX
Zip/Postal Code: 78681
Country: USA
Focus: Build
Status: Amateur
Good idea!
Thanks Freeman.
Dan

_________________
wah
Wah-wah-wah-wah
Wah


Top
 Profile  
 
PostPosted: Thu Jul 02, 2015 12:25 pm 
Offline
Brazilian Rosewood
Brazilian Rosewood

Joined: Wed Apr 08, 2009 9:34 am
Posts: 3081
I'm assuming the maple top is around 3/8" when I say that it is a lot harder to make a good joint than with a 3/16" top. Archtop guitars and mandolins are even worse with 3/4-7/8" thick tops and backs.



These users thanked the author Haans for the post: dzsmith (Thu Jul 02, 2015 1:37 pm)
Top
 Profile  
 
PostPosted: Thu Jul 02, 2015 12:27 pm 
Offline
Brazilian Rosewood
Brazilian Rosewood

Joined: Wed Apr 08, 2009 9:34 am
Posts: 3081
OOPS, DOUBLE POST!


Top
 Profile  
 
PostPosted: Fri Jul 03, 2015 10:49 am 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Fri May 18, 2012 8:35 pm
Posts: 2658
Location: Austin, Texas
First name: Dan
Last Name: Smith
City: Round Rock
State: TX
Zip/Postal Code: 78681
Country: USA
Focus: Build
Status: Amateur
The seam is definately a poor joint.
I have a good technical knowledge of guitar making, but my woodworking skills are not so great.
I'm trying to use mainly hand cutting tools, but I need to rethink and use whatever tools will produce the best results.
Thanks for the feedback, you fellows are the best!
Dan

_________________
wah
Wah-wah-wah-wah
Wah


Top
 Profile  
 
PostPosted: Sat Jul 04, 2015 9:45 am 
Offline
Koa
Koa

Joined: Sat May 17, 2014 12:45 pm
Posts: 644
First name: Lonnie
Last Name: Barber
City: Manchester
State: Tennessee
Zip/Postal Code: 37355
Country: United States
Focus: Build
Status: Amateur
Seams sometimes are hard to come by. Nice ones anyway. Practice helps


Sent from my iPhone using Tapatalk


Top
 Profile  
 
PostPosted: Sat Jul 04, 2015 6:45 pm 
Offline
Brazilian Rosewood
Brazilian Rosewood
User avatar

Joined: Sat May 22, 2010 10:32 am
Posts: 2616
First name: alan
Last Name: stassforth
City: Santa Rosa
State: ca
Zip/Postal Code: 95404
Country: usa
Focus: Build
Status: Amateur
I use sandpaper glued to an aluminum straightedge,1" x 2",
put a 1/4" piece of something under the top,
and carefully sand away,
checking the joint with light behind it.
The sun works well for the light source!
After you put all the pickups, bridge, and whatever else,
nobody but you, or another luthier will notice.
Alan



These users thanked the author alan stassforth for the post: dzsmith (Sat Jul 04, 2015 10:21 pm)
Top
 Profile  
 
PostPosted: Tue Nov 10, 2015 10:43 pm 
Offline
Mahogany
Mahogany
User avatar

Joined: Thu Apr 19, 2012 10:02 am
Posts: 92
City: Alton
State: IL
Focus: Build
Status: Amateur
Did you use a shooting board? If so, and you want to continue to use this method, shoot them together, one on top of the other with the top of each facing inward. A slight angle will show up as a visible glue line if you do them separate, but if you do it this way any angles created will be supplementary angles, so you'll get a nice joint.

Brian mentioned above it looks like the top and bottom are fine, but the middle is there is a gap. Which should be theoretically impossible with a shooting boards. Some people construct their boards at a angle to the plane, like the link below. This is done so that you aren't just using a small portion of the plane iron, and you have even ware on the plane. If you are shooting, and you are using that style of a board, then it's possible it's cause by plane setup.

