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I have a small gap (< 1/32") between my tail graft (maple burl) and binding (koa) that I want to fill with burl sawdust. What glue will allow for the best color match on a lighter color wood? I've tried CA, but it seems to leave a dark-ish line. LMI white seems better, but the gap is still somewhat noticeable. Do people use HHG or fish glue? Are there any standard proportions of glue to dust that work best?

Any advice would be greatly appreciated.

John

I've never had much luck doing glue-and-sawdust, no matter what glue I try. It's always darker than the surrounding wood, in my hands.
The options are a bit limited :
a) put in some sort of filler and 'push on'
b) extend the gap so that you can put in a veneer strip (and this usually involves doing the 'other side' as well, so it looks deliberate)
c) re-do

If the guitar is for yourself, only you can decide how irritating you will find option a).
If the guitar is going to leave your hands, I'd recommend b) or c).

Cheers
John

Yes, from your description, I take that the maple end-graft is too short and not butting against the koa binding... That's too bad. Koa usually takes very well to CA and Sawdust, the resulting slurry being darker but it can still pass for darker veining in the wood... However, not if the line is a perfect 1/32 throughout the width of the piece...

Like John said, it's either filler or re-do. Maybe you can try grafting some slivers of maple in there, minimizing the filler needed. Mind you, maple is very unforgiving.

I had some considerable router tear near and end-graft once. It was Cuban Hog. I cut slivers and glued them in place with HHG. Then I filled the rest with Shellac and Pumice when it was pore filling time. Luckily for me, it was on the side so I was working along the grain. The resulting fix is invisible. However, you're probably working perpendicular to the grain...

Good luck!

Edit: Also, the closest color match you'll get in pale woods is with Pumice. Shellac the area with the palest you can find (blond) and using a 'muneca', push your slurry from the graft into the offensive gap... color wise, you can't get any better because the pumice actually digs up mini particles of the wood you're using.

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

replacing a tail graft is pretty easy to do. Sometimes you gotta bite the bullet and repair it rather than hiding it.

You can do it like this: http://mayesguitars.com/index.php?optio ... &Itemid=48

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John Mayes
http://www.mayesluthier.com

Like John says, however if you choice is "a"...well then besides glue
and sawdust may me most humbly suggest a coat of shellac
and shoving in some good old quick and dirty coloured to match





blessings
Padma

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Audiences and dispensations on Thursdays ~ by appointment only.


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The violin maker's traditional filler for spruce and maple is lycopodium; the spores, if I remember correctly, of a moss.

I'd been looking for some for years, and finally located a supplier right after the Sept. 11 attacks; Kremer pigments in New York. The problem was that it seemed an inopportune time to be ordering an air-dispersable biologically active off-white powder through the mail (can you say
'anthrax'?).

Fortunately it's a pharmaceutical, and one of my students was able to order some through a friendly druggist. Not knowing any better, he got a pound, which turned out to be about a gallon. That's several lifetime supplies for an individual luthier. My students have been taking it off my hands, though.

In use, you mix it with HHG (of course) to make a putty, and it dries to about the same color as spruce or maple. Under a coloerd varnish it's invisible, and even under clear it's pretty hard to see.

Alan: As usual,interesting and useful info. Thanks.
Tom

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

Can you sell us a gram or 2 ?

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I've used lycopodium for some years now, I use it mixed with HHG for some restoration work on historic instruments, I too get mine from Kremer, but in my case from the German head office. I bought a 100g about five years ago for €5 which I'm not a tenth of the way through, so it should last my lifetime.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

I'm not sure about the biological activity, but lycopodium is quite flammable/explosive. In the science teaching biz, it's a favorite for demonstrating dust explosions, so best to be careful about it around the shop. (If you know a sci teacher who works in a school that still has a chemical storeroom, you could probably be given a small quantity....)
Too bad I didn't know it had an application to luthierie when I had the keys to the store!

http://en.wikipedia.org/wiki/Lycopodium_powder

Cheers
John

I emailed my favorite 'weird finishing chemicals' supplier asking if they carry lycopodium powder...
Good supplier, BTW....

Quote:
John,

Yes we do. The prices are as follows:

$7.90/1 oz
$22.10/4 oz
$36.80/8 oz
$61.30/1 lb

Regards,
Dale Przybyl
WoodFinishing Enterprises
1729 N 68th Street
Wauwatosa, WI 53213
woodfin@woodfinishingenterprises.com

End quote

Thanks for all the suggestions and advice. The graft is maple burl, so there is some variegation in color. I think I'll first try grafting in a sliver that matches as best as I can find and see how it looks. If it's still too obvious, out comes the router.

John

Lycopodium is also known as ''dragons breath' and is sold to the magician folk. Usually HHG gives the best colour match but experiment with other types to see which gives the desired result. It won't be perfect though. I should know - I've used tons of the stuff!

Found a place called Schoolmasters Science that has 100g of lab grade lycopodium for $10.40....that should last a while.

They have some interesting stuff, and since the shipping is $10 minimum, you may want to browse their site for other items.

http://www.schoolmasters.com/categories ... c3&details

Thanks for the link Alan.

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