Super Glue

[Grumpy John]

Hi everyone,
I'm new to woodturning and was told that super glue can be used to repair cracks in timber. Are there any limitations as to size of cracks (okay, okay I'm bound to get some smart a#$se comments) that can be repaired this way? Also do you have to treat the timber with any cleanser like acetone etc.?

GJ

[Skew ChiDAMN!!]

I'm new to woodturning and was told that super glue can be used to repair cracks in timber. Are there any limitations as to size of cracks (okay, okay I'm bound to get some smart a#$se comments) that can be repaired this way? Also do you have to treat the timber with any cleanser like acetone etc.?

Hi John, welcome to the BB.

Cracks, yes. If by "cracks" you mean hairline fractures that can be pushed together again without gaps. Any length can be repaired this way, providing care is taken turning the result.

Personally, if the wood's cracked before turning I either won't use it or plan to turn the cracks out. I do use it when the piece cracks while turning, keeping in mind that it tends to darken/discolour the wood along the crack. I don't treat the timber.

If by cracks you mean crevices with a gap then generally the answer is no. Sorry.

[DavidG]

Thin superglue can fix hairline to small cracks.
Beyond that you need to fill the crack with sawdust then add the glue.

I have successfully filled 1cm grub holes using coarse saw dust and super glue to make it look like the original grub processed wood.

The cheap shop pack of 6 tubes of 3gm (not 2gm) do work well on reasonable cracks but for really fine cracks in good wood get the thin superglue from Car....tec or such other place. It gets in to the fine crack better.

[Cliff Rogers]

Yeah, mixed results... I find that it is good mixed with sawdust as a filler holes but sometimes it doesn't hide the crack.

[Wood Butcher]

I turned a mallet out of an apple tree. There were cracks about 1mm wide while i was turning it and all i did was flood the crack with super glue then push sawdust in. I just kept doing this with all of the cracks until the super glue stopped flowing out the other side. Finished the mallet and have been using it for three years nows without any problems.

Cheers
Rowan

[Tornatus]

On the advice of some of the old hands in my club, I have used superglue not so much as a repair agent, but to reinforce hairline cracks in locations where they might compromise the integrity of the piece during further turning - like the edge of a bowl. Recently, I was turning and carving a handle for a walking stick from a piece of yellow box burl, and I filled small inclusions in the burl, revealed by the shaping, with sanding dust, then flooded them with superglue. This stabilized them nicely and added to the figure in the piece.

I always use a quality superglue - NOT your nasty $2 Bunny's special - and one of the thinnest consistency available, to encourage it to "wick in" to the crack by capillary action. Avoid the thick or gel types - they are not gap-fillers.

Having said all that, I have recently heard and read evidence that cyanoacrilate can't be relied upon in the long term - it becomes brittle and breaks down, some formulations quicker than others. I'm told 10 years is the maximum you should expect even the good stuff to last, which means it's probably not a good idea to use it on your gallery-quality masterpieces, or anything that will see hard use. The experts tell me that 2-part epoxy is still the strongest and most reliable bond - but others may have better suggestions.

PS If you do use superglue, be very wary of the fumes, especially if you flood a crack - they can attack your eyes and mucous membranes if you are leaning too close to the action.

[DavidG]

Cliff

but sometimes it doesn't hide the crack.

Fill it and blacken it. It is then a feature and adds to the price.

[Grumpy John]

Thanks for the help fellas. Amazing not one wise crack anywhere.

Cheers
GJ

[DavidG]

Thought about it but didn't want to fracture the post.

[maglite]

Did you know that "superglue" as we know it was first used as a field treatment of gunshot victims in the Vietnam War.

Believe it or not.

[Cliff Rogers]

Cliff

Fill it and blacken it. It is then a feature and adds to the price.

Yeah well if the the piece will stand that sort of treatment, I don't even bother filling it, I just get stuck into it with a pyrography tip.

[Kev Y.]

I turned a mallet out of an apple tree.

Thats one big mallet :eek: :eek:

[DavidG]

Thats one big mallet :eek: :eek:

Or a lot of tooth picks.

[gatiep]

All the above.

I do use the thin superglue for arresting fine cracks and also for reinforcing timber like cross grained pen blanks or corn cobs for pen turning.
I use the medium viscosity for filling gaps together with the sanding dust. It does take a bit of patience but surely beats waiting for normal white or yellow glue to dry. I have used the thin whenever I threaded wood either on the lathe or with a tap and die, to bind the fibres together and harden the thread. I have mounted 20 cc model aircraft engines by drilling and tapping the 6 mm ply firewall and treating with superglue. Then re-tap the hole again to clean the threads. Four 6 mm bolts to hold the engine on the fire wall through the threadded ply holes with no other form of nut, never gave up on the job.

It does tend to discolour the wood, which often can be used as a feature.
Be careful when switching on the lathe after using the superglue because it may appear set, but can still be flung out into your eyes etc if not properly cured. Sanding it even after it has cured for a few minutes will cause a lot of nasty fumes, so use good ventilation like a fan on the woork.

Superglue is brittle, doesn't like acetone, sets like rock when wet with water and will degrade over time, which in woodturning is accelerated by the oils in the timber. However if it lasts 10 years I'll be happy as I won't make a gallery piece out of cracked wood anyway.

The 56 ml bottles from the guys in blue, trade name Hotstuff, has been around for many years and really work well. To prolong the shelf life after the seal has been broken, I keep it in a capped wide mouth glass jar in the fridge door. The glass jar stops odours from getting into the fridge ( although it is my shop fridge ) and keeps the superglue container dry which is very important as moisture kicks superglue off.

The superglue used in medical procedures, even orthopedic procedures, is a higher quality and sterile grade.

[gatiep]

Nice to see thiat this thread has not gone silly like most do lately. Keep up the restraint guys. Well done!