The odd couple gets married

[Dave Bagwill]

Good advice, Kevin!

This is the most un-coupled configuration of bracing I've tried. The back braces are only inlet at the top bout - the buttress brace. And the A frame is inlet into the headblock and then the cross brace in the lower bout only.

So it should be loose! And light! The word 'implosion' comes to mind, but it is overriden by my innate recklessness, uh...innate sense of adventure..

[Dave Bagwill]

The top is gluing as I type.
I normally use rubber bands, I like using rubber bands, thought I might try something different.
I first thought about using one end onlt of spool clamps - I've drilled holes in the MegaMold at the end of all the slots, just the size of the bolt heads, so I can slip bolts in and out easily. I attach a pic showing what I mean. Problem is, the spools are really too large to get just the coverage I wanted around the rim. Though I do like spool clamps, and they work easy on the MM - especially at the blocks, give you that little extra force.

I finally settled on using longish bolts, just slipped into the slots with the pvc as a spacer, and the mdf tab up above with a washer and wing nut to tighten.
It's boss. Boss=good. Went quickly, good squeeze-out.

I do fuss a lot with the top fit before gluing. With the A-frame top, the only inlet is the crossbrace; so I made that notch as accurate as I could, sneaking up on the final width so that the brace snapped into place when all was well. I was confident enough that I actually applied the glue to the rim outside the mold, laid the top flat and pressed the rim onto the mold, heard the 'snap', then just picked it up and put it in the mold and tightened the tabs.

[Kevin in California]

I take it the tape is to keep glue squeeze out off your kerfing? Have you done this before, does it work?

Kevin

[Dave Bagwill]

For me, it works very well. Only takes about a minute or two, and if it does not catch all of it,, it catches almost all. Especially with the Poplar that is so white, I wanted to be extra careful.

I will say this too: I'm using fish glue for the first time, and it's thicker than Titebond, and has a good tackiness almost right away that keeps things from slip slidin' around, and the squeeze out is not as runny.

[Fred Blom]

Dave,
Would you take a moment to explain the technique you use to shape your braces? My top and back braces evoke a "crudeness" I don't see on yours, even though I have followed the contours from the plans. Your braces emit "finesse". It is my desire to reduce some more mass from them. Thanks.

[TonyinNYC]

fblom,
I can't speak for Dave, but I can tell you what drives my brace shapes. If you are not familiar with the "cube rule" then here is a quick overview:
The strength of a brace is equal to the cube of its height. So a low brace would have to be three times as wide as a tall narrow brace to get the same strength. Think of it like an I-beam, the strength is still there, but the weight has been reduced by taking away the mass in between the top and bottom plate. Therefore if you make the brace taller and narrower, shape it like a bullet or a triangle, you have saved some tone-killing weight, but retained most of the strength of the brace.
Here is an article by a guy named David Wren:
http://www.wrenguitarworks.com/Workshop ... ectionTest

I remember seeing a diagram of braces done by Somogyi, but I can't find it.
Hope this helped!

Tony

[TonyinNYC]

And after writing all of that stuff above, I realized I misread your question!!

In an effort not to hijack Dave's build thread, maybe Ken Cierp can move this part of the thread and make it a new discussion?

Ken Cierp has some good info on shaping the braces on his site. Since that is where I learned how to begin shaping my braces, I see no reason why it wont work for you. Check this page, starting a bit more than half way down. He shows you how to mark off the little peaks on scalloped braces to help get a nice, sculpted look:
http://kennethmichaelguitars.com/topassembly.html

I really hope that helps!!