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'74 1115-1 Pacemaker Restoration

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seesquare
Posted 2024-07-07 8:41 AM (#560336 - in reply to #560335)
Subject: Re: '74 1115-1 Pacemaker Restoration


Joined:
November 2002
Posts: 3610

Location: Pacific Northwest Inland Empire
Assuredly, our fingers are crossed! Sterling work. And, there is a flaw in every masterpiece. Press on!
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DanSavage
Posted 2024-07-07 3:57 PM (#560337 - in reply to #560336)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
June 2012
Posts: 2312

Location: Pueblo West, CO
Nice job, Ken.

Thanks for the detailed write-up.
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Love O Fair
Posted 2024-07-09 11:47 AM (#560347 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
February 2016
Posts: 1796

Location: When??
@arumako - >>>The bridge bolt cracked!<<<
Oh, my. Flashbacks to nightmares of the truss rod snap heard around the world. Apparently the factory did not use very strong metals on this guitar!

>>> took a nice gouge out of the bridge and top finish<<<
Inquiring minds are curious to know what happened to the gouge in the top finish between bridge photos 1 & 2 and #3.

I'm wagering a high bet that the Bridge Doctor will do exactly what it was designed for-- though in the end, we all congratulate YOU on stellar ingenuity, tenacity and tongue-in-cheek faith!

PS: Excellent call on the Bridge Doctor solution, Dan! I think there may be one in my future (if I dare).


Edited by Love O Fair 2024-07-09 11:53 AM
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arumako
Posted 2024-07-12 2:02 AM (#560356 - in reply to #558060)
Subject: RE: '74 1115-1 Pacemaker Restoration



Joined:
October 2012
Posts: 1034

Location: Yokohama, Japan

Hey, thanks seesquare, Dan and Al. I've been messing with the bridge doctor adjustments over the last several days and started to get familiar with this very cool tool. I think it might be helpful to have a separate thread to discuss the unique application that the JLD Bridge Doctor might have with guitars manufactured by Ovation. I also think I've discovered some aspects of this tool that I'd like to share as well, but that's for another thread and another time...

As for this 1115-1 the JLD-BD works exactly as it is designed to (just as Al predicted). Installed according to the instructions provided, the JLD-BD removed the ever present buldge between the bridge and the tail end of the guitar. Tighten just a bit to allow the tension bar to spin but not wiggle and the results are immediate...

However, at this setting the JLD-BD did not help the vertical dip (the fret board extension dipping into the sound board) at all. The following pic was taken with the same tension bar settings as the pic above (it should be noted that, when strung up {DAd EJ41s} at these settings, I could not decipher any noticeable difference in the guitar's tone/voice - beautiful ringing shimmering quality with a rich natural chorus)...

vertical dip before

Spent quite a bit of time adjusting the tension bar to find the ideal dip/buldge control. Starting at the "spin w/ no wiggle" setting above, the tension bar was tightened a full 3-rotations or 1080 degrees. At this point the tension bar does not spin at all. It is not bending but it is tight. At this extreme setting, the vertical dip has been halved...

ideal setup vert

...and buldge behind the bridge has also become a dip.

ideal setup buldge

Can the tension bar be tightened some more? It CAN..., but a whole lot more turns and the structural integrity of the tail area of the guitar might be compromised. So I called this "my 1115 ideal mechanical setting" and strung her back up with EJ41s, and as BB King used to sing, "The thrill is gone, baby!" It makes sense. With this much tension, the JLD-BD is now hindering the top movement and the voice has darkened while the dynamics, the shimmer and the sparkle have been curbed considerably. Wanted to see if swapping strings to some 8/20s (as opposed to the Phosphor Bronze material used in the EJ41s) would help, and to my pleasant surprise they did! Here's the belly buldge with the guitar strung with Martin 80/20 extra lights...

bulge under tension

Interesting! You can see that the belly buldge turned belly dip at "my 1115 ideal mechanical setting" has practically flattened back up! After string tension is applied, this is how the vertical dip looks...

