So, after my adventure rebuilding my 1619-4, Jay contacted me asking if I would like to take a stab at his 1967 Balladeer.

Being the adventurous-type, I naturally said, "You betcha!"

It arrived in the mail today.

We had discussed many different ways to proceed. Among these was using bearclaw spruce and the forward X-brace I used on my 1619 and using one of the rosettes I bought off eBay. We also discussed using hardwood binding instead of the plastic binding.

In the end, we decided to make a 3-piece top using straight-grain Sitka spruce like the original. I'm also leaning toward recreating the plastic binding it already has. I contacted JB and he managed to find a couple of 40th RI rosettes, one of which he was willing to sell me.

All I can say about these rosettes is: CHEAP!!! They're printed on pearloid paper which was glued into place after the guitar was finished.

Also, for the 40th RI, it looks like they used the original printing plates because all the detail of the grapes seen in the original rosette is all but gone and all the lines are thicker, which is what happens as printing plates wear out.

Jay already had a 5-point rosewood bridge, which he included in the guitar case when he shipped the guitar to me.

I've heard from a few people that the original X-bracing used by Ovation sounded really good, so I was looking forward to hearing how it sounded and to comparing to the forward X-bracing I used on my 1619.

In short, it sounds really good. I'm very impressed. It's hard to make an accurate comparison because Jay's guitar is strung with PBs and mine is strung with 80/20s. I bought a set of the same strings I put on my 1619 (Elixir 80/20 Lights) and I'm going to restring Jay's guitar so I can see how it sounds with 80/20s.

Because the bridge on Jay's guitar is lifting, I hope it doesn't pop off when I restring it for aural testing.

But, based on what I'm already hearing, I can see real benefit to using Charlie's original X-bracing. The pic below shows what braces are on the inside of Jay's guitar. If I decide to go with the original X-braces, I'll probably also use the fiberglass reinforcement strip seen in the lower bout.

I'm not sure why Charlie changed the original brace pattern unless he was a "dyin' to improve it" kind of guy. Martin tends to be a "benign neglect" kind of manufacturer, which is to say, "if it works, don't fix it." But, from what I gather from all the different brace patterns Ovation guitars had on them, and from what I read in the "Book", Charlie was always chasing after the 'perfect' brace pattern. IMO, this isn't necessarily a bad thing, but it's hard to beat the sound of his original, simple X-braces.

Another thing we discussed was the fading logos on the head stock. I've already got artwork for the Ovation logo in vector format. It will be easy enough to duplicate the Balladeer text. I've got an ALPS 5000 printer that can print gold leaf, and I'm familiar with how to create decals having done it for many years for my model airplanes. My only real concern is whether I can make sure the clear carrier sheet of the decals are able to disappear under the finish. When I get to that point, I'll do a few tests to make sure before I do it on Jay's guitar.

More to follow...

Thanks, guys.

Well, I restrung the guitar with Elixir Nanoweb 80/20 Lights (.012-.053) which are the same strings that are on my 1619 and the two guitars sound very, very similar.

The Balladeer has a little more bass on the low E and A string, but only just a little. I attribute this to the lack of tone bars and finger braces, which allow the top to resonate a little more freely.

All-in-all, I'm very impressed with how good it sounds. IMO, the best thing for this guitar is to replicate the braces and keep the guitar as original as possible.

I'm going to start putting together a list of supplies, such as top wood, braces and binding, then get the parts ordered in the next couple of weeks.

It's interesting to note the differences between this guitar and later Ovations. The first thing is the headstock is noticeably smaller, as is the size of the body. The pic below, which I got from Talbert shows this difference between the size of the 1st Gen bowl and a later generation cloth bowl.



Another thing is that the binding is narrower than on later guitars. The binding on this one is just under 3/16". The binding on later Ovations is ~1/4".

Dan, threads like this encourage voyeuristic tendencies.  Yay!!! 

    "All I can say about these rosettes is: CHEAP!!! They're printed on pearloid paper which was glued into place after the guitar was finished."

I've seen that guitar rosettes are commonly just paper labels, but it is a bit of a let down to see that this one is too. Now I wonder if that's the case for the other O rosettes also. ??

    "Another thing is that the binding is narrower than on later guitars. The binding on this one is just under 3/16". The binding on later Ovations is ~1/4"."

Did the early models have pop'd top problems that prompted the switch to wider bindings? Or maybe it was just a supplier / manufacturer change?

I'm glad you approve. :D

I hate to be the bearer of bad tidings, but it looks to me like all the O rosettes use the same cheap paper in their construction, even the (very expensive to buy) abalone rosettes.

Here's a few pics:

First, the rosette with which we're all very familiar:

Next, the dark underbelly of the beast. (DUBOB):

If we take a closer look at how it's constructed, we see that it's the same cheap pearloid paper glued to the back of the plastic rosette.

The oak leaf pattern is, either printed or silk-screened to the back of the clear plastic frame. The pearloid (or, abalone) paper is glued to the back of the frame, then the whole thing is sprayed with flat black paint.

