Re:
It's all by its scientific name Sodium Hydroxide. I use and handle it all the time. Yes it's in most soap but that's neutralised to some extent by other things.
It is also used to neutralise Hydrochloric acid which is used to strip the white stuff of Oranges and all sorts.
But it's irrelevant in this context and so is using it for drains.
Your adding aluminium and aluminium oxide to a warm sodium hydroxide mix. It's warm already, as just adding it to water generates a lot of heat. Then adding aluminium creates a vast bubbling as hydrogen is created (so I would advise not having a fag nearby ;-) )
The hotter the liquid the faster it works.
You should never really add water to the solid as it can eject itself and that's never a good idea.
For anyone thinking of using it often, get some citric acid and cat litter while your at it.Cat litter is an excellent cheap absorbent for mopping up spills of it, while citric acid can be used to neutralise spills etc.
Anyway safety talk, now it's been screwed up, look at fitting helicoils to create a new thread to bolt in to.
According to this
8xO.75mm is the chainring bolt standard
http://www.parktool.com/blog/repair-hel ... d-concepts
Or perhaps some threadlock my fill the small gap, but not sure if I would risk it.
Live and learn and good for others to take note