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Ooops? Top too thin?
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=21530		 Page 1 of 1
Author:  Frei [ Thu Mar 19, 2009 12:06 am ]
Post subject:  Ooops? Top too thin?
I have a Sitka top I got for a class, and thinned it yesterday with a thickness sander. Its a beginner Sitka from LMI, and when it was at .118, we ran it through the sander and it ended up at around .111. :oops: I can bend it in an elongated "S" Shape, and that worries me, as I thought it was a bit floopy to begin with. Ill try to post a pic, but is that level of bending, elongated S, too floppy, in your opinion? Pic on Thursday.

My adi tops are really stiff and tight, thats the good news, so I may just brace this one for practice if its a dud.
Author:  meddlingfool [ Thu Mar 19, 2009 12:35 am ]
Post subject:  Re: Ooops? Top too thin?
I have less experience than many here, but I take Sitka tops to .110 as a general rule.. I would think you're all right. I also think that .110 is where a lot of factory folk take their sitka to as a final target dimension, and the general vibe I get is that many handbuild people think factory folk 'overbuild'. Ergo, if you're starting from where 'overbuilt' starts, you ought to be OK. My humble opinion.
Author:  John Hale [ Thu Mar 19, 2009 4:50 am ]
Post subject:  Re: Ooops? Top too thin?
My first top way way to thin I many here said I'd be better starting again, Mike Collins suggested a thicker bridge patch to me and carry on and it's the best thing I've done it sounds fantastic

John
Author:  woody b [ Thu Mar 19, 2009 5:47 am ]
Post subject:  Re: Ooops? Top too thin?
I doubt it's too thin. Most people make their first tops too thick. Hold it by the edges, (not the ends) and shake it. It should....resonate, kinda like a piece of sheet metal. If it doesn't make any sound, and doesn't "flop" it's too thick. If it just shakes/flops but doesn't really make any sound it's too thin. Don't worry about the measurements, just make it feel and sound right.
Author:  Martin Turner [ Thu Mar 19, 2009 6:03 am ]
Post subject:  Re: Ooops? Top too thin?
My sitka steel string tops are usually around 0.125" around the bridge area but graduate to as little as 0.085" around the edges. Each top is different and finalthickness is judged by flexing the top regularly while doing final thicknessing with a cabinet scraper.
Author:  David Newton [ Thu Mar 19, 2009 8:52 am ]
Post subject:  Re: Ooops? Top too thin?
Frei.
You didn't say what guitar this top is for, if it is a dread or other large guitar, .111 is probably too thin to start with, especially if it is floppy, as you say. You could save it for a small guitar.
I start at .125 for large guitars, even stiff wood, then thin as I'm working.
Author:  Michael Dale Payne [ Thu Mar 19, 2009 9:04 am ]
Post subject:  Re: Ooops? Top too thin?
I can't hardly conceive that .110" would be so floppy even for Sitka most of my Sitka SJs' and OMs' were around .115-.110 I would not give up on the top till I had it braced. Did you mic its thickness more than just at the edge? How was it thinned? for me a lot more information is needed to assume the top is too thin. I have build several spruce guitars that were .095" that were great guitars and still going strong.
Author:  Lars Stahl [ Thu Mar 19, 2009 9:29 am ]
Post subject:  Re: Ooops? Top too thin?
Frei. if your worried its to floppy, then perhaps you should try and brace it with a double X pattern ! it will stiffen it up alot.

Lars
Author:  Bruce Dickey [ Thu Mar 19, 2009 11:31 am ]
Post subject:  Re: Ooops? Top too thin?
Sitka varies a lot.

I have some that is floppy as mentioned here.

I have some that is great tonewood and stiff.

Needless to say I don't buy from the rubber sitka supplier anymore, they should know better.
Author:  charliewood [ Thu Mar 19, 2009 2:34 pm ]
Post subject:  Re: Ooops? Top too thin?
Im a little concerned that I thinned a bearclaw englemann top too thin also - its around .095 in the center and thins to about .85 on the edges,, its for an Antes parlour, Im thickening the bridgeplate, using some slightly beefier kerfed linings I made specifically for the error, and Im saying what the heck.... and forging on with it

I figure if it sucks I guess Ill be getting a crash course in top replacement! It makes me cry to think of replacing it - on account of all the top work that will need to be redone?
No - on account of how incredibly frustrating it was to get the rosette just right on this one!
I dont think Ill be using englemann too much in the future unless its specifically requested, I dont like how flubby it seems compared to sitka and lutz... its also a bear to keep un-dinged and clean, especially when theres ebony in the rosette!
Anyhow I have a really old parlour made by a luthier named Joseph Obrecht - his top is thin, .90 - so Im hoping it will work out!
Good Luck
Cheers
Charlie
Author:  John Mayes [ Thu Mar 19, 2009 4:06 pm ]
Post subject:  Re: Ooops? Top too thin?
I've had sitka tops that were stiff as heck at .100 and some that were unacceptable at .125. If the top is really floppy then I wouldn't use it. You're just asking for either a muddy sounding guitar or one that the top bellies like crazy. It all starts with quality materials. A stiff top, in my opinion, is an absolute must have.
Author:  Frei [ Thu Mar 19, 2009 4:17 pm ]
Post subject:  Re: Ooops? Top too thin?
Thanks John, yea, Im not happy, there are too many low grade STIFF tops out there for the effort it takes me to build one. I can use this for center seam. I should post a picture of how flexible it is (I can make an "elongated" S with it. Im sure beefing up the braces a bit, and bridgeplate would help, but life is too short! [uncle]
Its a student top so lesson learned... laughing6-hehe
So Adi it is. This will be my third braced top, so hopefully I learned something there.
Author:  John Mayes [ Thu Mar 19, 2009 4:30 pm ]
Post subject:  Re: Ooops? Top too thin?
Frei wrote:
Thanks John, yea, Im not happy, there are too many low grade STIFF tops out there for the effort it takes me to build one. I can use this for center seam. I should post a picture of how flexible it is (I can make an "elongated" S with it. Im sure beefing up the braces a bit, and bridgeplate would help, but life is too short! [uncle]
Its a student top so lesson learned... laughing6-hehe
So Adi it is. This will be my third braced top, so hopefully I learned something there.


Glad to hear it. Good attitude too. Take it as a learning experience and move along. These learning experiances are way more valuable than the cost of a top.
Author:  Bruce Dickey [ Thu Mar 19, 2009 8:38 pm ]
Post subject:  Re: Ooops? Top too thin?
Thanks John.

Now I know what to do with my floppy tops.
Center Seam material.

Great thread.
Author:  LaurieW [ Fri Mar 20, 2009 6:11 pm ]
Post subject:  Re: Ooops? Top too thin?
You guys are discouraging me! I have a white spruce top that paid the price in a battle with a drum sander. It's about 110 thou but quite floppy. It's master grade, I paid $100 for it, I would hate to cut it up for center strips....but it may end up that way.

It may be a good time to check those deflection measurements I hear people talk about.

Maybe there's a market out there for master grade center strips:D

Laurie
Author:  Frei [ Fri Mar 20, 2009 6:29 pm ]
Post subject:  Re: Ooops? Top too thin?
Laurie, can you bend it in an 'S' shape? For that price, you may want to beef up the X, and the bridge plate, and go for it. My top was a $15.00 student grade sitka. There is plenty of student grade adi and carpathian out there for $10.00-$20.00 a set.
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