we have an old cast iron bath that takes 2 daysto drain away the u-bend has a very tight turn on it and I fear that it is "furred up" on the inside no amount of drain clearing fluids make any difference, thethin flexy drain clearingstrip cant get past the turn of the u-pipe. To make matters worse the cast iron u-pipe is then fitted onto a lead pipe that drains it away to the tank the lead pipe is running easy enough as the sink is connected into this and has no problem draining away. what is the best way to deal with this as I am not sure about how to seal lead back onto cast iron. we live in the highlands and have very peaty (acid) water

John hughes, December 2008

Kleeneze vacuum suction pump, kind of an oversized bike pump with an open ended big rubber seal around the bottom, which you place over the bath/sink/showertray plug hole. Tilt it back a wee bit and draw in water, re-cover plughole and hold firmly. Pump up and down several times till blockage is cleared.
Safe and chemical free. Just cover over the overflow first to avoid splash back.

Scotty, January 2009

Might try adding Caustic Soda to the water when it's down to about one inch or so and mixing it up with a stick - the solution burns the skin and strips paint so take great care with splashes.

Caustic Soda comes dry in 2.5Kg plastic jugs from most good old fashioned hardware stores - unlikely to get it from the likes of B&Q - excellent for cleaning cooker shelves too.

Peccavi, December 2008