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Hi all,

I'm about to make my first abalone rosette, and I'm not familiar with working with that material as I have always favored wood for my rosettes. Now my customer insisted, so...

Making and inlaying the rosette is not a problem, but I'm concerned with the leveling part, once the rosette will be inlayed. I don't have a drum sander large enough to allow me to level it this way, so I'm going to have to do it by hand. And maybe I'm mistaking, but I believe I've read in past threads that it can be tricky to hand level an abalone/MOP rosette, as the softer wood around the rosette gets sanded more that the actual rosette, thus making an uneven surface once the rosette is leveled. There were also concerns with sanding dust staining the spruce around it. Is that so? And if so are there any tricks to avoid that?

Thanks!

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Don't you go be sanding that balony,

Use a scraper to take it down flush.

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Audiences and dispensations on Thursdays ~ by appointment only.


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Ah, ok. Somehow I was convinced abalone couldn't be scraped...

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

I find it's best to try and leave a minimum of shell above the surrounding wood. If you remove too much depth,
you're likely to find the shell looking very different than the original surface. So I try and remove about .005" max.
And as above, don't try and sand the shell down, the surrounding wood will cut much faster than the shell. Final
sanding in finer grades to get ready for finishing is OK, but if the shell is inlaid into dark woods the white sanding
dust needs to be carefully removed.

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Gene

Politicians and diapers must be changed often, and for the same reason- Mark Twain

Good advice, both the scraper and the file.
Another approach is to leave the shell slightly lower and completely cover the surface with CA, then you don't have to remove any shell. It does alter the appearance slightly, you'll have to test it on scrap to see if you like it. I actually prefer the look.
I originally tried it because I had some abalone and the color layers were really thin, so I wanted to avoid scraping it and ruining the colors.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Vy nice , cedar/purpleheart?

A hard scraper with a right angle edge, such as the ones StewMac sells, will hold up pretty well on shell. A harder steel than the D-2 they use on those works even better: my old scraper is M-2, steel and that holds the edge a lot longer, but it's more expensive and harder to heat treat. Or you can go tot he ultimate weapon: glass. Some folks like to keep a box of microscope slides around for this sort of thing. Big drawback: you can't sharpen them.

You do have to be careful when scraping shell not to 'washboard' or nick the surrounding wood when you get hung up in a joint. In practice, I'll scrape until I'm almost there, and then switch to a big hard block and 180 or 220 sandpaper. You do have to be sure that you're not falling off the edge of the shell and dishing the wood all around, but it's possible.

Thanks for your input guys!

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

I'm confused by the resistance to sanding. Shouldn't a hard block, 6 inches or so, be able to maintain stability relatively easily, always kept in contact with 2 parts of the rosette?

Or perhaps I'm just confused

Steve

I would simply hard block it as well if I had to do it by hand, with a piece of hard maple or baltic ply, big enough to hit half the rosette ... 150 grit and away you go

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I usually use sandpaper with a block of wood as backing. Works for me. On abalone purfling I usually use a scraper. That works also.

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Joe Beaver
Maker of Sawdust

I use a scraper and just true it up and put a burr on it as needed. Sanding things like this level with a hard block usually leads to tearing up the surrounding top as the shell will pull the abrasives off the paper and it will now roll around freely under the block and mar the top.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

On the two I've done:
Double check routing depth to ensure the shell is close to level as possible, but on the proud side.
While scraping the rosette purfling flush, I notice a little powder from the shell. Then I switch to a ROS with 120. Works fine.



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Shellac the wood before inlaying... that will keep the dust out. Then scrape level. I use a card scraper, but shell does dull it pretty quickly. Just move to using a different part of the edge, until you've used up all of it and then re-burnish.

I usually use a sort of rotating motion to scrape. Anchor one corner of the scraper, and rotate around that, to keep from scuffing the surrounding wood. I have the corners of my scraper rounded over so they don't scratch the wood.

I've never tried a file, but were going to, I'd put masking tape over the ends as a sort of depth stop, to prevent scuffing of the surrounding wood. Seems risky of chipping the shell though, if the teeth ever snag on the 90 degree edge. Also probably more dust fluffed into the air than careful scraping.

I did do abrasive leveling on a headstock once and it worked fine, aside from the dust fluffage. I used my trusty extra-extra-coarse dia-sharp stone, so no abrasive particles falling off and scratching things up. I also used the masking tape depth stop trick with this, which worked well to keep the sanding on the shell and not the wood, until it was level. Then a quick pass with the scraper to take out the sanding scratches.

A hard, large (1/2 sheet) sanding block works well for me on rosettes (shell and hardwood end grain into spruce and cedar). I have a wooden backed file (similar to a fret file) that I use on shell purling. The file wears pretty quickly though. I get about half a dozen guitars per file. An integral part of the process is the brush (or vacuum). Remove the debris after every stroke; don't "scrub".

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Scraper and file, here. I have a few files with a wood 'handle' glued to one side. Clean the file with a card scraper(why, oh why, is a little wire brush named a "card scraper"? after each stroke, and it'll last a long time. I sharpen my scraper with a file, but don't turn a hook on it for this use, and it will usually last for the duration of the job.

Why not sand? Because the shell is many times harder than the wood, and even with a hard sanding block, you'll sand away more wood than shell.

Mario: In the machine shops I worked and frequented we called them "file cards", a flat wood body with Chinese bristle brush on one side and close cut steel wire brush on the other. Yours may look a bit different.
Tom

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A person who has never made a mistake has never made anything!!!

I tried hard blocking with 80 grit once. Bad idea. It scratched up the Spruce pretty bad. I had never considered that it was from dislodged abrasives, but that was probably it.

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Pat

Here's paua abalone and Aus. blackwood into a cedar top:


Flat as, no ripples, French polish finish, levelled with sand paper on a half sheet hard block.

Here's a better pic of the whole body:

Here's paua straight into spruce (and plenty more examples, all done the same way, if you care to click through them).

Must be a technique thing. I usually start at 120 grit, Klingspor papers.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Tom, correct, "file card" is the term I wanted, but ye olde brain wasn't running at full song, I guess...

But file card is a vague and misleading term, IMO.

I've had great results with a hard maple block and quality sand paper,changing paper often and using good lighting.

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Paul Bordeaux
http://www.bordeauxinlay.com

Mario: I think the name "file CARD" comes from carding brush that is used to card wool before it is spun into yard. I'm referring to the old time methods our ancestors used. I always thought it a bit strange myself. It would seem that " file brush" would be a more suitable name.
Tom

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A person who has never made a mistake has never made anything!!!

Redwood/Bloodwood, with spalted maple as the center of a 3 piece back.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon