Thread: Best way to cut a cast-iron bath in half?

Dear Forumites,

I'm posting this thread in a couple of other Forums besides this one, because it really spans across the assorted scopes of "Power Tools", "Metalworking", and "Kitchens, Bathrooms, Theatres, etc", since folks in any of these Forums could have encountered a similar problem, or tried to cut a similar material.

Anyhow, as the title suggests, I am wanting to cut in half the cast-iron mini bath that is in the bottom of the shower recess, so that it is of a size and weight that makes it more easily removable. The bath is enamel lined on the upper surface, and I estimate that the walls and base must be at least 5mm thick - possibly even thicker - as I think it would be difficult to cast something that big in that shape with walls that were any thinner.

Not wanting to wrestle with the 9" Angle Grinder over the thing lest I killed myself, I first tried putting a 180mm metal-cutting disc into my 185mm Circular Saw, but after an initial penetration of only 5mm or so, it didn't really seem to want to trouble the cast-iron any further at all... My brother reckons that the enamel lining might have been "glazing" up the disc (and he could well be right), but I haven't been able to have a close look at the disc yet, because I haven't been back to the flat yet. Whatever the case may be, the bath is a truly tough proposition to tackle. I don't know how they even got the thing into position in the first place...

The way I see it, these are my options at this stage:
1) Get out the 9" Angle Grinder and see if the extra grunt therein compared to the 185mm Circ' holds sway. I may have to grind out the enamel in a thin straight line first with a masonry disc if the enamel on the bath is indeed "glazing" up the metal-cutting discs, but the cast-iron under the enamel might well end up "glazing" up the masonry disc as well...
2) Think about either buying a metal-cutting blade (as in "cold-cut") and seeing how it goes on the mighty $37 185mm GMC Circular Saw. Irwin do a blade in the correct size for about $119. Not sure how it would go in cast-iron though.
3) Have a think about buying the Ozito MCG-960K 1200w 185mm Metal-Cutting Saw that already has the correct type of cold-cut blade and is set up for catching the metal swarf, but I'm not sure whether you can even still buy it. Did not want to stretch to the $550 odd or so that the Makita would set me back...
4) Don't think a Jigsaw is a realistic option but would welcome the opinion of others regarding such...
5) Bring in someone with an oxy-torch, but I'm worried about what the heat would do to the concrete floor about 150mm below the bath. Maybe it's not an issue...
6) Belt the bath with a sledge-hammer until it cracks in two, a'la what my Plumber states as being the correct way to remove them. I think I could well possibly kill myself attempting this method...

So, any thoughts anyone regarding the best way (or only way...) to accomplish this seemingly crazy task?

Many Thanks,
Batpig.

Replies here