"The Natural Philosopher" wrote in message
...
On 31/10/2019 18:48, Chang wrote:


"The Natural Philosopher" wrote in message
...
On 30/10/2019 20:20, Chang wrote:


"The Natural Philosopher" wrote in message
...
On 30/10/2019 13:37, Roger Hayter wrote:
Ian Jackson wrote:

In message , Jeff Layman
writes
On 30/10/19 08:07, Ian Jackson wrote:
In message
,
writes On Wednesday, 30 October 2019
02:44:07 UTC,
Jake wrote: I poured caustic soda down my shower hole and it
has
harderned any leads ? I'm panicking water dissolves it.
Vinegar
dissolves it faster, but beware of splash
from caustic, a chemical that can blind you.

Some brands of caustic soda 'harden'. With others, there's a
rapid,
heat-producing reaction with the water, and dissolve totally
without a
trace. Why is this? Have the former been 'cut' - ie something has
added
to bulk it out (such as washing soda)?

It's probably due to the amount of water added and the complex
hydrates
sodium hydroxide forms with water, particularly the eutectic
mixtures
of varying solubility:
https://en.wikipedia.org/wiki/Sodium_hydroxide#Hydrates

"A hot water solution containing 73.1% (mass) of NaOH is an
eutectic
that solidifies at about 62.63 °C as an intimate mix of anhydrous
and
monohydrate crystals."

Thanks. I'll study that. One thing I didn't mention was that my
water is
extremely hard, and it may be the calcium that does it. However, it
does
seem that some brands of caustic soda are worse than others.

My guess would be the size and shape of the pellets and the rate of
adding water would be important factors. Aren't you supposed to
gradually add the NaOH to the water and use the solution?


That's the namby way to do it, yes, but Real Men„¢ fill the u-bend up
and pour a boiling kettle down. That shifts any fatbergs

you get superheated pure NaOH and lots of pressure.

Which might be a problem with modern plastic drain pipes.

It isn't

One end is always free

It clearly isnt if there is lots of pressure.

'lots of pressure' is relative to 'none at all'

The vigorous boiling:

- heats the fat berg
- adds pressure at the base of the accessible water column in terms of
short duration pulses.

It's a bit like a hammer drill.

It is not like a shotgun cartridge. Or pumping up a car tyre

Experience suggests that it is highly effective at dislodging congealed
fat and represents no danger to pipework and only a small danger to stupid
people who lean over to see whats going on without glasses on.


But then, I have tried it many times and you obviously have not.

I have actually, but I have earthenware pipes.

And a mate of mine, a plumber, used to be keen
on pouring a Winchester of conc nitric acid into
blocked drains and did find that worked very well.
That as in the days before plastic drain pipes too.