Official Luthiers Forum!

Most know that I took Ervins course and was pleased with the knowledge received.
TIME TO SHARE SOME OF THAT KNOWLEDGE!!! I have nothing to hide!!!!!! I am not trying to stir things up but pass on info.

Well to this point in my short lutherie carrier, I have built 23 guitars. That is more than some and way less than most of the pros here. Each guitar has gotten better and my guitars after Ervins class are clearly better from an acoustic standpoint. I have liked most all of my guitars, but now they are better. There was one guitar I just HATED the tone of. Just no umph!!!! A total DUD!!! I thought that part of this was that it was the only parlor (John Holls 0-12fret mold) I had made it was just that the body was smaller. From a cosmetic standpoint the guitar is beautiful (Mac ebony, slotted headstock, tons of abalone,port orford cedar top, waverly tuners etc) I originally built this guitar to be my travel guitar. The neck comes off easily and I put the entire guitar in my knapsack and carry it on a plane. But I hated the sound of the guitar and it just sat in the case.

I took this guitar to Ervins class last year knowing I hated it. Most brought guitars they liked. I took the opposite approach. I brought the one I didn't like because I wanted real criticism and feedback. I wanted to find out what gave it the properties that created the tone I didn't like. I was curious to find out if Ervins teaching were practical to building guitars and did it effect the end product. Well all of my guitars since the class have been great. But was this because I just got better or did his principles really make my guitars better.

So the experiment. Could I make a dramatic difference to this parlor by rebuilding it? The feeling from the class was that it was way overbuilt . Especially since it is a smaller guitar. It is much easier to overbuild a smaller box. Could I replace the top and make a huge difference?

The old top was about 0.110 thick piece of port orford cedar. I decided to go with a piece of Lutz from Shane this time. I used deflection testing to thickness the top. Since this box is smaller the teaching is that a greater degree of deflection is preferred. (All thing being equal, smaller guitar boxes are like a smaller drum head and so a greater degree of deflection may be required) For my OM sized guitars I shoot for a deflection of around 275-300 with my setup. L-OO's I go 300-325, SJ's only 250-275. So for this one I had a target of around 310-330. I ended up at 325 with a top that was 0.082 thick. My bracing was with a modified single tone bar pattern. One finger brace one each side and my X brace height ended up at 0.048" before capping. I did sand the back bit to thin it after gluing the top back on so that when I tapped on the top the tone was muffled if I rested my hand on the back. The goal here was to make sure the back was not just a reflector but contributing to the tone. Like an idiot I forgot to take picts of the top before gluing it on!!! I french polished the body and just finished the initial set up.

Well...good news. The same guitar with a new thinner top, lighter braced, is a totally different guitar. I am shocked at how much tone and sound this guitar has with such a small body. It is a night and day difference. Now I love this little sucker!!! Now I will travel with it again!!!! Pop it the knapsack and off it goes!!!!

This thread is not supposed to be a plug for Ervins class, but the knowledge I got in class was this was an overbuilt guitar. The REALITY was that it WAS an overbuilt guitar based on altering it in this experiment. Before his class I was clueless to WHY the guitar was a dud. After it, I had a reason for it being a dud and a direction to take it. I took that direction and I got my desired change.

One teaching we got in class is that is it way more common to over build a guitar than it is to under build it. My parlor was a classic example of overbuilding. This was exacerbated because of the smaller size body.

I hope this helps some of you by me sharing my experiment. It was well worth changing tops!!!! I will take some picts tomorrow and post them. Some may think by me changing from spruce to cedar that it might have made the biggest difference. I don't think so . I have built several cedar top guitars following these same principles and they have been nice guitars. All of my guitars now are having a consistent voice even with different body sizes or wood selection.

