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for abalam inlay, in headstock, what type glues can I use?
MM

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Mike McNerney

Thin CA to hold it in place, then fill any gaps with wood dust from the head stock, flood the dust with thin CA, level and finish.
If you have big gaps, you could also use epoxy mixed with saw dust or dye depending on the head stock veneer. Ebony is an excellent wood choice for hiding inlay goofs! The fill is invisible with CA and ebony saw dust. Inlaying into light colored wood is problematic because it is very hard to hide the gaps. CA and saw dust will turn darker than the surrounding wood.

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http://www.CostaGuitars.com
PMoMC

http://www.youtube.com/watch?v=AsZuwAXcfUU
this is how I do it.
there are many ways to do it find what works for you

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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

On the first step I fully agree. Thin CA is very important for this entire operation for one simple reason: thicker varieties are formulated using additives such as fumed silica which make the cured product darker. Straight CA is perfectly clear because it literally turns into acrylic. Also, do not use any type of activator spray as it will decrease bond strength and can also make the CA more visible. On oily or acidic woods it can take much longer to cure as a result, but the wait is worth it.

I have a slight modification to offer on the sawdust and CA method. Make a nice little pile of sawdust (for finer particles I recommend making it with some 400 grit sandpaper, it take a while but seems to be worth it.) Add water dropwise and mix until the particles are held together just enough to be workable when picked up, the best way to describe this is that dust particles will no longer fall out and you should be able to roll it into a somewhat stable ball. Work this into the gaps, and I mean press/rub/massage it in as much as possible and don't worry about making it perfectly level yet. It's okay to rub off some excess, but it's a good thing to have some left over dust protruding over the top of the gap. Allow it to dry for 5 to 10 minutes, and then start going over it with the CA. It should soak into like a sponge. Give it a few minutes before repeating, and don't be surprised if it takes several passes to saturate. Next, let it sit. Even though CA often initially cures within a few minutes, the complete reaction can take a few hours to reach full hardness. The final step is sanding. If you've followed these directions correctly the resulting filler will be very hard, and I recommend taking your time in case you encounter a void (dust.) If you do, fill it in with CA and wait a least ten minutes before starting again. Aside from grain pattern, you will end up with an extremely close color match. Good enough that one a finish is applied it should be invisible.

The reason this is more effective than just rubbing in sawdust and filling with CA is that by making a slurry first, it is easier to compact so you are left with 99% wood fiber with a tiny amount of CA working as a binder. I developed this method for a manufacturer of kit guitars who routinely had about a 0.020" gap underneath their frets. Dry sawdust made the spots visible after sanding. Wet sawdust "putty" packed in so effectively that while the work was extremely visible at first... after sanding only the wood showed through. As an interesting note, on a few spots the fret tang was cut ever so slightly short. Following this filling procedure they were completely covered. It really looked beautiful with nothing but the crown visible.

Good luck, and let me know if you need any clarification.

Hugh,
Does that putty trick work with light colored woods to get a color match better than CA and saw dust?

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http://www.CostaGuitars.com
PMoMC

thanks all & Hugh you sound very authoritative so I just printed that & it's going in my guitar build binder.

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Mike McNerney

Tony-
It can vary depending on wood species, and I have a very strong but unconfirmed theory that it is related to mineral content although other factors may come into play as well. With that said, I have tested the method successfully on maple. It is also very likely that because the wood fiber is so prevalent and exposed, especially after sanding, it will accept stain. If I get a chance in the next few days I might run a couple of quick tests to verify my suspicions.

Mike-
I used to get paid to provide answers like this... So it's good to hear that I haven't lost my touch.

Hugh,
Awesome. Thanks. Next time I need to fill on a light colored wood, I will certainly give your method a try!

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http://www.CostaGuitars.com
PMoMC

I've advocated a method similar to Hugh's, but I don't use water. I use extremely fine dust and I very carefully compact it into voids and then saturate with CA. Same method without the water, with the main idea being minimum amount of glue in the fill. I only use the ultra thin CA for inlay work or any type of permanent joint.

On ebony, I have actually gotten invisible repairs (I couldn't find them again) as opposed to the 'invisible' fills most methods produce. The way I could usually find repairs is that there's a slight difference in reflectivity between fills and real wood that can be seen with the right sort of lights and angles, and with the super-dense dust fills the difference is no longer perceptible. Finishes help hide all kinds of stuff, so you can be a bit 'sloppier' on a headstock or a body than you can on a fingerboard or bridge.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services