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Since I have a project that may benefit from having glue the same color as the neck, I searched for the subject and came up wanting. So I decided to run an experiment. I took a scrap piece of walnut, cut it in half. I colored a capful of Titebond I with some food coloring. Clamped the pieces together and left them over night. Unclamped and left them for several days. Then cinched one end in a vice and clamped a pair of vice grips on the other. I'm 170 lbs and it took a little umph to get them to break. Then I copied this with plain glue on the other ends and repeated the process. It took roughly the same amount of force to break it again. After all of the talk about the glued joint being stronger than the wood I expected the break to be rather jagged and fragmented. I was surprised to find it really separated right at the joint. There was one overlap pull on each end, but for the most part it fractured right at the joint. I'm leaning toward assuming that the food coloring didn't affect the properties of the glue. One note however, the glue was blue when it was mixed. It dried a green shade, I guess from the yellow of the glue mixing with the blue of the food coloring.

http://s735.photobucket.com/user/bushit ... ue%20Trial

Titebond has a dark colored wood glue if you need it. IME when wood is properly joined there will be no glue showing in the joint when finished so I do not see the benefit of having colored glue. After all you don't see a yellow strip down the center of a rosewood back set when they are glued together with regular titebond.

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Brian

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

https://www.howardguitarsdelaware.com/

You have to remember that I'm gluing a broken neck that will, in all likely hood, be missing small fragments at the edge of the break. I can always fill and shoot the whole neck. But I thought it would be interesting to see if I could leave the break exposed, but not with an ugly glue line showing. Just a thought. Hey, I'm still learning this stuff. But this and other forums offer the best help a person could ask for and at a better price than a weekend seminar at a luthier school. And those of us in the learning phase are forever grateful to those professionals who offer their knowledge up to us.

I think food coloring is water soluble and maybe also soluble in other solvents. Even if it matches when first glued, possibly the color will leach out in finish or from hand moisture over time. There are colorants marketed for adding to fillers and finishing products that might be more predictable. Some tinted items are colored with a mixture of pigments that could separate or react with things it contacts. I once tried to use a black magic marker over a lacquer varnish to hide some poorly filled chips on a guitar side along the binding. The marker turned transparent, fluorescent green.

Since I wrote the original post I've noticed that Stew Mac sells colored CA. It's probably the better way to go. I can just wipe a little more squeeze out at the seam and back fill with the CA. Or simply shoot the whole neck black and call it good.

If you want to color any sort of adhesive without affecting the chemistry, the best thing to use is dry artist's pigment, available online or in your local art supply store.

If you intend to use the glue to fill in some spots, i'd use clear epoxy to fill.
Epoxy dries hard and can be sanded unlike Titebond.

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wah
Wah-wah-wah-wah
Wah

Dry pigment - Great Idea!

I used some Titebond mixed with mahogany dust to fill a larger spot, then covered it with CA. The titebond had a porous surface, hence the CA. Seemed to work pretty well, but you're right, epoxy does sand nicely.