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What’s the best way to repair and stabilize a crack like this? I have a coco commission and the guy wants me to build what I would build for myself. Figured I’d build myself one too at the same time since I probably will end up hiding it and making excuses for months not wanting to part with it lol. Just kidding of course but before I start on mine I need to get this fixed so that it doesn’t show under finish.




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I had some cracks on the cocobolo I am using right on the dark lines like that. Mine was not open and I used thin CA glue to stabilize the crack.

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I would use thin ca and hit it fast with 180 grit paper to blend in the crack with fine sawdust

After gluing it you might want to put a couple of small cleats on it.

Thin CA and 180 grit worked for me. No trace under finish.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I've hit it with CA glue and sandpaper 4-5 times and I can still see through it. Seems stable though, it might have already been filled with Epoxy. Either way I'm going to go ahead and build with it. The pin holes filled up nicely.

Is that a side? I agree with all the CA comments - works great for fixing cracks in hardwood, but I have zero experience in bending a side after fixing a crack like that. I don't know how you'd bend a side after gluing a crack like that.... My 2 cents.

Very carefully...

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

I have seen other posts referring to coco as Mexican crack wood. Seems to me it is crying to be laminated.

No it's a back, I just trimmed it to fit my mold and get material for the matching rosette. The sides seem fine but I do think some finger braces are in order if not a lamination. My last laminate sides didn't turn out so well so I built a new mold that should fix the problem. I suppose it's a good time to give it a whirl.

That would be ziricote. Cocobolo is the Mexican nasty dust wood.

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Pat

Hey now- true it's the nasty dust- but arguably unequaled in beauty and it taps pretty good too.

Kinda like would I bang (insert latest pop culture hot chick's name here) if you knew you'd get gonorrhea? Sure I would, I can get over that with a visit to the doc. But herpes? Nah. Is there a herpes of wood though? I sure hope not!

Good to know because I have one of each in the hopper.


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The best bet now is use ca solvent and compressed air to clear the fix out. Then work coco sanding dust into the crack, work it in tight, followed by thin ca and more dust.

That should do it

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Joe Beaver
Maker of Sawdust

In the long run, it might be good to make that crack structurally sound. I would put a spline of matching wood in it. I would make the crack into a V-shaped groove and fit a matching splinter into it. Then I would glue the splinter in with hot hide glue. If you work from the inside and make it structurally sound, you can then use the CA and dust fill on the outside so it will disappear. Or, you could do CA and dust fill with cleats on the inside, but someone will be able to see the cleats.

I think this is well know, but be careful with the Coco dust. I used it for a bridge plate and just the little dust that kicked up left me with a rash on all exposed skin (glad I used a mask). My hands swelled up like I had arthritis for over a week. I am thinking about using what I have left for laminated braces, but think I should invest in a hazmat suit first. I can't imagine what would happen if I inhaled it. My experience may be more extreme than most, but please be careful.
GS

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I think I'm a bit late on this.
But I would have humidified the plate till the cracked closed and then use CA or Hide Glue.
And then cleat it underneath.

[/quote]I think this is well known, but be careful with the Coco dust. I used it for a bridge plate and just the little dust that kicked up left me with a rash on all exposed skin (glad I used a mask). My hands swelled up like I had arthritis for over a week. I am thinking about using what I have left for laminated braces, but think I should invest in a hazmat suit first. I can't imagine what would happen if I inhaled it. My experience may be more extreme than most, but please be careful.
GS [/quote]

Me too - I'm extremely allergic to cocobolo.
I don't touch the stuff.

Ziricote - Mexican crack wood
Cocobolo - Poison ivy wood

So far I haven't had any issues with it. I'm thicknessed the back and sides and will be bending this week so hopefully I'm immune.

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Brad, probably not immune, just haven't developed a sensitivity to it yet.

Late too. I'd go with what Bob Gramann said. That crack looks to me like what ziricote is known for. The wood shrank--not necessarily from humidity issues--because that's what these woods do as they age, especially if it's figured. Happens with Brazilian too, just a spontaneous crack. It helps to have well-aged wood that's not from stumps. Humidifying it would probably have little to no short term effect, and less for the long term.

Pat

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formerly known around here as burbank
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Cocobolo is a sensitizer. More exposure increases your sensitivity, I don't think anyone is immune. I can still use it, but I have to minimize contact, especially with the dust. It is similar to Pao Ferro (aka morado, bolivian rosewood), which didn't bother me at all the first time I used it. Now I can't use it at all, I don't even have any scraps in the shop.

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