Also, I like Freeman's idea. I may give that a shot.
http://www.breseplane.com/olive1.jpg


Top
 Profile  
 
PostPosted: Sun Nov 15, 2015 9:47 am 
Offline
Koa
Koa

Joined: Tue Jan 22, 2008 8:57 pm
Posts: 735
Location: Austin, Texas
Freeman wrote:
I've always had trouble "shooting" that joint so the last few I've simply clamped the two pieces together and clamped a very straight piece of aluminum flat stock to them (you could use a straight level). I've just run the router with a flush cut bit and the joints have been darn near perfect. You might want to practice on some scrap but at least for now that's the way I'll be doing it.


I do this type of thing all the time...

though I use a top bearing flush cut bit (read as pattern bit) and always climb cut first then go back again traditionally cutting to clean things up...one very big concern is that the router bit must be perfectly square to the base...this problem can be mitigated by doing what has already been suggest...clamp the 2 pieces together (assuming your bit is long enough to trim both at once) in a bookmatched fashion (e.g. to be seen faces touching) as this will result in any angle off of square to be reflexive (read that as when pieces are oriented to be joined and doing so any error will still result in a flat glue up)


Top
 Profile  
 
PostPosted: Sun Nov 15, 2015 10:18 am 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Fri May 18, 2012 8:35 pm
Posts: 2658
Location: Austin, Texas
First name: Dan
Last Name: Smith
City: Round Rock
State: TX
Zip/Postal Code: 78681
Country: USA
Focus: Build
Status: Amateur
Well, I'm pretty sure the gap was caused by humidity changes.
The gap is no longer visible at normal humidity levels.
I'm working on a hollow body and have really noticed wood movement.
I cannot afford to control my garage environment.
We had 30 straight days of rain, then 30 straight days of drought.
Now the humidity levels are around 50%.
This was a good learning experience for me.
Thanks,
Dan

_________________
wah
Wah-wah-wah-wah
Wah


Top
 Profile  
 
PostPosted: Tue Nov 17, 2015 9:40 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Fri Aug 26, 2011 2:21 am
Posts: 668
Location: Philadelphia
First name: Michael
Last Name: Shaw
City: Philadelphia
State: PA
Zip/Postal Code: 19125
Country: USA
Focus: Repair
Status: Semi-pro
Can I ask why you used epoxy for the bookmatching.

Sent from my SGH-T599 using Tapatalk

_________________
Another day, another dollar.


Top
 Profile  
 
PostPosted: Tue Nov 17, 2015 10:11 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Fri May 18, 2012 8:35 pm
Posts: 2658
Location: Austin, Texas
First name: Dan
Last Name: Smith
City: Round Rock
State: TX
Zip/Postal Code: 78681
Country: USA
Focus: Build
Status: Amateur
Shaw wrote:
Can I ask why you used epoxy for the bookmatching.

Sent from my SGH-T599 using Tapatalk

Michael,
My reasoning was to water-proof the joint.
I applied a water based dye to the top and I was worried about water softening the joint.
Also, if I ended up with a gap, I would be able to sand the epoxy better than I could sand Titebond.
I'm gluing tops with slow-set epoxy these days. I've had veneers and 1/4" tops crack while drying using Titebond, probably because of the wood shrinking, and from applying too much clamping pressure not allowing it to move. Also, the epoxy has a much longer working time to spread out an even coat.

I still use Titebond for everything else.
Dan


You do not have the required permissions to view the files attached to this post.

_________________
wah
Wah-wah-wah-wah
Wah


Top
 Profile  
 
PostPosted: Tue Nov 17, 2015 11:11 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Fri Aug 26, 2011 2:21 am
Posts: 668
Location: Philadelphia
First name: Michael
Last Name: Shaw
City: Philadelphia
State: PA
Zip/Postal Code: 19125
Country: USA
Focus: Repair
Status: Semi-pro
Okay I have never experienced problems with titebond on tops. But then again I don't use waterbased dyes. I wouldn't have thought it would have an effect like that.