The back of the abalone rosette I used on my 1619 looked just like this.

I don't know the answer to that question. Going to the wider bindings could have been a result of using different molded kerfings. Once I get the top off Jay's guitar I'll take a couple of pics to show what the early molded bindings look like. They don't have the same radiused (filleted) underside as what I saw on the 1619.

So, I'm back to work on 485. I wanted to finish up a 3D printed parts project for my brother.

In the meantime, I've been looking here and there at the guitar assessing it's general condition and what will need to be done during the re-top.

Not only does 485 sound really good, it also plays pretty nice. The action is a little higher at the nut end than I prefer, but it's still playable. The action at the bridge end is also pretty low.

While checking the neck angle I found the fretboard does point slightly above the top of the bridge. But, the bridge has a funny profile for an O.

I compared the bridge height to the replacement 5-point bridge. =8^0 (Yikes!)

I compared the 5-point bridge to an OEM walnut bridge and they're both the same height.

I used a small carbon fiber rod to get a basic idea of the neck angle. I laid it on the bowl.

Then, I looked at the neck from the side. It should be angled slightly down away from the bowl, but it's angled slightly up, which explains the shaved bridge.

I moved the CF rod to different positions to get an idea of how the top was warped. Overall, the top is cupped inward.

There is a noticeable bulge below the bridge.

Looking at the guitar from the top to the bottom, the reason for the deformation of the top is that the sides of the bowl in the upper bout area have warped inward. This is most apparent when compared to the lower bout in the next few photos.

I compared this guitar to all my other Ovations and this is the only one with the warping on the upper bout. All my other Os are flat in this area. Here's a close-up that shows the warped upper bout.

It will be interesting to see what happens to the neck position once I get the top off it. Ideally, 'stretching' the sides with piece that's slightly oversize will pull the neck back into proper alignment without having to heat the bowl. If 'stretching' the sides of the upper bout doesn't pull the neck into alignment, then the only other thing to do is a bowl bend, like what MWoody did recently to his 12-string.

While I was messing around in the bridge area, I decided to measure the scale. This was about 1/16" short. I used my strobe tuner and found the intonation was sharp on all six strings at the 12th fret, so this confirms that the bridge location is slightly off. It could have been glued into the wrong place when the replacement bridge was attached, or it could be a result of the top warping.

The plan is to put a new top onto the guitar and new binding. I used my CAD program to make samples of lines with differing widths to determine the thickness of plastic I'll need. The one below is the winner.

Unfortunately, while I can buy binding that's a close match to the ivory-colored binding used on Os, what I can't buy is binding that's the same thickness used in 485's binding. Which means I'll probably need to design and build a machine or a tool that will allow me to precisely thickness-shave or grind the binding.

More updates soon...

"found the intonation was sharp on all six strings"

 No wonder this was the only guitar I could sing in tune with.

Dan...holy cow...she was in pretty bad shape. It was evident that there was buzzing on the neck around the lower middle...but no one ever complained.  

I guess my question is...is it the tension/age that caused the multiple shifts...the lack of hydration on the top... 

Is it a good bet that the original 5 point was removed (and possibly damaged?) so that the guitar could be playable?

This is fascinating to watch.

It looks like it's mostly tension/age related. The splits in the lower bout probably contributed, too. 

My guess is that over time, the tension of the strings caused the top wood to cup inward. The plasticity of the bowl sides allowed them to be warped as the cupping top wood rolled the top of the sides inward.

Based on my experience with fiberglass, I'd say the sides have probably taken a set to this new shape. The tricky part is whether the upper bout sides can be warped back into shape.

Maybe. It's hard to say why the bridge was replaced. I can say that once this one comes off, it's not going to work on too many other guitars.

Thanks! I'm proceeding slowly right now so I can make a list of what needs to be done and map out the course of action so everything gets done in the right order. 

So, after a bit of thought and research online, I think I have a pretty good idea of how to proceed.

The first thing to do is to remove the strings, tuners, TRC and bridge saddle.

These were stashed into a compartmentalized container.

Next, remove the bindings. And, as it turns out, the purfling, too.

Now the edges of the top are exposed.

I used an Xacto chisel to split the glue joint holding the top into place. As you can see, the style of the kerfing is completely different.

Voila! The top is off. This poor, poor top. What a hard life it's had. More on that later.

I used the Xacto chisel to clean the kerfing of all the wood fibers. That looks 100% better already. Of note in this photo are the molded kerfing and the vertical lines around the sides of the bowl underneath the kerfing. This is an important feature. More on this later, too.

The only step remaining in the top removal is to clean out the area between the underside of the fretboard extension and the top of the neck block.

I used the same tools and techniques as on my 1619. And, for whatever reason, the progress stops right around the 15th fret. These next two pics also show the molded cloth kerfing really well.

IMO, the molded kerfing is an important factor that makes the the early Os sound so good. This, along with the simple X-bracing allows the top to vibrate really freely. The molded kerfing reminds me of the patented suspension ring used on the Adamas guitars.

Moving right along...

Nah! Just kidding!

