On Sun, 06 Nov 2005 05:02:49 -0800, Aidan wrote:


Andrew Gabriel wrote:

Year of manufacture Expected lifetime
1958 42 years
1964 20 years
1970 10 years

It would seem the industry cleverly worked out how to
turn radiators into consumables throughout the 1960's,
and create the need for inhibitor (another consumable).

Active/acidic flux wasn't widely used, probably until sometime around
the '70s (?). Until then you had to use a passive flux and thoroughly
clean the pipe and fittings before soldering. A couple of old-timers
have told me that the raging corrosion, and the need for power flushing
to shift corrosion products obstructing the pipes, is something that
they rarely/never saw when they were youngsters. I suspect the active
flux is a major cause.

Also the pipes were wider?

Generally from what I see most systems without inhibitor (or not topped
up) seem to survive (not flourish just survive) provided they are either
the sealed type or the conventional type in good order.

Then really horrendous corrosion happens with open systems which faulty
layouts which pump over or suck air in.

Occasionally systems can get into anaerobic corrosion. This is where the
oxygen is supplied by breaking down the water into hydrogen and oxygen.
The hydrogen gas then collects in a favourite radiator.
If I meet this I flush the system twice with water - draining it as far as
possible each time. The put in a double dose of inhibitor.
The causes of anaerobic corrosion seam to be:
1) trying to treat a
noisy boiler with acid and then failing to flush a neutralize it.
2) New systems which were not treated with a "new" system cleanser to
neutralize the flux.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html