vert dip w strings

So this looks pretty good and the 80/20s sound decent (although not nearly as loud). Now, the question is "Has the JLD-BD improved the 1115's playability?" The answer is "Just a little bit..." I should clarify that this product is not intended to improve my guitar's string height (action). However, leveling buldge and dip in the guitar top often leads to improved playability. In this particular case, after achieving "my 1115 ideal mechanical setting," the neck angle to bridge is perfect; but after string tension is introduced to this guitar the action changes as follows (tuner at 432Hz as concert pitch and string height measured at 12 fret);

With E strings tuned down to D: 6th string - 3.50mm; 1st string - 2.70mm

With E strings tuned down to D#: 6th string - 3.70mm; 1st string - 2.85mm

With E strings tuned to E: 6th string - 4.00mm; 1st string - 3.00mm

Here's what's really weird... the JLD-BD's "my 1115 ideal mechanical setting" is holding. The repaired truss-rod is also holding and the neck relief is not changing and the neck/bowl joint is stable! Argh! Unbelievable! So what in the world is moving???

That does it! This fingerboard is coming off, and I'm going in for a truss-rod replacement! Not sure when I'll get to it, maybe in the summer? Messing with the JLD-BD has taught me so much in the last few days and has helped me to isolate the problem. There is something really weird happening in this neck's truss-rod cavity. Don't know what it is, but I'm gonna find out!

Feeling a really special attachment to this 1115-1 Pacemaker after all that we've been through. I've got some really nice kaede maple sitting in my shed so maybe a full neck rebuild (in my dreams right!)? All I know is I'll either destroy this "O" to oblivion; or repair it to glory... you know, the "If I can't have you, nobody can." syndrome! Wah ha ha ha... Wah ha ha ha ha!



Edited by arumako 2024-07-12 2:29 AM
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Love O Fair
Posted 2024-07-12 8:58 PM (#560358 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
February 2016
Posts: 1796

Location: When??
Just when we thought the plot had reached full thickness....

>>>That does it! This fingerboard is coming off<<<

This guitar is either really happy to have ever met you.. or.. it is totally regretting the day.

I was pleased to read that the BD had some influence on the top north of the bridge; that being the purpose I would be trying one for. Mine is more of a loose brace issue that has caused the top sinking around the sound hole, but has been that way for so long that I thought it may be better to initiate the closing of the gap by slowly bringing the two together at their originally-intended 'altitude' before re-gluing it instead of just stampeding in with a clamp, then once it all acclimates to itself I would be able to remove the BD. So yeah, you are right about starting a separate discussion thread about just the Bridge Doctor since it appears to have quite a variance of uses. Some direct and some indirect.. and it seems as if the indirect ones are the ones that are chain-reacting you into the abyss.. hence it would be good for others to learn at.. sorry to say.. your expense. But thank you for paying!!

Edited by Love O Fair 2024-07-12 9:03 PM
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arumako
Posted 2024-07-18 12:00 AM (#560367 - in reply to #560347)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
October 2012
Posts: 1034

Location: Yokohama, Japan

Love O Fair - 2024-07-09 1:47 AM

>>> took a nice gouge out of the bridge and top finish<<<
Inquiring minds are curious to know what happened to the gouge in the top finish between bridge photos 1 & 2 and #3.


The 3 original bridge screws used on this Pacemaker is made from aluminum - probably chosen for its light weight. Unfortunately the middle screw was CA'd into the slot and the nut was CA'd to the screw. When the screw top cracked off the remnant was quite jagged with a steep angle. Had to take a very small file to smooth out the top before I drilled into the screw. Should've waited until my composure was restored; but dug right in and slllllliiiip... ouch!