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Andy Z.
http://www.lazydogguitars.com

Hey Andy , thanks for the post ,I find it quite intrigueing , one question , what do the numbers reffer to when you describe the deflection testing ? what do you mean when you say you tested it to 275 or 325 ???? thanks Jody

Thanks for the info, Andy. This is the kind of info that really makes sense. I have made 2 parlors and have been planning on either burning the dud one or replacing the top...you just helped with my decision! Interesting, however, in my case. The Sitka sounds fantastic while the Redwood topped one is the dud. Of course , at that time, I knew nothing about voicing, so it's certainly in large part due to my ignorance at the time (#3 & #4).

I totally agree that our rookie inclination to over-brace the early builds creates "resurrection opportunities". I'm sure we all could benefit from such an exercise.

Looking forward to the pics. Thanks again!

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JJ
Napa, CA
http://www.DonohueGuitars.com

Andy bro - Very Well Done!

I too have a few things that I didn't like on early guitars and I just put them aside thinking that someday when I knew more, hopefully..., I would go back and fix them.

Yours is a story of how we learn in this hobby/profession and that what ever we build CAN be improved upon once one understands the problems and gains the skills to address them.

I am looking forward to seeing the pics of your travel guitar - I always loved the way that it looked.

Great read Andy. But I'm also curious about the units you use for the deflection test.

Another thing. Is your X-brace height figure correct? 0.048" = 1.2mm. Now that's light bracing!!!

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If God had wanted us to drink beer, he would have given us stomaches.

I am sure he means .48"

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

I have a couple questions about this if you don't mind.

How thick was the back? Did you do anything to it, or just retop it?

Since you were just remaking the top plate, how did you voice the top? free plate, or one of the Somogyi style tapping rigs like we used in the class?

And finally... if this guitar was finished via Tony, did you sand off all the body finish and have Tony just redo it all, or was he able to reblend the top and new bindings into the old finish.

I actually have an older guitar I am thinking of doing the same thing to.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Andy,
I'm assuming that you meant your "X" bracing ended up at just under 1/2 inch tall or .480" and not under 1/16 of an inch at .048".
Nice post. Ervin has made a difference in the skills of everyone that I know who have taken a class with him. He know what he's talking about and there's no refuting that.....his guitars tell the whole story.

I've played the guitars built by some Somogyi detractors and they tell the whole story, too....but a completely different story.

It's nice to hear that the class experience and all that you gleaned from it are being applied and showing good results in the real world.

Regards,
Kevin Gallagher/Omega Guitars

Andy
I just knew that guitar was going to be amazing one day! I just had a feeling,....
Im so glad you finally worked it out!!!! Its sooOOOOoooo beautiful, but beautiful as it may be - if it sounds like crud - its crud - I remember talking to you when you were gong to Ervins workshop, and I had the highest hopes for your being able to simply brace shave it,,,, and redefining the tone that way... but alas it was to no avail....
Im so happy its finally singing,,, Im sure the Lutz had a huge part in the resurection of the sound along with your remarkable craftsmanship, and growing knowledge of course...
Good stuff Andy!
Please post some pics of it with the new top when you can? I could look at that one allllllll day!
Cheers
Charlie

Andy, this is great timing for me. I signed up for Ervin's next class earlier this week. I'm greatly looking forward to it. Thank you for sharing this.

I'm interested in how you worked with the back, too.

Andy,

Thanks for the post. I am just rebuilding one of my mistakes too. Your point about over-building is especially timely for me.
Isn't it quite a learning experience by dissecting and rebuilding an instrument that at one time was one of your best? It's embarrassing, but worth the lesson. Thanks again,

Rich H

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Rich H
Parker CO

I actually played that guitar at the Somogyi class, it wasn't nearly as bad as Andy says it was, but I bet it is much sweeter now.....and still as beautiful as ever!

Cheers,
Greg

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Gwaltney Guitars

I will try to answer all of your question.
First...Yes the X brace was 0.48 inches not 0.048

Brock. I sanded the entire guitar body removing all of Tony's nice finish. Ouch!!!!! As far as the back goes, I don't have any data on how thick it was. My goal is to make sure the back is not just a reflector like an ovation. When I put the new top back on the back didn't appear to contribute. I use the hand on the back test that Ervin showed us. So with my ROS I just thinned it a bit until I got the response I wanted. This was easy to do since I was planning on french polishing it. Brock I also re did the binding along the top but not the back. It is french polished right now. (Not so pretty) I might eventually send the body back to Tony for a redo. As far as voicing. I didn't do any tapping like we did in class. Normally I glue the top on first and do it with the back off. Since the back was already on I couldn't voice like Ervin teaches. I had to pick what I thought was a reasonable X brace height and other brace height and I just went for it.