Seriously, I used the practice top wood from my 1619 so I could check the neck geometry. (Ewww...)

One idea I had to push the sides of the bowl back into place was to cut down some Go-bars. (didn't work --the bowl flexes in all the wrong places.)

Getting back to the top. It has had a hard life. It's got several cleats used to reinforce crack repairs. These look to me like bass wood. (Think: popcycle sticks) Whomever did the repairs obviously loved epoxy as it was generously slathered on.

But, let's talke a little about how its construction. It's a 3-piece top. But, what's interesting is that it's hand-made and full of pencil marks for the alignment of the bracing. Here's a few pics that show the pencil marks, starting at the upper bout and moving down to the lower bout.

The fiberglass tape reinforcement across the lower bout looks entirely ordinary and should be easy enough to duplicate.

Noteworthy is the extra tone bar across the lower bout between the two lower legs of the X-braces. Obviously, not a part of the original construction. It was probably done as a doubler for the crack repairs.

Also interesting is the 'loose' manner in which the bracing parts were aligned to the marks during assembly. So loose that one of the reinforcement strips overlapped the sound hole and needed to be sanded to match the opening.

Since I had the top off the bowl, I was curious about comparing the 1st Gen bowl vs. a 2nd Gen bowl. If you'll recall from my The History of the Bowl thread, the 1st Gen bowl was a cloth and resin layup vacuum bagged over a male mold. The 2nd Gen bowl was also cloth and resin, but was done inside a female mold and without vacuum.

From my own knowledge of molding fiberglass parts, I know what difference these methods makes in the final part, but I was curious what if any difference it made in the bowl, i.e.: weight, resonance, etc.

Luckily, I just bought a BFLG 1978 1617 project off eBay that was missing its top and hardware, so it's a fairly accurate apples-to-apples comparison between 1st Gen and 2nd Gen.

First, the weight. The two are within ounces of each other. The 1617 weighed in at 3 lbs. 8 Oz. while 485 weighed in at 3 Lbs. 4 Oz. So, the 1st Gen. is lighter than 2nd Gen.

I tried a tap-test of both bowls. What a difference. The 1st Gen. has real tone. The 2nd Gen. sounded dull. It still had tone, but it was being muted. It was about then that a light bulb went off.

From a purely construction standpoint, the two guitars, although separated by 12 years, are nearly identical. But, the 1619 weighs 4 ounces heavier. The 2nd Gen. layup method can result in heavier pieces, but not 4 ounces in a piece this size. And, the 1617 kerfing is beefier, but not significantly heavier than what was used on 485. The only difference between these two that would add that much weight is the finish applied to the bowls.

When flying model airplanes, weight is critical. As a result, serious modelers are very weight conscious. One thing I've learned is that paint is heavy. Thick paint is really heavy. And, thick paint can easily add ounces on a piece the size of the bowls on Os. But, more importantly to guitars is that thick paint impedes the vibration of the parts.

IMO, this is just one more thing that gave the early Os the reputation of good sounding guitars. And, any Ovation knock-offs I produce will have thin paint on the bowl.

WOW Dan, 

A couple of questions...

I have read where the bracing is supposed to be a little ways away from the soundhole ... 

and I noticed that the bracing around the soundhole did not come in contact with the cross bracing.

Going for optimal soundboard response, do these two things inhibit that?

It's been a few weeks since my last update. Mostly, I've been contemplating the steps to take to bend the bowl to realign the neck. It's important to do this first as this will be the foundation for everything else to follow.

Since the bowl is a vacuum-bagged part, it's very thin as most of the resin has been scraped and squeezed out.

The second concern is the kerfing. Or, more specifically, the glue joint holding the kerfing to the bowl. Since all of this is epoxy, any or all of it could be softened by the heat being applied to the bowl.

Third and last concern is warps. The entire rim of the bowl needs to be supported equally while being heated.

After playing out the pros and cons of all the different ways, I decided on making a fixture or jig that will both push the neck and bowl into alignment, fully support the entire rim and shield the kerfing from heat.

Working in 3D CAD I came up with the design seen in the screen shots. The first shot is the basic design drawing of the jig and the parts needed. Basically, the jig consists of two parts: the neck base and clamp and the body table.

The desired neck angle when viewed from the side is 1.5 degrees. The guitar is turned upside down so the top faces down. The fretboard lies flat on a 1/4" birch ply bed which is bolted to the bench. A Stewmac neck caul is placed on the back of the neck and another 1/4" birch ply plate is screwed to the bench using 3" drywall screws.

The bowl rests on the table which is built up from 1/8" birch ply. The base of the table uses interlocking egg crate construction. The table top is built in two halves which are glued to the top of the base. I'll build the table in my gobar deck so it's flat.

There's a 1/4" birch ply ring that will get glued to the periphery of the top of the table. A 1" strip of nomex paper will get glued to the inside face of the ring to form the kerfing heat shield.

This pic shows the final parts laid out on 12" x 24" sheets, ready for the laser cutter. I'll be sending these drawings to him today or tomorrow. I decided to send these out rather than cutting them myself on my jig saw because of the accuracy. The black lines are cuts and the red lines are etches.

