New build question

[James Sanford]

I have recently completed my number 12. I am having a problem which I do not understand.

I did not string up in the white but waited until I finished it. I used J74's which are what I normally use. I brought the mando up to pitch and checked everything. All seemed fine. I left it overnight and then rechecked and the pitch had dropped which did not surprise me so I redid it, played it a bit and then left it overnight again. The pitch again dropped so I retuned and played it and then put it up again.

You probably see where this is going. I can now notice a change in string height which is pretty substantial. It appears that string pull is trying to pull the tail and head stock together which is normal to a certain extent. I cannot notice any cracks or other changes which would account for this.

I used a fixed truss rod of carbon fiber (two 1/8" x 3/8" pieces epoxied together and then epoxied in the neck) and even installed a 1/4" id carbon fiber tube from the neck block (cherry) into the tail block. This was angled from the top of neck block to the bottom of the tail block.

The top is adirondack spruce and the ribs and back are cherry, the neck is cherry with a 1/8" piece of purple heart sandwiched between the two sides.

I do not notice any dip in the top or any caving of the top near the tail piece. As a matter of fact I left the top in that area rather thick (3.5 to 4 mm).

So... I guess my question is what is going on?

The only thing that makes any sense is that the whole neck joint is collapsing or moving within the body or the whole body is flexing at the neck joint.

I will add pictures.

[James Sanford]

I have reviewed the neck joint further and can now detect a hairline seperation between the heel of the neck and the back so I guess that answers my question. I think it moved enough finally to be detectable by eye.

Now I will try to decide what to do.

I am using Titebond. Would this contribute to this situation?

[Bill Snyder]

James, Titebond will creep over time. It should not be showing up yet. How fresh is your Titebond? Not how long ago did you purchase it but when was it manufactured. If it is over 1 year old it is recommended that you replace it. Many builders won't use it if it is over 6 months old.
There is a code on the bottle. They changed the format a few years ago but here is how to read the current codes:
The first digit represents A for America (made in), the second digit is the last digit of the year of manufacture, the third and fourth digits represent the month, the fifth and sixth digits represent the day of the month and the last four digits represent the lot number.

[Steve Sorensen]

Titebond I, II or III?

[James Sanford]

Titebond 1 (original).

[James Sanford]

James, Titebond will creep over time. It should not be showing up yet. How fresh is your Titebond? Not how long ago did you purchase it but when was it manufactured. If it is over 1 year old it is recommended that you replace it. Many builders won't use it if it is over 6 months old.
There is a code on the bottle. They changed the format a few years ago but here is how to read the current codes:
The first digit represents A for America (made in), the second digit is the last digit of the year of manufacture, the third and fourth digits represent the month, the fifth and sixth digits represent the day of the month and the last four digits represent the lot number.

Bill, the number is A006160058 which if I understand correctly is A=America, 0=2010, 06=June, 16=16th day, 0058=lot number. I guess this confirms that the glue is too old.

I will replace the glue I have at once and store this information for future reference. Thanks

[Bill Snyder]

To paraphrase Mario Proulx - glue is cheap, always use fresh glue. You might also consider using hide glue for your critical joints. If everything fits well (it needs to no matter which glue you are using) then the hide glue should not be too problematic to use and it can be "same day fresh".

[Rodney Riley]

Ahh, the wealth of information here...

[James Sanford]

Added photos.

[sunburst]

James, what kind of neck joint did you use? Unless your Titebond has been subjected to freezing or excessive heat, it should hold a good neck joint even if it is "out of date". The mandolin has only been glued a short time, has not been subjected to excessive heat, moisture, or humidity extremes (I assume) in it's short life. While using fresh glues and adhesives is always good practice, I suspect a problem with the neck joint when there is a partial failure that soon.

[Max Girouard]

James, Titebond will creep over time. It should not be showing up yet. How fresh is your Titebond? Not how long ago did you purchase it but when was it manufactured. If it is over 1 year old it is recommended that you replace it. Many builders won't use it if it is over 6 months old.
There is a code on the bottle. They changed the format a few years ago but here is how to read the current codes:
The first digit represents A for America (made in), the second digit is the last digit of the year of manufacture, the third and fourth digits represent the month, the fifth and sixth digits represent the day of the month and the last four digits represent the lot number.

Curflunk, kudump dump. The sound of glue bottles being thrown away as people realize the expiration date has passed! Hey guys and gals, make sure you recyle those bottles! This holds true for almost any type of adhesive, or even finish. Make sure it is fresh, and as Bill pointed out, hide glue can be made fresh daily as it can be stored indefinitly while dry. Plus, hide glue can be composted with all the hosehold scraps to use in your garden. The same can't be said for Titebond. There are many threads on Titebond vs. hide glue, and I must admit, both have thier place in my shop, but for a neck joint hide glue is a must (in my shop). If you are seeing neck movement, I would have to assume it was the neck joint and not the glue. I used Titebond for a few mandolins and never had a problem. The fit of the joint is the most important issue.

[James Sanford]

James, what kind of neck joint did you use? Unless your Titebond has been subjected to freezing or excessive heat, it should hold a good neck joint even if it is "out of date". The mandolin has only been glued a short time, has not been subjected to excessive heat, moisture, or humidity extremes (I assume) in it's short life. While using fresh glues and adhesives is always good practice, I suspect a problem with the neck joint when there is a partial failure that soon.

