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Location: Keepin' It Weird in Portland, OR | Fascinating, and apparently much more difficult than I thought.
Good Work, Dan. 
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Location: When?? | Ken.. I hope you're paying attention to this. You and Vincent have some real work ahead of you!
Edited by Love O Fair 2018-06-26 7:15 PM
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Location: Yokohama, Japan | DanSavage - 2018-06-26 6:08 AM
Trust me, Al. Doing the 'mad scientist' thing isn't my idea of fun.
Hey Dan! I really appreciate the love and sheer effort you're putting into this. A testament to the true Luthier's Spirit in you! If the Chapin family are viewing this thread at all it's gotta be "a tear jerker" thread if there ever was one! Sheesh, even I'm getting a little emotional on this one...
I'm afraid Vincent won't get this thorough a treatment, Al. I'll do my best to find a match, but good mahogany is hard to come by over here. Once I reach Dan's "stage 1" proficiency, I'm going to lightly do a tan/brown sunburst, and call it good. That's what I'm doing for my CS249-4Y. It ain't perfect, but it'll be good enough to resurrect the original value of the guitar.
As always, thanks for sharing your journey immaculately Dan! |
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Location: Lake Forest, CA | moody, p.i. - 2018-06-26 2:11 PM
When you stop and think about it, fixing the headstock is the really difficult part of this project. Retopping it is something Dan has done a number of times on various Ovations (twice for me).;..
It is. I always start with the most difficult task, then work toward the easiest. |
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Location: Lake Forest, CA | d'ovation - 2018-06-26 2:52 PM
Very interesting. So your approach is a minimum patch, possibly with objective to maintain as much of the original as possible. An alternative could also be to take some more of the treble side off to create a pleasing looking more symmetrical and unique outcome if the "blending" does not work well. Sometimes, if hiding a repair does not work well, emphasizing it may be a better approach.
Thanks.
Yes, I always attempt to preserve as much of the original as possible.
I could have done that, but not only was the ear broken off, but a lot of material from the back of the head stock was taken with it. It was sort of like a deep gouge.
I understand what you mean. When repairing guitars, some luthiers do not attempt to visually hide the repair. Instead, they strive to make it so you can't feel the repair.
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Location: Lake Forest, CA | Old Man Arthur - 2018-06-26 3:12 PM
Fascinating, and apparently much more difficult than I thought.
Good Work, Dan.
Thanks, Art.
The actual woodworking needed to shape the patch is pretty straightforward and not very difficult at all.
I spent as much time as I did because I wanted to get as close of a match to the surrounding wood as I could. |
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Location: SoCal | Dan, are you going to do any work on the preamp, ie, clean connections, make sure there are no hisses and pops, etc? I don't know if Ms. Chapin realizes it, but she's going to get a like new guitar with all of her father's mojo intact..... |
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Location: NJ | I was at good will and bought a program from a harry chapin show... I opened it and it was signed!!!!!! |
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Location: Lake Forest, CA | Paul,
I usually don't do anything to the preamps other than to re-install and make sure it works.
Yes, that's the idea. A brand-new 40-year old guitar.
Al,
Very cool. I hope you bought it on the spot. I know I would have. |
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Location: NJ | I did |
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Location: Lake Forest, CA | Moving right along...
First job of the top is to joint it. I took the top to the sander on Friday so that I could work on it all weekend. 
Top is thickness sanded, fitted to the top, outline cut and bridge fitted.
Sound hole is cut.
Rosette hasn't yet been fitted to the neck yet. This is just to confirm the rosette will be able to be mounted in the right spot.
Saddle/pick-up is fitted. Interestingly, this is a custom saddle. Not only do the individual saddle pieces look like bone, but the compensation has been changed from the stock saddle. There are other areas of the guitar that have been customized. More on that later.
Top is ready for braces.
Braces cut, shaped and ready to be glued. If you look closely at the original top you can see slight discoloration between the 1st and 2nd cross braces and again below the 4th braces and the lower bout of the guitar.
At some point in this guitar's life, someone, with some skills I might add, carefully used a small surface grinder/sander to remove wood from the underside of the top. This was not done at the factory because the epoxy used to glue the rosette has been ground away to the same level as the surrounding wood. Also, the area where the top has been removed is a lighter color. This happens whenever wood is removed. As the wood oxidizes, it gets darker.
If you compare the color of the top around the braces to the wood that has been ground away then to the area where I split the wood removing the top, you can see that it goes from dark to light. The wood most freshly exposed to the air is always the lightest. The wood exposed to the air the longest will always be the darkest.
I thought about it and the only reason I can come up with why someone would grind away the inside of the top is to thin it in order to free it up and make it sound better.
