wrote:

The only way that the solder will fail on Knob and Tube wiring is if the
circuits were fused with improperly sized fuses. If the circuits are
protected with properly sized fuses K&T will last for decades.
--
Tom Horne

OBVIOUSLY you dont know enough about solder, over LONG times it wiskers
and detoriates. now K&T is likey 50 years old or more, and quality of
metals and solder wasnt great way back then.

I fix office machines for a living, at one time did tv and other
appliance repair. in that time every now and then would find a bad
solder joint, that had workewd forever. frequently in low power
circuits where it wasnt and couldnt be overloaded.

Insurance doesnt like K&T because it cost them too much in fire
losses,,,,,,,

otherwise they wouldnt care!!

you go right ahead thinking K&T is safe, all those insurancer companies
just dont know what they are talking about

Below are a couple of links to consider wrt knob & tube wiring.
Although my experience is limited, the times I have seen crumbling
wire insulation with K&T is where it joined ceiling light fixtures,
and that was because of the heat (over heating) due to the fixtures.

In some such cases it was possible to (properly) solder a replacement
extension onto such a wire and then use a sleeve to cover that, followed
by the installation of a junction box to hold the wire safely in place
and connect to the fixture.

Whenever possible I replace K&T, but when not reasonable to replace,
I would be sure the circuit is on a 15A max breaker. Usually
receptacles, which is where the greatest loads exist, and where a ground
is especially desirable, can be more easily rewired with romex.

http://www.waptac.org/sp.asp?id=7190
http://www.maine.gov/pfr/ins/hearing_2003-13680.htm

These links are especially interesting and deserve a full reading.
My comments are just my own opinions and ideas. --Phil