The neck joint is a similar to the joint Siminoff uses. the neck is screwed to the neck block with two screws. Through the block into the end of the neck. One high, one low. I do not believe the joint itself moved, I believe the heel of the neck did not adhere to the back. This may have been due to poor contact between the heel and the back. In other words an operator mistake.

I would appreciate any thoughts as the best way to fix this if practical. If not I may take it apart and redo it.

[Steve Sorensen]

My first though was that you might have cracked the neck block as you glued in the neck -- movement at the cracked joined portion of the dovetail/block and the body . . .

[sunburst]

Did you put the neck in before putting the back on? If so, did you sand the back of the rim on a big, flat sanding board to true it up for the back? Doing that tends to round over the heel of the neck and can cause poor contact between the heel and the back. If, on the other hand, you glued the back on first then the neck, it could have simply been poor contact.
What to do now:
If, as I suspect, the back has to be force into contact with the heel, simply re-gluing and clamping will probably not work in the long run (DAMHIKT), so fitting and gluing a tapered shim into the gap and clamping the joint in the best bet. The glue that is in there needs to be removed first. That can be done with De-Glue Goo and a palette knife, sandpaper, or any method you can come up with.

[sunburst]

Did you put the neck in before putting the back on? If so, did you sand the back of the rim on a big, flat sanding board to true it up for the back? Doing that tends to round over the heel of the neck and can cause poor contact between the heel and the back. If, on the other hand, you glued the back on first then the neck, it could have simply been poor contact.
What to do now:
If, as I suspect, the back has to be force into contact with the heel, simply re-gluing and clamping will probably not work in the long run (DAMHIKT), so fitting and gluing a tapered shim into the gap and clamping the joint in the best bet. The glue that is in there needs to be removed first. That can be done with De-Glue Goo and a palette knife, sandpaper, or any method you can come up with.

[James Sanford]

John,

I installed the neck prior to putting the back on but did not sand it after the assembly. I sanded the ribs seperately prior to assembly. I checked the level of neck heel and the ribs using a straight edge prior to glue up. I think the problem came from the back itself.

Thanks for the hint on fixing. I will try that first.

[Bernie Daniel]

James, ...[Titebond]...changed the format a few years ago but here is how to read the current codes:
The first digit represents A for America (made in), the second digit is the last digit of the year of manufacture, the third and fourth digits represent the month, the fifth and sixth digits represent the day of the month and the last four digits represent the lot number.

Great information Bill, Thanks.

And now, since you are such a stickler for details let me be the first to mention that "A" is not a digit!

[Bill Snyder]

Bernie, I must confess I did not compose that tidbit but copied it for my reference two or three years ago when I realized that the date code had changed. I am not sure whether I got that off of Franklin's website or another forum.

[Pete Summers]

Just a bit of clarification ---

This comes up frequently on this site and the Fiddle Forum -- when posters refer to "Titebond" glue, to what are they referring??

Titebond is a brand name of glues made by Franklin International. It is not a type of glue. Titebond markets a liquid hide glue under the same name as its original Elmer's style wood glue. I am always confused when I read these posts as to exactly which of their glues is meant by the term "Titebond."

Also, most luthiers I've read claim that the liquid hide glue sold by Titebond is inferior to hot hide glue made from power. Yes?

[Rick Lindstrom]

Just a bit of clarification ---

This comes up frequently on this site and the Fiddle Forum -- when posters refer to "Titebond" glue, to what are they referring??

Titebond is a brand name of glues made by Franklin International. It is not a type of glue. Titebond markets a liquid hide glue under the same name as its original Elmer's style wood glue. I am always confused when I read these posts as to exactly which of their glues is meant by the term "Titebond."

Also, most luthiers I've read claim that the liquid hide glue sold by Titebond is inferior to hot hide glue made from power. Yes?

Well- a lot of us guys are old-timers, and we go back to the day when there really was only one kind of Titebond- an aliphatic resin yellow glue. I've used gallons of it at least.

So, today, if I say "Titebond", that's what I mean, but if I remember, I qualify it with "original", which I believe is one of the designations now for the yellow aliphatic resin version.

I think Elmer's has the same thing, sold as "Carpenter's Wood Glue".

Rick

[Bill Snyder]

Normally when Titebond is used here it is referring to the original, red label Titebond carpenter's glue manufactured by Franklin. Franklin has nothing to do with any of the Elmer's products.

[sunburst]

Oh, never mind. Two posts while I was typing...

[James Sanford]

I wonder....does the angle of the headstock relative to the plane of the neck have any relationship to string pull? I do not remember seeing this discussed previously.

[Rick Lindstrom]

I wonder....does the angle of the headstock relative to the plane of the neck have any relationship to string pull? I do not remember seeing this discussed previously.

Not really. Correct peghead angle is mostly important to ensure that the strings have a decent break angle across the nut and make good contact with it.

More angle increases the down pressure on the nut, and also creates more friction in the nut slots when tuning.

Rick

[James Sanford]

OK.... so here is an update on my "operator's error".

I have removed the back and removed the neck, refitted the neck, checked on all areas to insure proper fit of the ribs, back and etc.

I have ordered a glue pot!!!!!! I give in.........................

When it gets here I will fire her up and reglue this sucker with hide glue and dare it to fail. Off to the wood pile if it does.

Wish me luck.

ps: I really do think I had a problem with the "old Titebond". When I steamed the neck out it only took maybe 15 seconds of heat for it to release. This seems too quick if proper adhesion had occured.