"Rebuild 2014 by DanSavage"

That would be an honor to have that in the bowl...an excellent idea, TPA.

While I was reading Dans post and comprehending about 10% of it (unlike Penthouse, the pictures didn't help), I thought to myself, as Dan is contemplating this bowl bend, thinking that originally it was just a re-top...he has to being saying my name like Jerry referred to Newman

Thanks!

The 'how' of applying the heat is already decided: heat gun. I also have an IR thermometer that will allow me to monitor the temperature of the bowl so it doesn't get too hot and so I know how warm it needs to get before the resin softens. As Paul correctly guessed, this probably won't be the last O bowl I bend.

There's two ways to alter the angle of the neck. One is to warp the back area below the neck inward. The other is to stretch the area around the neck pulling it away from the bridge. Of the two, pulling the neck away from the bridge is the best way. Which will happen will be determined by what part of the bowl is softened.

Preliminary tests show the area of the bowl where I'll apply the heat is the area between the of the shoulder of the upper bout and the neck.

To keep the bowl from squeezing in as it's being stretched I'll cut down some gobar rods so they fit inside the bowl across the upper bout, the waist area and the lower bout.

Heck, I think right under the Ovation tag would look great!

My laser cutting guy was able to turn around the order very quickly. I got the parts today.

I popped the parts (cut out, really) out of the carrier sheets and did a dry-run assembly of the 'table' base parts.

This next pic shows the 1-1/2 degree angle of the 'table' top.

I slid the neck base into place.

Put the 'table' top onto the base.

Placed the doublers/heat shield bases. The nomex paper strip will be glued to the inside lip of the doublers.

Here's the basic idea of how it will (should?) work. The guitar will rest on the 'table' and the neck base.

The neck base will be screwed to the work bench.

The neck caul will be put into place.

Then, the clamping plate will be screwed down to the work bench. This will pull the neck down and cause the bowl to warp away from the neck to the 1-1/2 degrees needed to bring the neck back in-line with the bridge. Once the neck is clamped, then it's time to apply the heat to re-shape (warp/bend) the bowl.

So far, so good. Next up is to break out the gobar deck, then glue the table together in preparation for the bowl bend. Pics to follow.

It's been a few weeks since my last post.

First job was to assemble the table top. I used tape as the 'hinge' to keep the two halves in alignment.



Fold the halves back to expose the joint, then run a bead of medium CA.



Remove the 'hinge', then use go-bars to secure it to the deck.



Assemble and align the lattice and use more go-bars to keep them in place. Once everything aligned, I ran a bead of medium CA along each side of the lattice and top joints. I used ZIP kicker to speed up the process.

After all the glue joints were kicked, I laid the deck on each side so I could glue the lattice joints for extra strength.

The glue is dry and I pulled the table off the deck. Next task is to assemble the 1" wide nomex cloth heat shield to the 1/4" birch ply frame. I sprayed kicker on the cloth, then applied a bead of medium CA to the frame and pressed the cloth strip. When the two parts are pressed together the glue dries in a few seconds. Repeat for the other side.



My measurements were off slightly, so I omitted the bottom plate and just used the neck caul and top clamping plate. To speed the process and assure accurate alignment of the top clamp plate I drilled pilot holes in the workbench and drew alignment marks using a Sharpie.



Before clamping, the gap between the kerfing and the table top was about 1/4".



The screws are tightened to pull body down to the table top.

The heat shields were clamped into place and an extra strip was used to protect the neck to body joint. These were only used during the first heating session. I actually found I didn't need to use the heat shields, so these were omitted during later heating sessions.



Break out my handy-dandy heat gun and IR thermometer. As you can see, ambient temp was 72.3° F.



Before any heating the neck geometry is about 1/4" or so below the top of the bridge.



It took several heating/cooling sessions. I would heat the bowl, let it cool, then pull the screws to check the change. Here we see the neck geometry is about 1/8" below the top of the bridge.



I wasn't sure how hot the fiberglass needed to be, so I started off heating it to about 160° F, which is a safe starting point. I found I was able to make more progress by heating it to higher temps. My biggest fear was overheating the fiberglass and causing it to ripple.

By the end, I was heating it to about 210° F to 230° F. In addition to heating the sides of the upper bout, I also heated up the back up the upper bout.

The neck geometry is now about 1/16" above the top of the bridge. I could have kept going, but this is plenty good, so I think this is a good stopping point.



Next is to start gathering the materials to build a new top.

Nothing but incredibly awesome. So were you suprised that the bowl could take that much heat? Did you guess at the time the bowl needed to be heated, or could you visually gauge movement? 

Yup, what danomyte said! 

Impressive all 'round Dan.  

Nifty wheels too!!   

Thanks!  

My wood order from Stewmac (SM) came in. As I noted earlier I ordered the brace wood blanks.

I also made a trip out to Aircraft Spruce (AS) in Corona, CA to pick up some spruce cap strips in the sizes used for the bracing on this guitar.