Fortunately my composure returned and was able to remove the fretboard!

fretboard

The removal was much cleaner than it might look in this picture. Took about two hours of slow heating and spatula-ing. Some of you might be able to tell just by this pic that this fretboard had been removed before. There are two plastic dowls to align the fretboard during factory installation. This fretboard had four dowls; 2 plastic and 2 wood. The wood dowls were placed randomly as seen in the next pic (the red arrows point to where the wood dowls were.

naked neck

I think the green "1115" written on the neck is from the factory. Very cool! I should find some irregularity near the neck joint of this guitar. Hmmm??? That doesn't look right!

problem area

The area in the blue circle is definitely not factory spec! The neck join cavity is all filled with some kind of adhesive. Could be epoxy, but it looks and feels like CA glue. I'm pretty sure I'm going to find some structural integrity compromising condition when I dig the adhesive out of this neck joint cavity area! So far the prospects look very promising! Hopefully some work to alleviate this guitars regret for having ever met me might be possible from here! Time to dig-in!

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arumako
Posted 2024-07-18 1:43 PM (#560368 - in reply to #560367)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
October 2012
Posts: 1034

Location: Yokohama, Japan

Before cleaning the back of the fretboard, I need to see if the neck joint cavity is really repairable. The adhesive in the cavity will need to be cleared out; and to do this. I'll use my soldering iron and just drop it on to the adhesive in the highly suspect area. If I just let the soldering iron rest on the adhesive it will melt and keep sinking until it hits wood. The process is repeated until most of the adhesive is removed. This stuff is not CA glue afterall. Definitely epoxy...

neck joint cavity

You'll notice that the spruce top stopped my sinking soldering iron, but was marked quite severely in the process. Since this area will be covered by the fretboard extension, the cosmetic condition of the top is not an issue for me. Notice the amount of wood that was removed from the neck block to get to the butt end of the truss rod! Here's a full shot for a better perspective on the size of the cavity!

cavity

It's huge, and it is the main source of this Pacemakers problems. The neck end of the truss rod was pounded lightly with a small hammer to see if the truss rod would even move that's why there's a bit of space between the neck and the butt of the truss rod. It looks like a truss rod swap was attempted in the past and the previous repair person got this far. They cut/drilled/gouged wood out from the cavity in the neck joint in an attempt to remove the rod from the butt-end. The truss rod didn't budge so they tried to pull the truss rod up and out from the headstock-end and that's why the truss rod was bent upward. When that didn't work they probably gave up, filled the cavity with epoxy and put everything back together. I've seen videos where the truss-rod is just yanked out of the neck and the thin strip of wood covering the truss-rod channel just crumbles out of the way; but that's not going to work with this Pacemaker. The thin strip covering the truss-rod channel in this Pacemaker is mahogony which won't just crumble out of the way so it's imperative to make deep cuts (down to the truss rod itself) along the length of both sides of the strip with an exacto knife, remove the wood strips and proceed to remove the truss rod. Here's the remnants of the mahogony strip...

TR channel cover 

Here's the truss rod channel cleared of the mahogony strip from several angles...

cleared channel 1  channel 2

To remove the truss rod, I continue to remove thin strips of wood from both sides of the truss rod channel with an exacto knife (this process took quite a bit of time). A thin rope was threaded into the neck joint cavity around the butt end of the truss rod...

roped TR

Lightly pulled on the rope and...

The TR

I'm face-to-face with the primary source of this Pacemakers problems! The TR channel is now completely cleared and a decision needs to be made whether to throw in another traditional one-way TR or install a more modern two-way TR. Both will require some work. For the one-way TR, I'll need to make another TR channel cover that will fit the contour of the of the existing TR channel. For the two-way TR, I'll need to fill the current TR channel with a properly contoured channel filler and route a new channel to accomodate the modern truss rod. Since both will require considerable work, I'm thinking two-way TR at this point. The more pressing question is how will I repair the neck joint cavity that currently looks like this...

neck/joint cavity

Rebuilding this area will be best accomplished by removing the neck completely; and with this much removed already, a neck reset may not be out of the question, and converting to a bolt-on configuration would be most desirable, BUT pulling the neck off of these older 111X Ovations is quite a scary task. I'm not at all sure that the neck can even be removed safely at this point! Will need to dig around to better understand how these necks are secured into the neck block before I proceed.

