Forum: woodworking.stackexchange.com
Tags: <glue><bowl><wood-repair>
Title: How to effectively fix a crack in a turned bowl
Question: I recently came into possession of a wonderful turned maple bowl however there is one downside. There is a small crack about halfway through the bowl. The crack goes fully from top to bottom but not fully left to right. The bowl is not about to fall apart but I think after a while of putting fruit into it, or several used as a salad serving bowl the crack would spread and weaken.   Is it possible to glue this and (bonus points) glue it with a food safe glue?

Answers:
sents: text: I suspect that it actually isn't going to get any worse.
text: However, what is generally accepted practice is to use epoxy.
text: If you want to hide the crack and patch you can mix in some sawdust, in this case maple sawdust would be best.
text: As an alternative, you could mix in some other colorful stuff to make it pop.
text: Ground turquoise is a common choice for this.
text: Of course any glue or epoxy will leave a bit of a mess and will need to be cleaned up.
text: You might end up needing to refinishing the whole piece.
text: If that is the case, nut oils are food safe and so is carnuba wax, which is hypoallergenic.
answer_details: author: woodworking.stackexchange.com/users/27/bowlturner
score: 7
sents: text: If it were mine, I think I'd either try a tinted epoxy or epoxy-based filler.
text: Or I'd accept the crack but stabilize it with a butterfly inlay... or just accept the crack as part of the character of the piece.
answer_details: author: woodworking.stackexchange.com/users/91/keshlam
score: 4
sents: text: Frank Howarth made a great video about how he "repaired" a cracked wooden bowl.
text: The rough turned maple bowl that I wanted to finish next had cracked.
text: The crack was at an angle to vertical when the bowl was sitting normally.
text: I cut out the section of the bowl with the crack on the band saw.
text: Then I build a new segmented piece to take the place of the section.
text: In this new section, I continue the idea of the chevron pattern, and add more detail.
text: I give the chevron pattern branches by adding alternating pieces of birch and walnut wood on either side of the pattern.
text: I also add a walnut ring at the top of the bowl so the segmented pattern has something to die into.
text: Then I turn the whole bowl down to a finished piece.
text: He made a feature out of it
text: You'd have to be ambitious to do what he did
text: but it might serve as inspiration.
answer_details: author: woodworking.stackexchange.com/users/158/RedGrittyBrick
score: 4
sents: text: Due to the size of the crack a mechanical repair would be best like the aforementioned butterfly or stitch inlay or in lieu of that an epoxy would work.
text: I wouldn't try to color match with dust or pigment as it just plain won't match and may just become an eye sore.
text: If you want to color it go with black or some sort of metallic mix.
text: CA glue, aka super glue, probably won't work here
text: - it's too large of a crack.
text: I wouldn't do it on my bowl.
text: Filling it with gap filling or thick CA will probably result in a mess, also CA glue is brittle while epoxy can flex a little bit with seasonal movement.
text: I use CA glue for hairline cracks, not open, through cracks.
text: And you would never clamp this back into place
text: - there is a reason it split in the first place so don't force it back.
text: (Shrinkage, seasonal movement, too close to pith, internal stresses, etc)
text: For the epoxy generally almost any two part epoxy would do.
text: Using blue tape, tape off one side of the crack so it doesn't just spill out all over.
text: and fill.
text: After dry remove tape and sand bowl or at least the local area and refinish with mineral oil, wax or a combo of those or walnut oil.
text: Boom you're done.
answer_details: author: woodworking.stackexchange.com/users/2401/user2401
score: 2
sents: text: Since the surface would need to be cleaned up manually (not on a lathe), try CA glue and clamp it together.
text: Much less mess than epoxy to clean up.
text: The CA glue will be safe after fully curing.
answer_details: author: woodworking.stackexchange.com/users/265/OSU55
score: 1
sents: text: Not enough rep to add a comment but most glues are food safe when dry.
text: The drying agents may have toxins in them but they evaporate and the dried glue is okay.
text: Obviously you'll want a glue that's waterproof when dry such as Titebond III
text: The Wood Whisperer has a good post on this
answer_details: author: woodworking.stackexchange.com/users/105/Dano0430
score: 1
sents: text: You might want to get the "gap-filling" variety of CA.
text: It's nice and runny and should seep nicely into the void without a lot of coaxing and, of course, as the name suggests, it will fill the gap.
text: Personally, I wouldn't bother with clamping which will just put undue stress on the glue.
text: If this crack had been in the bowl when the turner was making it, he/she would certainly have patched it in this very manner.
text: It probably developed after the wood continued to age/dry-out after the finish was completed.
text: You are just trying to get something to patch the opening.
text: You can find it at the big name woodworking stores and online.
answer_details: author: woodworking.stackexchange.com/users/380/Ast Pace
score: 0

Summary of the answers:
It is generally accepted practice to use an epoxy or epoxy-based filler to mend cracks in turned items. Other glues may also be used.
The accepted practice would be to use epoxy or an epoxy-based filler. Almost any two-part epoxy would be suitable and would flex slightly with seasonal changes. However, a mechanical repair would be best, but epoxy would work. Waterproof CA glue is also an option, but a gap-filling variety would be recommended. Most glues are food-safe when dry.