Now that I have both sets of wood in my hands, it's pretty clear they're both of comparable quality. They're both quarter-saw, high grain count with little run-out. It should work good as bracing.

Sorry for the funky yellow tinge in the photo. The CCD in my camera is dying.

I also got the top wood. Nothing left to do now, but start building the top.

Please stand by...

This is like a teaser post...

I am curious...the "patches" that were used to "stabilize" the cracks...is that the common method used? And is it really effective?

I'm guessin' you're gonna need one of them custom-made Dan Savage perfect-circle-makin' dremel / router jigs!!     

What?!  A store-bought jig???  tisk tisk tisk   (just kidding Dan) 

FWIW, I saw this really simple, clever (imho) home-made circle cutting jig...   https://www.youtube.com/watch?v=lj8kcjx201A

So when cutting these circles, I assume (yeah I know that's dangerous) you'd first route out the rosette inlay groove... then... using the same center pivot point, cut out the soundhole. ??

SOBeach - 2014-12-11 5:19 PM
What?!  A store-bought jig???  tisk tisk tisk   (just kidding Dan) 

FWIW, I saw this really simple, clever (imho) home-made circle cutting jig...   https://www.youtube.com/watch?v=lj8kcjx201A

 

So when cutting these circles, I assume (yeah I know that's dangerous) you'd first route out the rosette inlay groove... then... using the same center pivot point, cut out the soundhole. ??

Yeah, I know. Pretty cheeky of me...

But, if I don't get acceptable resulst using the store-bought tool, I'm not above making something of my own.

Correct. The rosette groove is cut first, then the sound hole.

So, as promisted here's the latest news on the Balladeer project.

I had to set aside work on it because first, because we bought a house and needed to move from the old place to the new one. Then, I had to get the house straightened up and ready for the housewarming party. Lastly, I had to get the shop set up so that I could get back to the project. Phew!

Before moving I found that the saws I had were unsuitable for cutting the top wood down to make a 3-piece top and for cutting the strip stock to make the braces, more on the braces shortly.

I had purchased the AAA Sitka spruce sound board wood from StewMac, but it comes from them in 8-1/2" width which works for a 2-piece top. Since this guitar has a 3-piece top I had to buy two sets of wood to make three 6" wide pieces. My new DEWALT 15-Amp 10-in Table Saw worked perfect for cutting down the top wood and the braces.

Speaking of braces. If you recall I'd bought some Sitka spruce from the local aviation supply house. It's really nice wood and would be perfect for this project except for one thing. It's quarter-sawn, which is good. What's bad is that the grain runs sideways through the wood instead of up and down. After a lot of thought, research and a discussion with Jay, we decided it would be best not to experiment on this guitar.

Stradivarius used sideways grain on the braces for his violins. A few luthiers have done experiments to determine whether the strength is compromised when the grain runs sideways instead of up and down and the wood is equally strong both ways. If anything, it's a little stronger when the grain runs sideways, probably because the wood behaves like a laminated piece with hard layers stacked on softer layers. What has not been done is long-term tests to see if the sideways grain warps. Maybe someday I'll try building a guitar with the grain running sideways through the braces just to see how it sounds, how long it lasts, etc. But, for this guitar I used my new table saw to cut the braces from the blanks I bought from StewMac. (sorry for the yellowed images below. The CCD on my old camera was dying)

The braces in the pic below are those I cut from the StewMac blanks. The top wood has also been cut and jointed and they're ready to be glued together.

The top wood is really nice. It has a tight grain and good lacing. It should make for a good looking, great sounding guitar.

Rather than try to glue all three pieces together in one go, I decided to glue one joint at a time.

All three pieces are joined. The second joint didn't turn out as good as the first one. I reused the hide glue from the previous day and it had thickened up so it didn't flow as easy when I painted it along the edges of the wood. This made for a thick glue joint with gaps in a few spots. So, I steamed the glue joint apart, cleaned off the old hide glue and made a fresh batch of glue. The lesson I took away from this is to always make a fresh batch of glue.

Next is to take this to the woodworking shop and have them thickness sand the wood. After that is to trace and cut the outline for the top, start cutting the rosette groove and sound hole and mark the bridge location and drill the alignment holes.

Once that is done, I can start making the braces and marking their location on the underside of the top wood.

OMG...it is looking great Dan. That grain is killer. Totally on par or better than the RI's. Thank you!

very !!!  Dan.

I was finally able to take the top wood down to the woodworking shop to have it thickness sanded.

Next I notched the top edge for the neck.

And, fit it to the guitar.

I broke out my handy-dandy bowl bending plate.

I used it because it's flat, raised up off the workbench and it's got a slot for the fingerboard.

I traced the outline of the bowl. I didn't want to trust that the hole drilled for the strap button was on-center. It wasn't. It's about 1/4" off-center. Had I relied on the strap button hole, the seams of the top would have been crooked.

Bowl shape is traced onto the bottom of the top wood.

And, it's cut out and ready for routing the rosette groove and sound hole.

