DIY 'gap filler putty'. Superglue & baking soda technique, modified.

I thought I'd share a simple DIY thing I learned how to do.
superglue+baking soda is a commonly known technique, but it doesn't work so well for filling vertical spaces/holes where you can't get backing etc since you're working with a powder.

My #8 wired solution was to add a drop of two of water to the baking soda so it becomes formable like wet sand, so you can pack it into holes in the wall or any other cavity or gap you need to fill that'd be easier with a barely-wet paste than a powder. Wait for it to dry thoroughly and apply superglue to get a hard and relatively durable DIY filler. Probably not as good as something you'd buy from Mitre 10, but most houses have superglue and baking soda.

"When you mix super glue and baking soda, it accelerates the curing process. Chemically, the bicarbonate molecules in baking soda react with cyanoacrylate to create a reactive ion that more easily bonds with other cyanoacrylate molecules. These bonds establish long, polymer chains that are stronger and more resilient than cyanoacrylate-water bonding. The resultant substance is a super glue and baking soda plastic with a cement-like consistency that creates stronger, exceptionally durable bonds."

I've used it before to fill holes in the wall by packing it with scrunched up newspaper, then a sheet of cardboard in front (you can use your backing of choice, maybe expanding foam). The baking soda paste packs into the hole nicely. Once it's dry I start from the top with superglue and work my way down. It cures very quickly. Sand it after a minute or two. It should be drillable and sandable.

Wear gloves or be careful not to get it on your hands, or you could have rocks for hands.
Baking soda + superglue is a lot tougher than superglue alone.

Here's a video of other uses for it.
Don't do the one at the end, the one with the power plug, that can't be safe.

It's probably not good for it to be exposed to water over the long term, so I only use it for indoor projects.