The saga continues! I'll be back in a few days!

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keldon85
Posted 2024-07-19 11:16 AM (#560369 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration


Joined:
July 2019
Posts: 105

Location: northern Georgia
Yes, removing the neck on an older Ovation is scary. I am rebuilding a 1617 from the early 70s (hope to have a report soon) and I decided to replace the neck. The neck was epoxied in with a large area glue joint; I basically treated it as if the neck and neck block were a single piece, like a Spanish guitar style. I used a Japanese style pull saw to cut through the neck at the body joint, similar to how Frank Ford re-did the neck on a guitar (see Frets.com -- http://frets.com/FretsPages/Luthier/Technique/Guitar/NeckReset/BCRI...) with that type of construction. He managed to re-use the original neck, and converted it to a bolt-on. His tool for cutting the neck off was an autopsy bone saw. In my case, I wanted a wider neck, so I did not use the original, but with some extra work it could have been reused. My project is almost complete, I need to spray the top and neck (lacquer) and adjust and install a Baggs LB6 pickup, hopefully by the end of the summer. If you had a router, you could use that with an appropriate jig to re-do the current truss rod channel and use a two way rod. I believe Stew-Mac has two-way rods and the router bits for them, but I believe I got mine years ago from LMI.
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keldon85
Posted 2024-07-19 11:20 AM (#560370 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration


Joined:
July 2019
Posts: 105

Location: northern Georgia
Another thing to consider when you re-do the neck or replace it, is to make sure that the distance between the bridge and the nut stays the same (if you reuse the fingerboard), otherwise your intonation will be off.
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arumako
Posted 2024-07-19 8:37 PM (#560371 - in reply to #560370)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
October 2012
Posts: 1034

Location: Yokohama, Japan

Thanks for the valuable tips Keldon85!
Back when I first started visiting this site, I was looking for ways to repair a lifted bridge on a 1117-4. At the time, BFLG heavy hitters like MWoody, seesquare and Dan Savage were doing "bowl bends" and in one of those threads, one of the veteran OFC'ers said, "it's almost impossible to remove the neck for a neck reset without destroying the top/bowl on early ovations." Don't remember who it was, but I remember the statement - I think they even went on to say the bowl bend was the "only" solution for "early" ovations. That kind of stayed with me. Since then, I've reset several Celebrity necks and K-bar equipped Ovation necks; but never a 111x model O. Bigger than the impression left by that statement is this...

dowel

That dowel in the blue circle. What is that? I keep thinking it's one of those dowels that spread when the pin is hamered into the housing. If it's part of the structural integrity of the neck joint, proper removal of the dowel/pin will be essential for a proper neck removal. I can see myself just hacking away at this thing only to find that this dowel makes neck removal "impossible." Figured this thing would have been ID'd long ago on the OFC, but my searches yielded nada! I searched the internet for some hint as well, but haven't come across anything conclusive.

There was a thread on another site that expained that an insert was made in the neck block of Os to inject adhesives into the neck joint. Is that what this is? Oh, btw, (just-in-case) the pic above was downloaded from one of Dan's previous threads, cropped and added the blue circle for easier IDing (Dan, I figured you wouldn't mind).

The gouged neck block will make it easy to accurately drill steaming holes into the neck joint. I suspect the neck will come off with a minimal amount of steam so no need for my Freezer Bag solution here. Then the mortise/tenon can be fully repaired. Install the inserts into the neck for a bolt-on conversion. Cut the TR channel for a two-way TR, glue the fret board back into position, refret, take care of minor cosmetics, string-up, set-up then I should be done...

Hope I'm not beating a dead horse here but, getting a clear ID on the above would go a long way in giving me some peace of mind with a neck removal/reset for this 1115. As always is the case, Thanks BFLG!