I put together the Dremel plunge router/circle cutter I bought and noticed immediately one big problem. It won't allow me to cut, either the inside of the rosette groove or the sound hole. Doh!

So, I ordered a proper Dremel circle cutting attachment that can be used to cut holes/grooves from 3/4" to 12" in size.

I decided to cut some grooves anyway on the practice wood I bought to get an idea of how it's done. I tried a standard cutting bit and it worked okay. I bought a real router bit and it works much better.

The scratches you see in the surface are marks left in the shellac. I'd read that some luthiers use shellac to 'harden' the surface to prevent tear-out of the wood. While there is some fraying of the wood fibers, even when the wood is shellacked, routing without the shellac actually works better because the plastic router base drags on the shellac but it slides smoothly on the bare wood. So, I'll probably leave the wood bare.

I'll post more once the circle cutting attachment comes in and I've had a change to cut the rosette groove and sound hole.

Well, it's taken this long for Home Depot to ship my circle cutting attachment. Next time I'll just order it from Amazon and have it here in a couple of days.

I used some of the leftover practice wood to get a feel for the circle cutter. When it comes to setting it up to get the exact size circle or the depth of cut, it's definitely not a precision instrument. Once it is set up for the right size and depth, it does a pretty good job of both routing and circle cutting.

Before I began, I peeled a little bit of the rosette from the old sound board so I could get an idea of how deeply they routed the groove. I discovered that the old rosette is constructed completely different from the RI rosettes.

The RI rosette is a single piece of thin (~.010") domed pearloid plastic, probably ABS. The grapevine is printed directly onto the front of the pearloid.

The original rosettes were a two-piece affair. The pearloid is the back layer and is about .015" to .020". The front layer is ~.020" clear domed plastic. The grapevine is printed onto the front clear plastic. Also, the rosette groove is fairly deep and It looks like the rosette was epoxied into the groove before the finish was applied. The groove is about 3/64" to 1/16" deep.

Needless to say, because of how thin the RI rosette is, the groove needs to be fairly shallow so the edges of the rosette are pretty close to the surface of the top wood.

Time to get practicing. This was the first groove that was the proper size and depth.

Test the fit of the rosette. Rosette fits pretty good.

The sound hole has been cut and the inside corners have been rounded with the router.

Voila! The wood is a little darker because I sprayed it with naptha to give some contrast to the wood and rosette. Also, the lower right corner of the sound hole has a bung. This is why I wanted to practice as much as I did. Each time I went through the process I found some other pitfall that would have wrecked the top wood.

About the time I pretty much ran out of practice wood I had a fairly good feel for the process. I decided it was time to do it for real. The top wood is clamped to the work board and the center hole is drilled.

Rosette groove is routed.

Sound hole is cut.

And, routed. There is a few burn marks. With a little sanding, these will come out.

Clean up the sound hole a little bit. Fitting the top wood to the guitar body.

Rosette is slipped into place.

Phew! That was a nerve-wracking job, but the rosette fits perfectly into the groove and the sound hole is rounded nicely.

Next job is the cut and fit the braces, then glue them to the back of the sound board.

"Phew! That was a nerve-wracking job"

Phew!!! That was nerve wracking to read! Dan, the top is looking freaking awesome. Thanks!

It is interesting that the 67 continues to give up secrets to how it all came together 48 years ago. 

Moving right along.

I remembered that before I can glue the braces to the top, I needed to align the bridge.

The rosewood RI bridge was drilled for the alignment pins, but didn't have any. So, I pulled some 3/16" hardwood dowel out of the scrap pile, and made my own alignment pins.

I sanded them to make sure they won't poke through the underside of the top when installed.

Measured and marked the location of the bridge alignment pins.

And, drilled the holes.

Perfect fit.

With that done, I can mark the underside of the top and start making the braces.

Number 1 brace is cut, rounded and scalloped. X-braces are cut, notched and scalloped. Finger braces are cut.

Shown next to the original top. The only things missing is the X-brace reinforcement, which I'll cut once the braces are glued to the top, and the fiberglass strip.

I'll do the fiberglass strip first using MGS epoxy resin, before any of the braces are glued down. Then, once the resin is dry (24 hours) I'll start gluing the braces down.

Although I used hot hide glue to join the top pieces, I'll be using Hysol epoxy to glue the braces, because that's how it was done on the original. Both MGS and Hysol are aerospace-grade epoxies and both dry very hard and will transmit the vibrations very well.

The first step to building the top is to apply the fiberglass cloth reinforcement strip across the lower bout.

A layer of visqueen (Saran wrap) was laid onto the gobar deck, then the top was placed and a few gobars were put into place to keep the top flat and to keep it in place while I applied the fiberglass.

Close examination of the original told me that the factory used the same 8.5 oz. 2x2 twill cloth for this strip as was used to make the bowls. This strip looks like a single thickness of the cloth whereas the bowl uses two layers.

Typically, when glassing a surface, a layer of resin is applied with a brush, then the cloth (1/2" x 12-1/2") is put onto the resin and the cloth is wet out with the brush. This is the process I used, but the cloth looked a little dry, so I applied a thin top coat of resin.

