What to use to fill cracks in a newer Martin 00016-GTE?

[Jeff Perkins]

I've repaired a side crack in a Martin 00016-GTE, structurally. What would you guys use to fill in the crack? I've already sealed it with shellac. Should I use nitro or CA and scrape? Any help would be appreciated. I'm afraid of sanding or scraping through the finish. It's the satin finish.

[Greg Mirken]

Veneer? Style 16 sides are solid.

Why is there anything to fill? Pictures?

[Jeff Perkins]

I thought the sides were veneer by the look of them. But you're right. Here's a pic. Let me know what you think.

[Greg Mirken]

Too bad it wouldn't close up better. At this point I'd be tempted to leave it as is if it's structurally solid. If you start trying to repair that sprayed satin finish I fear you'd end up with a bigger, more obvious repair.

[Jeff Perkins]

That's the best I could get it closed with molds. I've sprayed aerosol satin over another 16 series before (with the same finish), and it worked just fine. I know you normally shouldn't do it, but it looked good before and I had no problems. It bonded just fine. This is the second 16 series I've had with the same problem. If it was a normal nitro finish, I wouldn't hesitate doing it traditionally. I'm not to worried about spraying over it, but the customer wants it filled in. If you had to choose, would you use nitro or CA or something completely different, maybe hide glue??

[Pierre-Antoine Roiron]

CA would be fine.

[Jeff Perkins]

Thanks, that's what I thought. That's what I used before. I was just hoping there might be something easier to work with.

[Todd Mylet]

Jeff,
I would probably choose none of those options. You want something that isn't going to shrink back much. Both CA and nitro will shrink back. And the hide glue will take quite a while to harden completely in a crack that deep. Beyond shrink back, I would ask myself what I want the fill to look like. Do I want it clear or opaque? If its clear you'll see down into the crevice which will look a little weird and you often will end up with a few suspended bubbles in your fill material as well, which will also be visible. So I would choose an opaque filler and, with a crack like yours, probably a dark color to match the darker pore filler. It will be obvious where the repair was when the touch up is complete, but it will look solid and well repaired. Since the color of Mahogany changes depending on the angle you are viewing it from, touch up beyond a solid fill is very difficult. You can do a shellac stick burn-in followed by pigment and graining and getting it looking great from one angle only to find the repair sticking out like a sore thumb from another angle. So I would color some epoxy dark brown or black and use it to fill the crack. Then level the epoxy, lightly scuff sand to 320, spray two coats of nitro, sand to 600, and spray a final coat of satin finish. The final coat can be standard nitro but I really like a Mohawk aerosol finish called Tone Finish Easy Sanding Sealer in flat sheen (product #M102-0484). It probably goes without saying that through out this process you want to avoid sanding through the existing finish because if you do you will lose the original stain. And matching the Martin stain is difficult.

[Jeff Perkins]

After tinting some epoxy and testing on scrap, I think that's the way I'm going to go. It's easier to clean up with denatured alcohol. I don't like using epoxy unless it's a last resort. But for this repair, I think it will be the best choice for the customer.

[Greg Mirken]

Todd makes good points about color matching. Anything will show; dark brown is not a bad idea. If you go with a clear CA fill, seal it with shellac before you apply any nitro or it will sink due to the solvent in the finish.

That sure is nasty looking damage.

[Kerry Krishna]

What happened to it? There are about a dozen circular smacks indentations all in almost the exact same spot. It this some kinda odd case damage or?

[Greg Mirken]

Those look like random-orbit sander scratches...

[Jeff Perkins]

The guy said it happened in the case, somehow. He wasn't really up front about it, embarassment probably. I'm not sure about those circular scratches. I wondered that myself. I think going opaque is what I'm looking for. I know all about the angle problem with mahogany looking great one way, and horrible at another angle. I know it won't be invisible, and so does he. But, I don't want a nasty crack in the finish. I'd rather it be noticeable and flush, and so does he. I've tried matching that martin stain, and it's really tough. I may try the epoxy out on some scrap mahogany and see how it looks. Thanks for all the help guys. Anything else anyone can think of would be greatly appreciated as well. Here's what it looked like before I got it. I'll add pics of it after I glued it back together later.