Mayes "Black & White" Eureka Grand Concert Build - Page 4

riorider · #46 01-21-2011, 08:05 AM

Very elegant, John - nice work!

Does the shellac get sanded off later?

Will you bind the soundhole, and if you do, what preparation for that do you need to make? I've always been curious about that. It seems it would be a delicate process.

Thanks for taking the photos and sharing!

Phil

JohnM · #47 01-21-2011, 08:20 AM

Quote:

Originally Posted by riorider

Very elegant, John - nice work!

Does the shellac get sanded off later?

Will you bind the soundhole, and if you do, what preparation for that do you need to make? I've always been curious about that. It seems it would be a delicate process.

Thanks for taking the photos and sharing!

Phil

Thanks Phil. And yes the shellac gets sanded off during final sanding in prep for finish.

I am not binding the soundhole. I'll be cutting the soundhole probably today. It's a simple matter of a router on a jig, and then I finish the little cutout dip area with the medallion by hand. If there were no medallion then I use a normal circle cutter on the drill press.

racman · #48 01-21-2011, 08:33 AM

That rosette looks great John. (Of course the rest of the build does as well)

John Osthoff · #49 01-21-2011, 10:13 AM

John,

It looks great ... I will be following this one more closely, cool design choices.

SuperB23 · #50 01-21-2011, 11:05 AM

Looks great John, I can tell this is going to be another Classy beauty from your shop like always!!

Rollie · #51 01-22-2011, 05:27 AM

It looks great John...The rossette is very cool and will complement the Ivory bridge ..I'm sure your scrimshaw work will really set it off nicely....I've got to get me one of those fly cutters for my drill press. It looks like a much better alternative to the dremal Stewmac circle set up that I have now...Now to try find one ...

JohnM · #52 01-26-2011, 06:57 AM

Next up is sanding the top to the correct stiffness. I don't thickness soundboards to certain thickness, but rather a target stiffness so that I can make sure the results are consistent. Here shows the top being deflection tested. I keep sanding until my target stiff is achieved and then I'm there. Low tech set-up, but really all that's needed is repeatability. some other luthiers do this as well, but I've got no clue on what numbers they shoot for. For the longest time I always did my stiffness tests by hand. I wanted to be a bit more specific when I started on the Eureka Prototypes. Actually the deflection testing didn't start until after about #8 or so if I recall correctly. I wanted to see how far I could push it before things went bad so that I could maximize response.

After the target stiffness is achieved I cut out the top shape.

I needed blocks for the rim so I cut up 4.8 board feet of 8/4 mahogany. Got enough neck and heel blocks to last me a year.

pepperboy · #53 01-26-2011, 02:28 PM

Yeah... the first build pic of my next Mayes guitar... I'm sure my neck/heel block is in there somewhere!!

Quote:

Originally Posted by JohnM

Seriously- very interesting about the stiffness testing on the tops. Something I never considered but after reading it seems like an obvious step in the process.

Looking good as always!

JohnM · #54 01-31-2011, 02:10 PM

I jump back and forth when building the body. I wanted to get the sides up to speed. One change in the build. I had to go with a non-cutaway. The sides were just barely long enough for the guitar as planned and had no extra room for a cutaway. So non-cut it is.

Bending the sides:

Sides bent sitting in mold:

Sides sanded smooth inside to 220 grit. Even though most people don't bother to look inside I enjoy making the guitar be ultra clean inside as well as out.

Putting the arch on the tail block to match the butt of the guitar:

Blocks installed:

Kerfing; I'm using Kevin Ryan's A4 kerfing/lining for the new models. They are more modern in appearance and have some advantages although they do have a couple negatives as well. They are super easy to work with and they stiffen the rim a bit more than triangular lining does. Although that stiffening is probably moot once the top an back are glued to the rim. They smell great, and also help control glue squeeze out. On the down side they are vastly more expensive, as well as very fragile. The fragility mainly comes in when routing pockets for brace legs. I've developed my own way of dealing with the downside, and despite the high cost the ease of use and time savings keep me swayed to use these for the modern style guitars.

Gluing in the lining:

Cleaning up the glue squeeze out. Don't want any trace of excess glue or slop to be there.

Rim with lning/kerfing installed.

kirkham13 · #55 01-31-2011, 05:53 PM

very cool-

Coke_zero · #56 01-31-2011, 06:39 PM

I hate it when they make it look so easy...

Fantastic looking guitar right there and it isn't even put together yet.

riorider · #57 01-31-2011, 08:10 PM

John, I think a non-cut will be great. It sure wouldn't change my mind..

Looking really good... not that it will show, but the chocolate kerfing against the dark sides looks pretty cool!!

Phil

SuperB23 · #58 02-01-2011, 11:14 AM

This thread gives me major GAS. That African Blackwood/Italian Spruce MJ-55 still haunts me from time to time. Thanks for sharing this John, I always enjoy your threads!! Even that girly guitar you are building in that other thread

.

JohnM · #59 03-13-2011, 02:31 PM

Been a while since an update! This is why I've started my Healdsburg guitars so early. It's quite the crunch for us builders to squeeze in all these extra guitars while still keeping our heads above water with our normal builds. So progress is a bit slow, but it's moving along.

Next up we have the bracing. The top bracing is an X, but then departs heavily after that. I apologize for the tease, but I've worked on this bracing scheme for over a decade, and I'm not quite ready to share. I'm sure someone has done this pattern before, but my whole system is just that, a system not just a pattern of braces. Through a series of principles, angles measurements, and properties I come to my style on these.

Moving to the back braces it's all pretty standard fare. I do use pretty small braces, and these were even smaller due to the weight, and stiffness of this particular plate. Here they are being glued on via vacuum press.

After they are glued I tape off the area right around each brace so that the back won't get scratched up too much. This shows me putting a triangular pattern on the braces.

After that I scoop the edges and sand them all smooth to 220 grit. We obsess over the insides too!

Then I'll go back and take off the tape and use a scotchbrite pad to clean up the inside. The only marks really now are fingerprints, and dust. Both of which both get cleaned up before boxing it up.

I've went back and forth on this process over the years. I've glued on the backgraft before the braces and after. Both have strong points and weaknesses from a building perspective. Gluing it on before makes it easier to glue, as well to make sure it's straight. Gluing on after makes it harder to install and make sure it's straight and it's more time consuming, but I feel it's easier to get a perfect tight fit up against each brace. I install it by slowly shaving thin pieces off using a small square to make sure it does not get crooked. Yes, we obsess about things most players never think about too!

Then gluing in the backgraft reinforcements. One of the process I still use my go bar deck over my new vacuum press for as it's easier to place them one at a time to me.

Now to "bowl sand" the rim. I need to put the same radius on the rim as I have put on the top and back so that when they are glued together they fit nicely without forcing it together. I have this shopmade jig that holds the rim level while my sanding dishes center on a wooden dowel that rocks back and forth as needed for the arch of the back.

I'll keep sanding until all marks are gone from the rim. This is about after 5-6 spins of the dish. You can see I need to go further to reach the waist, and block area. It'll take me about another 15 spins or so to get there.

JohnM · #60 03-13-2011, 02:32 PM

Now I need to notch the rim to accept the braces. This needs to be done with great care so the braces look nice and tight fit into the notches.

Then I'll carefully take micro shavings off the brace ends to match the depth I just notched in the lining.

If I've done my job right it ends up looking something like this

Then I'll go back to my go bar deck and use it to glue the back to the rim. I do the back first so I can clean up any glue squeeze out before putting the top on. I also take this opportunity to make sure all fingerprints, and such are gone.

Then I do the same for the top.

So now we have a box! Up next is the binding.