Edited by arumako 2024-07-19 8:39 PM
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arumako
Posted 2024-07-21 10:38 PM (#560373 - in reply to #560371)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
October 2012
Posts: 1034

Location: Yokohama, Japan

Hello OFC/BFLG! Hope you all had a good weekend. Really hot - like a sauna - over here in the Land of the Rising Son.

Been staring at that neck block black dowel-like thingamajiggy every chance I get over the weekend - wondering if it was something else. Finally decided to take a chip at it with a chisel. If it's epoxy, it'll chip. If it's a dowl the black paint should come off and reveal wood, aluminum or some other material. Lightly hammered at the dome and...

dowel chip

The dome chipped off...

block dome

It's epoxy! Of course, you all probably knew that already, right? So epoxy was injected into the neck joint after the neck and body were clamped into position? Interesting... Also, interesting is that the pic I borrowed from Dan's thread and this pic both show that the neck block has two epoxy "injection" holes. For this Pacemaker only one of the injection holes were used while the other is only partially "drilled" (the hole isn't drilled through the neck block to reach the joint).

With some added peace-of-mind, the neck joint was cleaned using my soldering gun to heat, melt and remove excess epoxy. As the work progressed my mind began to inquire if steaming this neck-off was even possible...

scary clean joint

Epoxy basically surrounds the neck joint and this stuff is intense! Set my soldering gun temperature to 110C degrees and this stuff is not budging. At 400F/200C degrees (highest setting), the epoxy melts readily. Reminded me of Hysol 9462 which (I think) withstands heat up to 250F/120C. That means this neck can't be removed with steam!? Wondering how the Mother-ship ever did neck resets on these older Os?

NOW I'm beginning to see why the OFC veteran said, "it's almost impossible to remove the neck for a neck reset without destroying the top/bowl on early ovations." I can almost hear Darth Sidius laughing and saying, "Young fool! Only now at the end, do you understand!"

Really don't want to destroy the top or the bowl... Maybe time to invest in a heat gun? New 2-way truss-rod arriving tomorrow, so I can't give-up... need more time to think! Any corrections, suggestions, advice would be most welcome/desired! Thanks for letting me share my journey OFC!



Edited by arumako 2024-07-21 11:06 PM
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seesquare
Posted 2024-07-22 9:08 AM (#560374 - in reply to #560373)
Subject: Re: '74 1115-1 Pacemaker Restoration


Joined:
November 2002
Posts: 3610

Location: Pacific Northwest Inland Empire
Stick the critter in the kitchen oven, at 275 degrees, with the neck-removal-jig attached, and cross your fingers. I think you're going to have to heat up the entire neck/block/body to get the epoxy in the joint to relinquish its hold. At least, that's my $.02, and it's not my guitar, right?!
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keldon85
Posted 2024-07-22 9:37 AM (#560376 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration


Joined:
July 2019
Posts: 105

Location: northern Georgia
This is sort of why I used a saw to cut the neck off on my 1617 project. Kaman Corp had a lot of experience using epoxies in building helicopters, and I suspect that filtered down to the group doing guitars, with them using epoxies not common to those outside of the aerospace community. Do you have an oven big enough? A heat gun would need to be used very carefully, heating the offending joint evenly without overheating the other areas. I suspect this will take much patience, and monitoring the temperature at the surface to keep from damaging it.
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Love O Fair
Posted 2024-07-24 6:26 PM (#560381 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
February 2016
Posts: 1796

Location: When??
I don't know what it's called, but a friend of mine used to sell it for Kimball Midwest (an American tool & supply company), and other companies likely have it too. It is an aerosol can product that protects surfaces from heat when the surface directly next to it is heated. The stuff my friend sold was flat out amazing. When he demonstrated it to me we took a metal rod about a foot long and sprayed half of its length.. then took a torch and heated the other end to red hot. Then he tells me to touch the spray-treated end of the rod. I told him to take a hike. So he grabs the treated end. My jaw dropped. So I touched the treated end and it was as cool as the room temp while the other end remained red hot. Again.. flat out amazing stuff.

