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I finally am at the point where I am shapping the braces on the archtop top. Seems that the top was very flexible without the braces and now is extremely stiff with them glued on. I have now shapped them somewhat trying to reduce the stiffness of the top. I have almost no tap-tone ring to speak of at this point. The node moved from the lower bought to the upper bought and the tone has a quick decay. Pryor to the braces the decay was longer and more harmonicly rich.

Brace pattern is X. I used 7/16" wide braces quarter sawn poplar (I think). Height at the X is about 5/8" at the most and then it is scaloped every 3" with the last scalope on each end about 1.5" long. Top is .250" thick down the center 3rd of the top and is about .185-.195 on the outer 2/3rds of the top per Benedetto design. F holes are oversized Grestch-Cello style.

I will take some pictures tonight to show you what it look like:

1) Do I continue to reduce the bracing in overall height or the width too?

2) Do I need to be cautious of how low the brace gets between the scalope points?

3) The braces are currently running all the way to the edge of the rim, but do not go over the gluing surface of the back. (About halfway into the recuve area) Should I shorten them to be inside the recurve?

Thanks for any tips.

Joe

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Joe

My tips may not be welcome.

1) use spruce. Why are you using poplar?

2) don't scallop. Some use a single scallop for the whole leg of the X. But IMO archtops should not be scalloped other than the end taper. Where did you get this every three inch idea?

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Sounds odd to me, too, but I'm waiting until I see the pics. One hint, though, would be to look at a violin's bass bar.

Al, some people never want to read the book. Always waiting for the picture!

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I'll post pics tonight. The scallop design was somewhat my own idea, but I saw a really nice design on the MIMF of simular bracing...except his scalops were about 1.5" tall. Mine are short.

I'll get a picture tonigh,

Joe

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Joe

Pretty sure the design you saw was Bill Moll's. It looks pretty cool and it seems to work for Bill.

Yes, you are correct. Bill Moll's bracing has extremely tall scalloped bracing.

In the end, I decided to keep working my braces, lowering the peaks on my scallops until I got back the nice tap tone. Esentailly I ended up removing the scalloped look all together to get the tap tone ringing again. So now the bracing is pretty straight/flat. I did end up quarter rounding each side of the brace though. Because I used a little wider/thicker brace than I was supposed to, I domed the top of the brace to reduce some of the mass. This also helped with the tap tone. The top is now fairly stiff, but has a tone close to what it did before I added the braces.

One thing I was surprised at was how flimsy the top got once I cut the F holes, but prior to adding the braces. The top flexed quite a bit after that. I can now see how detrimental loosing a brace on an archtop could be while the guitar is under tention of the strings.

Still learning...

Joe

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Joe