Lastly, I put the rest of the gobars into place so the top is dead flat.

I'll let this cure overnight and I'll be ready to apply the braces tomorrow.

Hey Dan,

Exciting stuff! Hey I have a couple of questions about the fiberglass cloth reinforcement strip.

What exactly is its purpose?

Has Ovation always used it?  And if not, why did they stop?

Has any other guitar maker used it or a method like it?

Thanks

jay

Howdy Jay!

Here's what the patent has to say about the construction of the soundboard. (See: Guitar Construction US 3474697 A) 

The soundboard 16 is longitudinally tapered from a maximum thickness at its upper end to a minimum thickness at its lower end, as best shown in FIG. 2. For structural reasons it is desirable that the soundbox be of greatest strength in the region where the neck is joined thereto, and for this reason the soundboard is of greatest thickness in this upper region. The tapered configuration of the soundboard provides ample thickness in the region of the sound opening 18 and the bridge 28 while the decrease in thickness in the region of the lower bout 42 permits maximum excursion in the latter region. For added strength and durability it is desirable that the soundboard be further reinforced. Accordingly, a plurality of relatively flexible wooden ribs are *adhesively bonded to the soundboard rear surface 56 and are arranged in a manner illustrated in FIG. 6. A relatively heavy rib 64 extends transversely of the soundboard between the sound opening 18 and the upper bout 40 to reinforce the longitudinally extending grain structure of the board in the region of the neck connection. Diagonally extending ribs 66 and 68, somewhat lighter than the rib 64, cross each other below the sound opening 18 and in the vicinity of the bridge 28. Further reinforcement is provided in the bridge region by a thin gusset plate 70 secured to the rear surfaces of the ribs 66 and 68 proximate the point of crossing. Relatively light reinforcing ribs 72, 74 and 76 cooperate with the aforedescribed ribs 64, 66 and 68 to form a reinforcing structure surrounding the sound opening 18. In the lower region of minimum thickness the soundboard 16 is further flexibly reinforced by at least one elongated fabric strip 77 bonded to the rear surface 56 and extending transversely thereof.

There's a couple of interesting parts in this paragraph.

First, it says that the soundboard was longitudinally tapered from the neck to the bottom of the lower bout. I measured the original sound board and it is tapered from the top to the bottom. The upper bout is about .125" (1/8") and the lower bout is about .110". Interestingly, I measured the center of the lower bout and it tapers to a little less than .094". (3/32")

So, the center of the lower bout, which is the largest open, unsupported part was the thinest part of the whole soundboard. This means that, as the last sentence of the patent states, the purpose of the fiberglass strip is to reinforce the thinest part of the soundboard, presumably to keep it from cracking and splitting.

This brings up an interesting point. In order to completely duplicate the construction of the original would require that the sound board be tapered, not only longintudinally, but also that the center of the soundboard would need to be tapered from the edges inward.

The tapering from top to bottom could be accomplished by using a thickness sander that can be set up to sand one side thicker than the other, or one that changes the thickness as the piece moves through the machine. The other part, sanding thinner in the center as it tapers would be a bit more difficult.

So, did Ovation use use this custom thicknessed soundboard on the RI? I couldn't say. To find out, we would need to talk to the people who built them or take one apart and measure it. What I can say is that it would certainly complicate the construction process.

A lot of other guitar builders use tapered soundboards, and for the same reason --to increase the vibratory response for better sounding guitars. Usually though, they do it the opposite way, where the edges are thinner than the center. Taylor guitars don't taper the soundboard. Instead, they route a shallow groove around the periphery of the soundboard next to the kerfing so they get the same effect as tapering the thickness, but without all the trouble.

I couldn't say whether Ovation has always used the strip. We'd have to look at later models of guitars that used this original X-brace pattern and whether they had the fiberglass strip. I reviewed all the patents Charlie held and only this one mentions the strip. The 1970 German patent drawings show this strip, but I would say that is simply one to patent method of construction in Germany.

To my knowledge, no other acoustic guitar manufacturer has used fiberglass in the construction of the soundboard. The closest would be the cotton cloth used to reinforce the x-brace joint.

I'd imagine that the question on everyone's mind is, will a non-tapered soundboard, such as what I'm using on 485, sound as good as the original? I believe so, and here's why. When I was measuring the original top to determine how thin to take down, I did notice that the upper bout was a good .125", which is about the same as the wood I ordered. When I rebuilt my 1619, I intentionally had that sanded to .094". While the 1619 does sound really good, I have to use extra light strings to keep the bellying under control. So, I split the difference on this soundboard and had it sanded to .110", which is as thick as the original soundboard when measured in the area of the bridge.

Today's job is to glue, or as Charlie's patent says, 'adhesively bond' the braces to the soundboard.

Dan

Dan,

Thanks for the research and reply….