One of the things I've noticed about nylon string Ovation guitars is that they tend to sound stiff. I don't think it's the brace pattern because variations of the double-fan has been used successfully on many classical guitars.
So, to address this, this top is .097" thick with no taper. The braces will not be tucked. And, I've tapered the ends of the cross-braces to free up the top even more. I'm looking forward to how this sounds.
Braces being glued.
As I was saying the tops on Ovations are a little on the thick side. I recall reading a memo from Charlie on the Ovation Tribute site asking that the builders be careful to maintain this top thickness. This one must have been one of those in question. The top tapers from .140" down to .120". Unfortunately, there was a ripple-effect of the top being too thick. In this case, the gap between the underside of the fretboard and the top of the neck block/lining is also about .140" thick. (Waah!)
With the thinner top and wider gap I had no choice but to use filler pieces that were about 1/16" (.063") thick. Here they are glued to the lining. I thought about what different materials to use. In the end I decided that torrefied Adi spruce would be the best to transmit the vibrations to the body.
Filler pieces sanded to shape.
And, the top is being glued to the body.
One of the common problems with Ovation guitars of this vintage is they almost always need a neck-reset. This one is no different. Ovation guitars of this vintage have necks that are glued into the mahogany neck block. So, there are really only two ways to do a neck reset. The first is to remove the neck from the block, then perform a conventional neck reset. The other way is to use a heat source to soften the epoxy of the bowl and warp it so the neck angle is correct.
I decided to take a different tack on this guitar. The reason why Ovation guitar bowls can stay rigid with no internal braces is because once the top is joined to it, they form a monocoque structure. A common monocoque structure everyone is familiar with is an egg.
Anyone who's removed a top from an Ovation has noticed how easy it is to flex the bowl. So, it occurred to me that instead of doing a conventional neck reset or doing a hot bowl bend, I could simply warp the bowl so the neck takes a new angle, then glue the top down to the bowl and voila! Instant neck reset. Will it work? I'll find out tomorrow.
So, let me explain what you're seeing in the photo. First, I clamped the neck and adjusted the angle so that I could flex the bowl down and it would rest on the adjustable feet to the correct height. Then, I put a couple of sand bags in the bowl to hold it down against the feet. Then, I used luthier rubber bands to clamp my original bowl-bend jig to hold the top flat and to squeeze the glue joint all the way round the bowl.
We'll see how it turned out tomorrow.
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Location: SoCal | Love this stuff ! Can't do any myself, but I love it!
Wonder if Jen Chapin is watching this process?
Edited by moody, p.i. 2018-07-01 8:32 PM
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Location: Yokohama, Japan | DanSavage - 2018-07-01 8:55 AM
I decided to take a different tack on this guitar. The reason why Ovation guitar bowls can stay rigid with no internal braces is because once the top is joined to it, they form a monocoque structure. A common monocoque structure everyone is familiar with is an egg.
Anyone who's removed a top from an Ovation has noticed how easy it is to flex the bowl. So, it occurred to me that instead of doing a conventional neck reset or doing a hot bowl bend, I could simply warp the bowl so the neck takes a new angle, then glue the top down to the bowl and voila! Instant neck reset. Will it work? I'll find out tomorrow.
Incredible work Dan. Lots of interesting detail and innovative thinking! Hope it's okay to ask a question..., but when you flex the bowl to do the neck reset, the "flatness" of the bowl will be compromised in different areas... like curling around the outer sides where the bowl is widest. I suspect the the clamping pressure will keep it all together, but once the adhesives have dried wouldn't there be some stress to the top from the bowl trying to get back into shape? Really interesting stuff! Thanks for sharing! |
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Location: Lake Forest, CA | arumako - 2018-07-01 7:30 PM Incredible work Dan. Lots of interesting detail and innovative thinking! Hope it's okay to ask a question..., but when you flex the bowl to do the neck reset, the "flatness" of the bowl will be compromised in different areas... like curling around the outer sides where the bowl is widest. I suspect the the clamping pressure will keep it all together, but once the adhesives have dried wouldn't there be some stress to the top from the bowl trying to get back into shape? Really interesting stuff! Thanks for sharing! Thanks, Ken. In theory, yes, the 'flatness' is compromised. In practice, the compromise is so small as to be insignificant. To warp the bowl only required about 15 lbs. of weight inside the bowl, which isn't really a lot. Jigging the guitar in this fashion to re-align the neck elongated the bowl. Once the guitar is removed from the jig, the loads on the top from the bowl trying to assume its former shape will be in compression. Again, we're only talking about a few pounds. There is a small amount of shear load up near the neck, but it's pretty small. So, the answer to your question is, yes. The bowl will try assume it's previous shape. But, when you spread the load across the entire lining surrounding the bowl, the stress, or load, should be well withing the top's abilitiy to manage it. In theory. We'll find out tomorrow once I take the guitar out of the jig. Dan |
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Location: Indiana | Fascinating... doing my best Spock imitation. |
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Location: Canada | Wow this treatise is beyond my physics and engineering comprehension but I am awaiting the outcome. May the forces be with you. |
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Location: Texas | Dan...it is fascinating how with every project, some new aspect crops up. Totally speaks to your ability to adjust, on the go, to different situations that present themselves. I mean...it is the same shaped bowl, with a neck and a top. You would think it would be cookie cutter! But nooooooooooooooooooooooooooooooo. So thanks again for taking the time to show and walk us through your journey of rebuilding Harrys guitar. |
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Location: When?? | @Dan - >>> the stress, or load, should be well withing the top's abilitiy to manage it. In theory.<<<
Assuming I have followed correctly, if the bowl's own hysteresis plans don't want to behave as your theory is hoping after all is set, how would you know for sure? There doesn't seem to be a way to measure it. So.. could the bowl then be oh-so-lightly warmed and cooled in wider zones immediately adjacent to the stress point to equalize itself slightly outward and away? A little insurance. I mean, to the point to cause less distortion than is detectable to the eye or feel of course, though still enough to possibly disburse a small bit of the pressure (pound or two) that may, over time, be enough to prompt a separation or buckle. Again.. assuming that I have followed correctly. I admit, there WAS a reason they fired me from NASA after only a few minutes.