Sent from my SGH-T599 using Tapatalk

_________________
Another day, another dollar.


Top
 Profile  
 
PostPosted: Wed Nov 18, 2015 5:51 am 
Offline
Cocobolo
Cocobolo

Joined: Thu Feb 09, 2012 4:10 pm
Posts: 272
First name: Chris
Last Name: Reed
City: Stowmarket
State: Suffolk
Zip/Postal Code: IP14 2EX
Country: UK
Focus: Build
Status: Amateur
I had a problem which *looks* similar when joining an acoustic back with Titebond. After a couple of days the edges of the seam curled up and out slightly, leaving me with small ridges with a dip in between. Unfortunately this was on the face side, which I'd lined up so well that I hadn't had to take it down in any significant way (on the inside I'd removed material to achieve final thickness, and the joint was fine on that side). My guess is that the swelling and shrinking during glueing produced this effect, and if only I'd left the thicknessing another couple of days I could have removed the offending parts. Maybe in your case enough moisture seeped through from the Titebond to produce the same effect? If so, I think the answer is to leave a little extra wood on and then remove it once the joint has fully cured.

If it's a poor-fitting joint, you might try the technique of a friend of mine (though we both make ukes, which are much smaller - this might not work for guitars). He simply clamps his jointer plane upside down in a vice, holds the plates together, and then passes them along the plane. I tried that recently and got a very well-fitting joint with far less effort than normal.



These users thanked the author profchris for the post: dzsmith (Wed Nov 18, 2015 9:53 am)
Top
 Profile  
 
PostPosted: Sat Nov 21, 2015 6:57 am 
Offline
Walnut
Walnut

Joined: Fri Nov 20, 2015 7:18 am
Posts: 17
Location: Midlands UK
Status: Amateur
alan stassforth wrote:
I use sandpaper glued to an aluminum straightedge,1" x 2",
put a 1/4" piece of something under the top,
and carefully sand away,
checking the joint with light behind it.
The sun works well for the light source!
After you put all the pickups, bridge, and whatever else,
nobody but you, or another luthier will notice.
Alan




Very true! It will also melt the cells in your macula very efficiently unfortunately. Not a good idea for the long term performance of your eyes even with quality sun specs on!


Top
 Profile  
 
PostPosted: Sun Nov 22, 2015 2:16 am 
Offline
Brazilian Rosewood
Brazilian Rosewood
User avatar

Joined: Fri Jan 15, 2010 3:34 pm
Posts: 2047
First name: Stuart
Last Name: Gort
Country: USA
Focus: Build
Status: Semi-pro
Epoxy is aggressive and WILL seep into Maple. Maple is actually fairly porous. I use epoxy for everything EXCEPT panel edge gluing on light colored facings. For that I use Tightbond.

Still....I suspect it's the edge joining rather than having used epoxy that is causing your problem.

I use a cnc machine to provide a perfect edge to my plates. I also made a gluing jig that provides a LOT of edge pressure when gluing. This always creates a fantastic seam.

Although it's harder with more conventional tools....I can say with certainty that the better you join those edges...and the more pressure you use when gluing....the better the result.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic


Top
 Profile  
 
PostPosted: Sun Nov 22, 2015 10:24 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 we see a lot of small Luthier built instruments and when I can see a center seam it's often because the maker used sand paper to refine the joint. The contamination from the abrasives if not totally removed can darken a joint enough to make it show.

Rule one in our shop for repairing cracks to be invisible is to wash our hands because even the dirt on our fingers likes to go on the move once we are poking and prodding with wet glue.

_________________
Ann Arbor Guitars


Top
 Profile  
 
PostPosted: Sun Nov 22, 2015 10:47 am 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Fri May 18, 2012 8:35 pm
Posts: 2658
Location: Austin, Texas
First name: Dan
Last Name: Smith
City: Round Rock
State: TX
Zip/Postal Code: 78681
Country: USA
Focus: Build
Status: Amateur
Thanks for the advice fellows.
I bought a Freud rip blade for my table saw.
It is advertised as producing a jointed surface.
I have tried a couple of different woods, and the joints look better than what I have been getting by hand jointing. The surface it leaves is smooth and clean.
On my next top, I'll rip saw the jointed side before I saw the board into two plates.
I'll rig up a proper clamp to apply pressure while gluing.
Dan

_________________
wah
Wah-wah-wah-wah
Wah


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 23 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 18 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