Jody...A loaded question. Deflection testing brings up some controversy here. Do an archive search. Basically you thin a top to a level of deflection so that each top is thinned to a measured level of "stiffness" Those numbers are my levels of deflection for MY setup. I use around a 5" weight. So with the top jointed but still rectangular, I do my measuring. (I actually install my rosette as well but don't cut out the sound hole...probably not a pure of a method) A number of 325 means that with my setup and my weight, the top deflected 0.325 inches at 0.082" thick. If this was a piece of cedar or redwood. (Less stiff woods) the top might only be 0.1 or thicker for that same degree of deflection.

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Andy Z.
http://www.lazydogguitars.com

Here are some picts. The neck was never altered. It still has Tony's finish and my old logo.
The body finish is not even close to being as nice as Tony's. It was my first attempt at French polish.
I used Robbies DVD. It was fun to try it. I can always have Tony refinish the body

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Andy Z.
http://www.lazydogguitars.com

How much weight do you use to measure soundboard deflection? At what point so you measure the 250 to 350 deflection you described? I have and have studied both of Simlnoff's books but I don't have a clear picture of this measurement. Can you provide a picture?

Steve Brown

That's great Andy. I too re-topped the guitar I brought to Ervin's class, using the principles I learned there to guide me. The difference in tone was huge and much closer to the way I wanted it to sound. It was quite an eye-opening experience for me.

andy thanks for replying to my question

Steve brown , I was thrown a little too, I think Siminoff deflection testes after the top is braced,,, Jody

Just to back up Andy's comments - That guitar did suck!
I'm glad you had the time to get it fixed. I want to play it now.

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Okay, okay...it sucked

GG

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Gwaltney Guitars

Steve
My deflection method is as follows
1. Join the top plates and clean them up
2. I actually then inlay the rosette next. (Not as pure of a method but inlaying a rosette on a very thin top is a bit risky for me.
3. clean up rosette side. (Plate still too thick)
4. Start deflection testing. I use a 5# weight and measure at the center of the plate.
5. Thickness from back side of top plate and then remeasure.
6. Keep doing this until you achieve the deflection you want
A purist would use a bar that evenly distributes the weight, but I have been using this dumbell and it works for me
7. Once I reach my final thickness, I cut out the sound hole and trim the plate to the shape of the guitar
I hope this helps

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Andy Z.
http://www.lazydogguitars.com

Andy,
Thanks for the post.

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Jim Watts
http://jameswattsguitars.com

Hey Andy , thanks for sharing ,, if you put any sort of flat piece of metal or wood under your dumbbell , it would distribute the weight more evenly... but maybe you dont want to change because this is how you have been refferencing . thanks Jody

I was having a lot of fun thinking about 1.2mm high x-braces! Cutting the lap joint would be interesting.

The deflection testing setup looks nice and easy. It'd be a good way to get more consistent results. Are the deflection measurements based on anything? Or are they just something you've come up with that feels right?

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If God had wanted us to drink beer, he would have given us stomaches.

Andy thank you for sharing your experience and corrective action. It sounds to me like you have arrived at a new place in your building..... congratulations on that.

I wouldn't have the intestinal fortitude to remove and replace the top then strip off the finish on a completed guitar. Especially that one, as it looks like brazilian rosewood to me. Does it help being a surgeon?

AZ...a Surgeon could never do this! An Anesthesiologist, however has the means at his disposal to set his own personal mood that allows him to reach inside himself and accomplish tasks that mere mortals can only dream about.

Truly a courageous act...and I'm sure a significant learning experience.

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JJ
Napa, CA
http://www.DonohueGuitars.com