This was around 15 years ago, so I would imagine the stuff to be quite commonly available these days, and I am probably writing about it here as an old man dinosaur in terms of current technology. Either that or it has been completely outlawed for whatever 'health and safety' reason and no longer available. Whatever... I just thought I would mention it here in the event you need to super-heat parts of the guitar while keeping the immediately-adjacent parts cool.

Edited by Love O Fair 2024-07-24 6:38 PM
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DanSavage
Posted 2024-07-25 3:14 PM (#560383 - in reply to #558060)
Subject: RE: '74 1115-1 Pacemaker Restoration



Joined:
June 2012
Posts: 2312

Location: Pueblo West, CO

Wow, Ken!

You're off the edge of the map, Mate. Here, there be monsters.

What was the original problem with the neck? Did it have too much relief? (forward bow)

I wish I'd thought of it sooner, but there's an old trick for necks with too much relief that tightening the TR won't fix.

This requires the fretboard be attached to the neck. Basically, you remove the frets, then install frets with a slightly thicker tang. As you install the frets, each one acts as a wedge that exerts pressure that causes the neck to warp backwards.

What I find interesting is the 'glue' holes in the neck block have witness marks made by a blind or 'T' nut.

The way they're installed in the neck tells me they were probably used to clamp the neck block to the bowl while the epoxy cured. Obviously, these are removed to mount the neck.

If these were used to inject epoxy into the neck joint, as it appars in the bottom hole, then it will pretty much impossible to get the neck off the bowl.

I think you're on the right track at this point. Since the fretboard is off the neck and you'r replacing the TR, I would continue on this path.

When you're ready to glue the fretboard to the neck, clamp it like is shown below so the weight of the guitar is all concentrated at the neck. This should warp it back into place. Then, when you glue the fretboard, it should pretty much fix the forward bow due to shear forces between the two pieces of wood.

If the neck still has excess forward bow that can't be taken out with the TR, you can always fall back on the thicker fret trick I described above.



Edited by DanSavage 2024-07-25 3:29 PM
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DanSavage
Posted 2024-07-25 3:22 PM (#560384 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
June 2012
Posts: 2312

Location: Pueblo West, CO
BTW, with the fretboard off the neck and the TR removed, is the neck straight for bowed forward?
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arumako
Posted 2024-07-28 11:26 PM (#560387 - in reply to #558060)
Subject: RE: '74 1115-1 Pacemaker Restoration



Joined:
October 2012
Posts: 1034

Location: Yokohama, Japan

Hey, thanks for the feedback everybody! As usual your input really helped me think through the neck removal carefully. Was a bit limited on options, but I'm glad to report that the neck's been removed and both the body and neck have survived the process with minimal damage!

seesquare - 2024-07-21 11:08 PM

Stick the critter in the kitchen oven, at 275 degrees, with the neck-removal-jig attached, and cross your fingers. I think you're going to have to heat up the entire neck/block/body to get the epoxy in the joint to relinquish its hold. At least, that's my $.02, and it's not my guitar, right?!


So I introduced my Japanese oven to my O, and we agreed that this relationship just wasn't gonna work...

J-oven

Thought maybe my BBQ grill imported from the USA might work; but naw...

BBQ-O

Maybe fill the bowl with some stuffing and enjoy some Barbecued Pacemaker?! Lol! Some seesquare humor was definitely needed at this stage of this project!

keldon85 - 2024-07-21  11:37 PM

This is sort of why I used a saw to cut the neck off on my 1617 project.  Kaman Corp had a lot of experience using epoxies in building helicopters, and I suspect that filtered down to the group doing guitars, with them using epoxies not common to those outside of the aerospace community.  Do you have an oven big enough? A heat gun would need to be used very carefully, heating the offending joint evenly without overheating the other areas.  I suspect this will take much patience, and monitoring the temperature at the surface to keep from damaging it.

