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PostPosted: Sat Feb 07, 2009 1:14 pm 
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I'm testing the fit for a rosette for my next bandura. It should be noted that a bandura rosette is typically continuous because there's no FB extension to hide gaps.

The pattern is BWB Ab BWB wood BWB Ab BWB The BWB are made with black and white ABS strips from stew mac, wood will be koa and the Ab is those zip abalam thingies.

The plan was to cut each piece to size from the inside to the outside, staggering the splices around the circumference of the rosette to help conceal them, putting pieces into place as I get to them then flooding the whole thing with CA.

I'm running a test and am very worried that my plan sounds great but in practice, nothing will work and my sizes might be off. I'm using a Jasper circle cutter jig so I have increments of 1/32" radius. Because I don't want to cut my pieces to size yet, I'm testing only half the rosette in this test board. I'm suspecting now that this half test might not tell me enough about final sizing and whether my channel is sized correctly.

I'm wondering if anyone has any advice on how to implement this rosette or if my sizes are off a bit, how I'll be able to tune it up to make it look nice.

Attached are two pics, one a close up and another a zoomed out shot of my test setup.

Any advice appreciated.


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PostPosted: Sat Feb 07, 2009 1:37 pm 
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It's beautiful.

Personally I'd work inside out and get each of the rings cut to exact size then move on to the next one. I've used very thin double stick material to hold pieces like this together. So once you get the inside set, you double stick it into place. Then do do the next ring, then double stick it into place, and so outward. Once they are all done, they are all perfectly sized. You then clean them off and put them in for real. Have a big workspace so you can keep each ring in order as you clean them. Then with a huge amount of patience, put it all together for the glueup.

Deep breathe, calm and go for it.

I agree with staggering the joints also you might want to see if you can cut them on a diagonal.


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PostPosted: Sat Feb 07, 2009 2:09 pm 
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I don't know if thats what Joe meant about cutting it diagonally, but you could taper your purfling to zero (height wise) on a given length, then when you wrap around, the other end of the purfling would get up on that slope and all you would have to do is scrape off the excess and you would have a seemless joint.

like so:


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PostPosted: Sat Feb 07, 2009 2:33 pm 
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Brilliant!

I had actually used that method before to repair a purfling on my last bandura where I mucked up a spot but completely forgot about it. The repair is virtually invisible.

I think that with that technique things would work out pretty well and the sizing of the purfling strips is almost irrelevant. I could probably even do that with the Ab too.

Thanks!

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PostPosted: Sat Feb 07, 2009 2:38 pm 
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What you are experiencing is EXACTLY why I put the wood ring in first, and glue it. Then cut channels to fit the shell/teflon filler and its lines separately. You can get the shell/lines to fit snug into their own channels. I dont/wont really do rosettes any other way now.

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PostPosted: Sat Feb 07, 2009 3:55 pm 
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Hi Andy, you didn´t happen to see the one I did before starting on yours ;) :D . look like its gonna be a beautiful rosette !!

Lars.


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PostPosted: Sat Feb 07, 2009 5:50 pm 
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TonyKarol wrote:
What you are experiencing is EXACTLY why I put the wood ring in first, and glue it. Then cut channels to fit the shell/teflon filler and its lines separately. You can get the shell/lines to fit snug into their own channels. I dont/wont really do rosettes any other way now.


That's a dynamite idea Tony. Thanks!
TJK

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PostPosted: Sat Feb 07, 2009 6:46 pm 
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I saw a guy named Todd in another forum overlap his binding on the side like that and come back with a flush trim bit and clean it up.


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PostPosted: Sat Feb 07, 2009 9:12 pm 
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Lars Stahl wrote:
Hi Andy, you didn´t happen to see the one I did before starting on yours ;) :D . look like its gonna be a beautiful rosette !!

Lars.


Lars,

Yes, I did see your rosette and it looks fantastic. I actually had the idea for it when I bought the zip-abalamwhatevertheheckit'scalled and when I saw yours I was very encouraged that mine would look great too.

I also like Tony's idea. I'll try a test either tomorrow or the day after but I'm already pretty sure that's the way to go. That combined with the lapped (or whatever the heck it's called) purfling should make it really nice.

The only thing left on my mind is the wood: I've got a nice piece of koa sitting around but the bridge will be walnut. The koa may be totally overshadowed by walnut so perhaps I should do walnut for the rosette too. I did walnut on the last instrument I made though so part of me wants to do something different.

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PostPosted: Sat Feb 07, 2009 10:59 pm 
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oli-lgw wrote:
I don't know if thats what Joe meant about cutting it diagonally, but you could taper your purfling to zero (height wise) on a given length, then when you wrap around, the other end of the purfling would get up on that slope and all you would have to do is scrape off the excess and you would have a seemless joint.

like so:


That's what I had in mind, not quite so much of a taper, but that's a great image.


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PostPosted: Mon Feb 09, 2009 7:34 pm 
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I decided to buy the Wells-Karol jig to help fine tune the process. I'll be doing the 'wood first' thing that Tony suggested.

One final question.

My top is jointed but I still need to run it through the sander to clean up the joints (there are two) on the top and bottom. Because the top is a little on the thin side already, I'm planning on running it through after I get the rosette in. Does anyone think I'll have any issues doing this, there being Ab inlaid in there and all?

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PostPosted: Mon Feb 09, 2009 8:53 pm 
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No help here but I sure do like the look of that!

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