This means that, as the last sentence of the patent states, the purpose of the fiberglass strip is to reinforce the thinest part of the soundboard, presumably to keep it from cracking and splitting

 That is interesting…I wonder, since #1911 remained in pristine condition (and of course we will never know) if it was thickness sanded? Something had to be different, to make it an exception to the norm… I think. Acoustically, you couldn't tell it apart from 485.

So, did Ovation use use this custom thicknessed soundboard on the RI?

I would bet they went for look…not exactness. Having owned both..the RI is a beautiful guitar … but, imo, it fell short of replicating the feel and response…which might be attributable to the head start the originals have in “opening up”…if that is indeed a factor. And of course the originals were totally hand made. I never looked at the bracing of my RI…I wonder if they were braced the same, using the fiberglass strip???

Ok...just one more question...why use a fiberglass strip, instead of a couple more braces, like Martin did with the D45 and Ovation did with the modified X?

Who is still around that was there in 66/67?

I don't see any reason why 1911 would have been built any differently than 485. I would say that if it has the fiberglass strip, then the top was probably tapered. Since they were acoustically alike, I'd say that would make it likely they were built the same way.

It would be easy enough for someone with an RI to look inside to see the brace pattern. The factory might have added the fiberglass strip for aestetic purposes.

Speaking of opening up, I'm not sure if you're familiar with the torrefaction process for musical instruments, but the idea is to pre-age the wood so that it duplicates the cellular strucure of old wood. Basically, the wood is put into an autoclave, the oxygen is removed and the wood is brought up to a temperature of a few hundred degrees. This process 'cooks' the wood and alters the cellulose and resinous lignin as well as a substance known as hemicellulose. Yamaha calls their process. Acoustic Resonance Enhancement. (A.R.E.) Martin, Taylor and Bourgeois have all jumped onto the torrefaction bandwagon. Even Stewmac is selling torrefied wood now.

I bought some torrefied red spruce to use on my 1617. I wanted to use torrefied wood on my 1619, but couldn't find any. So, I'm going to use it on my 1617 along with the identical brace pattern I used on my 1619 to see the difference in sound between the two guitars.

The point of this is one of the characteristics of torrefied wood is that it becomes completely opaque. I compared the torrefied red spruce to 485's original top and there are a lot of areas that are opaque, which means that the wood has aged and is becoming similar to torrefied wood in cellular structure. So, this aged wood certainly has a lot to do with the difference in sound between the originals and the RI.

WRT adding braces, recall from 'The Book' that Charlie used the D-45 as the standard of sound that he was trying to duplicate. I'm sure that while he wanted to get the sound, he didn't want to have someone look inside his guitars and say that Ovation simply copied the Martin brace pattern, as so many others did, and still do. But, remember that the additional braces between the lower half of the X-braces are about sound, not structure.

Back to the build.

I decided to sand the fiberglass strip to smooth it out, and thin it slightly. To keep from scarring the inside of the top, I laid two strips of masking tape.

And, it sanded smooth. This was actually also done on the original.

Taped some visqueen to the gobar deck.

Made the center gusset using the original as a pattern.

Got the Hysol 9462 ready and clamped the top to the deck.

Brace #1, the X-braces and the gusset are all glued, er, 'adhesively bonded' and clamped.

Finger braces are 'adhesively bonded' and clamped.

I could pull the top out of the deck tomorrow, but technically, 9462 takes 72 hours to fully cure. So, I'll just leave it clamped until Thursday. In the meantime, I'll start sanding on the bowl and neck getting those ready to refinish.

I wanted to add that if you really wanted to get the opened-up sound of the original I could remake the top using torrefied Sitka spruce soundboard and braces from Stewmac.

The soundboards and uncarved brace wood isn't that expensive and I'm not so far along in the process that we couldn't take a couple of steps back.

Stewmac torrefied Sitka Spruce Soundboard
Stewmac Uncarved Guitar Braces

Once the soundboard is glued, er, 'adhesively bonded' to the body, this would become a lot more difficult. So, if you'd like to get that opened-up sound right out of the gate, now is the time to do it. I wouldn't mind taking a few steps back if you're willing to buy new wood.

There's always a chance that with this rebuild using brand new wood, 485 will sound more like a RI than an original.

If we compare the new sound board to the original one, the original one has the deep colorization of the torrefied wood.

Just something to think about.

Identical except for that tone bar across the bottom

I sanded the neck today.

I could be mistaken, but I don't think they were using EIR back in the mid-1960s, which means the beautiful rosewood veneer on the headstock is probably Brazilian.

Sanding also exposed the beautiful two-piece mahogany neck and ebony heel cap.

The two-piece neck is unusual. I wonder why.

To simulate the final look once the finish is applied I sprayed the headstock with naptha. Simply gorgeous. When I first started, the finish had darkened so much that it was hard to tell the mahogany from the rosewood. Not any more.

Here's what the back of the neck will look like once the finish is applied.

The color of the wood is actually darker than what can be seen in the photos. The flash lightens the color a little bit.

Tomorrow's task is to sand the bowl and get it ready to patch the hole where the pick-up jack used to be located. This guitar will be a pure acoustic. I'm also going to make a bone nut and use a bone saddle.