Sawing the neck off at the joint would have made this a much easier project for sure, Keldon85! Your logic is definitely sound! With this Pacemaker, the neck/bowl joint itself was solid and not moving, but if the whole bowl around the neck joint is moving which I think it is, the newly bolted on neck would continue to move and cause problems. So, I figured the only way to really fix this thing was to remove the neck, reinforce the bowl, install new truss-rod, then reassemble. My fingers are crossed!

Love O Fair - 2024-07-24  8:26 AM

...Whatever... I just thought I would mention it here in the event you need to super-heat parts of the guitar while keeping the immediately-adjacent parts cool.

Thanks Al! That sounds like an awesome product. I looked all over the internet in Japanese and English and came across some aerosol sprays that are used to protect hair from heated curlers and hair dryers, but could not find anything readily available in this corner of the world. If you ever come across the product's name, please let me know. Depending on application parameters a heat protective spray could be really beneficial - especially for instruments that use a lot of space age adhesives! As you've identified, localizing heat is the key to ensuring removal doesn't end in catastrophe!

DanSavage - 2024-07-25 5:14 AM

...What I find interesting is the 'glue' holes in the neck block have witness marks made by a blind or 'T' nut.

The way they're installed in the neck tells me they were probably used to clamp the neck block to the bowl while the epoxy cured. Obviously, these are removed to mount the neck.

If these were used to inject epoxy into the neck joint, as it appars in the bottom hole, then it will pretty much impossible to get the neck off the bowl.

I think you're on the right track at this point. Since the fretboard is off the neck and you'r replacing the TR, I would continue on this path.

Thanks Dan! Yup, I installed jumbo frets with wider tangs in hopes the resistance would prevent the neck from bowing (and it did), but the issue was not neck bowing or too much relief! As a matter of fact, after removing the fret board and truss-rod from the neck, the neck is relatively straight - even the slight twist is gone! Weird, right? I think the issue is that the bowl around the neck joint has softened (for whatever reason). Still in the process of completely identifying the culprit; but in the end, I think the issues are many...

T-nuts! That's what they are! It makes sense that they were used to secure the neck blocks onto the bowls. Right, got it! The T-nuts were removed, the necks and bowls were clamped into position and the holes drilled for the T-nuts were used to fill the neck cavity with epoxy! Saving the luthier from cutting perfect fitting dove joints and securing everything with space age epoxy would decrease manufacturing process time significantly. Epoxy was used as a process improvement to cut down on labor hours and increase product output - especially in the early to mid 70s when Ovation demand was so high. They attempted the same process overseas, but instead of using space age epoxy, the overseas facilities used locally available epoxy (as a cost cutting measure)... that's probably why I see more Celebrity models with neck issues. Whatever people may think today, that is some forward "Mfg process" thinking back in a day when major manufacturers all over the world were struggling with cost/labor ratios (well, I guess that's still a manufacturing struggle today).

So with the limitations that I have, the key to removing this neck safely is localizing heat to ensure only the epoxy in the neck joint is affected. Since there seems to be 1mm to 2mm of epoxy filled space around the dove joint, the easiest way to localize heat (I think) is heating a spatula and sticking it into the epoxy while trying not to directly scorch the wood. Three spatulas were called into service for this task...

spatula

Applied direct heat to these spatulas from a gas stove flame for about 30~50 seconds and just pushed the spatulas into the epoxy. Just like the soldering guns, the epoxy gives readily, but once the epoxy returns to room temperature it gets stubborn sticky again. Had to repeat the heat-up and dig-out process for hours on end. After the epoxy was removed from the visible gaps in the dove joint, I drilled two 2.5mm holes in the sides of the dove joint (accurate drilling depth is super important). Stewmac has a product called the heat-stick that is designed to remove necks without steam. I've seen these work on Martins, Yamahas and the like, but I don't think they get hot enough so I converted my soldering guns into pseudo-heat sticks to try and get the epoxy around the bottom of the dove joint area loose. The converted soldering guns have aluminum sleeve with 2mm steel rod extensions that directly come in contact with the heating element of the soldering gun. The 2mm steel rods were inserted into the 2.5mm holes while the temperature was monitored (the temperature is just about to crest 100 C in the pic below). Tried to stabilize the heat at about 140 to 150 C.

