"Superglue" as wood hardener

[opps]

I am currently working on an exterior in Chiswick. The ends of the barge boards required a bit of timber splicing. Naturally, I removed most of the rotten timber but some areas were quite "punky". I didn't have any wood hardener with me, so used a filler knife and super glue. It seems to have worked better than the Tetrosyl wood hardener that I normally use... and the biggest advantage is that I was able to sand the timber flat after 20 minutes. Downside- I ended up with loads on my hands and it costs a lot more (that said, I only used half a bottle).

I will definitely consider using it to deal with interior MDF window boards which have been water damaged in the future- primarily because of the rapid curing time.

 

[mattylad]

When you add baking soda into it, it certainly does create a hard filler that can be sanded down and painted.
I have used this trick and it worked for me.

 

[big-all]

my thoughts on superglue

hard hard hard and no flex so expansion and contraction may in time cause cracking in the finish it could possibly also start to delaminate the glue "patch" from the soft material at the point the glue finishes and untouched wood starts
please please share how it goes warts and all in a few weeks time a years time and in many years time as it helps others learn from others experiments
and for what its worth you cannot be wrong or fail with an experiment just not the best or expected outcome hoped for but not sharing means others will make the same mistake very unessiserally

 

[^woody^]

I think I've seen all the tiktok and insta videos of this wonder-product use of CA glue and bicarb and cotton wool.

As big-all says, it's very rigid, so the longer term use in timber and flexible plastic is questionable. But admittedly all the repairs look lovely in a 30 second video.

As a hardener, I'm not sure that CA is thin enough to soak into the wood fibres, and therefore may effectively act like a varnish and stay on the peripherals - which makes a delamination risk over time greater.

Having said that, if you are aware of the limitations and risk, then it may well be appropriate for some uses. Internal on a relatively stable material like MDF in dry conditions comes to mind.