Koa and Paua

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Bob Gleason
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Koa and Paua

Post by Bob Gleason »

Seems like supply chain issues are affecting everything including lutherie. Finally received a new shipment of Paua shell after a long wait. Photo is Paua purfling done today, but not cleaned up. Shell purfling is fast and fun, and has a huge impact on sales price.
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tippie53
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Re: Koa and Paua

Post by tippie53 »

classy
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Kevin Sjostrand
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Re: Koa and Paua

Post by Kevin Sjostrand »

Its beautiful Bob. The abalone always stands out so nicely on Koa.
The Paua has gotten so expensive now. I still have some of the laminated stuff that works well as long as you don't have to sand it, but it seems you can only get it out of China now days.
Stray Feathers
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Re: Koa and Paua

Post by Stray Feathers »

I always think of this as too big a challenge, and then I see an example like yours, and start to think about it again. Bob, did you use pre-cut pieces, or cut your own for the curves?
Bob Gleason
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Re: Koa and Paua

Post by Bob Gleason »

In the attached photos there is a pic of the uke I posted yesterday and cleaned up a bit today. BTW, I know nothing about using plastic binding or purfling. With the exception of an ocassional repair job, I last used it maybe 40 years ago. Whatever I have to say applies only to the wood bindings and purflings I use.

I use solid shell strips . I seldom use any laminated shell, though environmentally speaking it is probably better to use that. I just have had issues with some sand throughs and loss of color with laminated shell. I have only used it for special inlay issues. I have a Fish & Game Import Export License and I import shell to sell to local builders, though I don't try to compete with other suppliers like Rescue Pearl. Basically I do it to make my own shell a bit cheaper.For purfling I bring in straight strips and curved strips in a couple of radiuses.The different radiuses allow me to do any shape of purfling or rosette. I only use 76.2mm radius, 125mm radius, and straight strips.Solid shell strips are only about an inch long, so it takes quite a few pieces to do a guitar. It is not a difficult process, just takes time. Actually, shell purfling is more forgiving than just doing purfling lines. If there are small spaces in the purfling, they just dissappear in the shell. Once you get the hang of it, it is very easy. With solid shell I can do a guitar top in a little more that 1 hour. With long laminate pieces, which come in very long strips, you could probably do the purfling in half the time wihile holding your morning coffee in one hand! That is with everything prepped and ready to go of course. The only thing you can do wrong with solid shell is to not break the strips often enough. It is called cracking the shell and it makes the shell pieces conform better to the curves of the instrument. With Paua I just break the pieces with my fingers and match the broken ends together in the groove. Normally a 1" piece only gets broken in 2. No need to file the ends flat, in fact it is bad to do that. A good book that talks about this is Pearl Inlay by Patterson. It is old, but fairly complete. The only thing missing in the book is our modern favorite super glue. Attached is a photo of straight solid shell strips and another one showing a .050 thick laminate sheet and solid shell blanks. The fact that they can make the laminate out of real shell is mind boggling to me.

While I buy most of my shell strips already cut to a radius, I do sometimes cut custom rosette sizes. There is an attached photo of one I cut that is about 1/4" wide. I cut it from solid shell blanks. That is easily done on the bandsaw. The Patterson book has instructions for making a radius jig. His was made of aluminum. I cobbled one up out of wood and have been using it for more than 30 years. I use the finest tooth 1/8" blade the I can find.


Doing shell purfling is realtively mindless. Rosettes are another story. On a softwood top (hardwood tops are no problem), the endgrain of the top is already sealed by the purfling strip that you install between the shell and the top. The shell is usually inserted after you pull out the teflon strip that you used in the purfling lay-up and the glue is dry. On a rosette, the shell is usually installed along with the purfling, all 1 time. You can destroy a softwood top in an instant by not sealing the endgrain of the rosette channel. The superglue can, often does, seep into the endgrain of the top and permanently stain it. Spruce is bad, but redwood and cedar stain terribly. You will find yourself uttering your favorite 4 letter word, like dang, or in my case some other word that John would have to censor! Even a sunburst won't hide the stain usually. John has his technique for sealing the rosette and maybe he will respond. Most builders will tell you they use shellac to seal the endgrain. Does not work for me. I've tried too many times. I have had success with thinly applied poly glue and I often use epoxy on redwwod tops. Both are a PITA.
The takeaway message is that shell purfling is not difficult, and not that expensive for the effect you get. Personally I can't stand u-Tube, but I bet you can find some complete tutorials on shell purfling there.
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Diane Kauffmds
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Re: Koa and Paua

Post by Diane Kauffmds »

That's really beautiful. Yes, the supply chain has been severely affected. You're right about sealing those channels. You'll quickly ruin any soft wood, as well as maple and mahogany, if you don't thoroughly seal rosette, purfling, binding, backstrip, and inlay, channels. I wash them 3x with a 1# cut of shellac. I may go overboard with the wash coats, but after you've messed up a beautiful top one time, one becomes rather paranoid about sealing for endgrain.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
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