heat stick

My psuedo heatsticks had to be left in this condition for long periods of time. Since I couldn't just leave the heat on while I was out and about, the whole set-up take down process had to be done about 8 times. Probably spent a good 6 hours in this condition (if I exclude my intermittent engagement). The idea for me was to wait until the neck basically fell out of the dove joint (instead of wiggling the neck out and risking tearout), and boy did I wait, and wait, and wait... until finally creakity, crackity, crack... with just a slight nudge and twist the neck came loose and...

bowl

Seems a bit of scorching was unavoidable, but the bowl and neck block are firmly in tact. Notice the epoxy piled up in the bottom of the dove joint. And here's the neck...

neck1

neck2

neck3

Apart from a bit of scorching and some minimal tear out, the neck/neck block dove joint are very much intact. Looks like the bowl around the neck block will need to be reinforced; and now that everything is disassembled in good condition, the fun can really start from here. Thinking about how I can convert the bolt-on neck into a no adhesive neck block assembly... the installation of the new truss-rod is going to be interesting too.

I think the TR cavity was the beginning of the demise of this Pacemaker (more about that later), but feeling really good about a full recovery at this point. Sheesh, gotta run!

Thanks for letting me share and helping me to think through this project OFC/BFLG!



Edited by arumako 2024-07-28 11:42 PM
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keldon85
Posted 2024-07-29 1:26 PM (#560388 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration


Joined:
July 2019
Posts: 105

Location: northern Georgia
Very clever! Congratulations!
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DanSavage
Posted 2024-07-30 4:53 PM (#560392 - in reply to #560388)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
June 2012
Posts: 2312

Location: Pueblo West, CO
Impressive. You're definitely earning your BFLG spurs, Ken.

Use a heat gun to soften the epoxy in the pocket and the dovetail, then use an Xacto chisel to remove the excess epoxy. (with an Ovation isn't that an oxymoron?)

Edited by DanSavage 2024-07-30 4:54 PM
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Love O Fair
Posted 2024-08-02 5:32 AM (#560399 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
February 2016
Posts: 1796

Location: When??
@Dan - >>>(with an Ovation isn't that an oxymoron?)<<<

I assume the Mothership had rail access since they likely went through a daily tanker car of epoxy!
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seesquare
Posted 2024-08-02 9:08 AM (#560400 - in reply to #560399)
Subject: Re: '74 1115-1 Pacemaker Restoration


Joined:
November 2002
Posts: 3610

Location: Pacific Northwest Inland Empire
Probably a wharf on the river, judging by the location.
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Love O Fair
Posted 2024-08-06 2:10 AM (#560422 - in reply to #558060)
Subject: Re: '74 1115-1 Pacemaker Restoration



Joined:
February 2016
Posts: 1796

Location: When??
Per the heat protection product I mentioned earlier, I spoke with my friend who used to sell it 12+ years ago.. and as I also mentioned and/or predicted, the health and safety people appear to have had their way with the aerosol good stuff, and has [possibly also] been reduced to a more limp-wristed product.

But.. but.. the good news is that it still exist in a spray bottle version... but.. but.. the bad news is that Kimball Midwest makes you jump through commercial account hoops to purchase theirs. But.. but.. more good news is that I found some other brands that appear to be exactly the same thing in both 16 ounce and 32 ounce and are readily available online.

Anyway.. here are some links. If you click the product overview user manual link on the Blue Monster brand page, it states that it is usable on trim work and cabinetry wood, so I would only guess that they are all wood-friendly.

https://www.supplyhouse.com/Blue-Monster-71024-Blue-Monster-Arctic-A...

https://squarepegsupply.com/products/rh8612733?variant=4757316717804...

https://www.zoro.com/jb-industries-heat-barrier-spray-gel-1-qt-11509...

Edited by Love O Fair 2024-08-06 2:38 AM
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