Edited by Love O Fair 2018-07-03 12:09 AM
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Location: Lake Forest, CA | Thanks everyone.
I pulled the guitar out of the jig and the warp worked better than I had hoped it would.
I expected some spring-back, but there was absolutely none. The neck angle is exactly the same out of the jig as it was when the guitar was clamped down.
Next job is to route the channels for the purfling and binding. I'll be starting that job this afternoon.
Jay,
Yes, it's the same shape as other Ovations. The distorting I did to the bowl actually helped bring the guitar back to factory specs.
Al,
The bowl is pretty easy to warp when the top is off. When I re-topped Jay's guitar I heated up the bowl to soften the epoxy, then warped it and let it cool so the epoxy could take a new set. It needs to be more than oh-so-lightly warmed, though. It has to be heated up evenly across the upper bout to almost 300 degrees. It took several heating/cooling cycles to accomplish.
In contrast this was much, much easier. All I did was to distort the bowl so the neck angle was correct, then glue and clamp the top into place, then Voila! Instant neck reset. |
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Location: Muenster/Germany | Wow, that was a courageous act. I can understand that the longitudian angle of the neck is (relatively) easy to manage but I would have been afraid to torque the neck in the rectangular direction to this (Do you know what I mean, I don´t know how to explain that in english). I think the perfect crabbing was quite complicated. Chapeau! And again all this is a new exciting serial. Thankfully none of my old Ovations is in need of a neckreset at the moment. With the bolt-on necks it is soo easy. |
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Location: When?? | @Dan - >>>almost 300 degrees<<<
Holy moley. "Neck & Bowl" seem to have more in common with "Body & Fender" than I thought. Anyway, congratulations on the success of your method. Always a pleasure to learn from you!
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Location: Lake Forest, CA | DetlefMichel - 2018-07-03 10:35 AM
Wow, that was a courageous act. I can understand that the longitudian angle of the neck is (relatively) easy to manage but I would have been afraid to torque the neck in the rectangular direction to this (Do you know what I mean, I don´t know how to explain that in english). I think the perfect crabbing was quite complicated. Chapeau! And again all this is a new exciting serial. Thankfully none of my old Ovations is in need of a neck reset at the moment. With the bolt-on necks it is soo easy.
Yes, I understand what you mean. One of my concerns was twisting the body relative to the neck. So, I was careful to measure them to make sure the neck and body remained square to each other with no twisting.
When locating the top and later on, the bridge, I always align these to the neck, itself. To do this, I lay a straight edge along each side of the neck and mark the positions at the bottom of the bowl. I measure the distance between the two marks and I use this is the center line of the guitar. The center line of the top is aligned here as well as the center of the bridge. |
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Location: Lake Forest, CA | Love O Fair - 2018-07-03 11:04 AM
@Dan - >>>almost 300 degrees<<<
Holy moley. "Neck & Bowl" seem to have more in common with "Body & Fender" than I thought. Anyway, congratulations on the success of your method. Always a pleasure to learn from you!
Yeah, that temperature seems a little high.
I went back to Jay's guitar thread. It was only 210° F to 230° F.
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Location: SoCal | I suspect that it's only going to be a few more weeks before I get to go to Dan's and try this sucker out!
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Location: Lake Forest, CA | Yep. I'm working to have it done by the end of the month. |
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Harry Chapin's 1977 1613-4...
