Cutting cast iron

I posted some time ago about fitting a cast iron fireplace into an existing marble surround. The correct way of doing it would be to remove the surround - but this is a great deal of work and I'm worried about breaking it. The other way would be to trim the edges off the insert so it can be fitted with the surround in place. (it will be purely decorative) It's about 1/2" thick. Obviously, I suppose, an angle grinder would cut it but they tend to terrify me ;-)

Any safer way of doing it? Could I take it somewhere to have it done - perhaps with a plasma or whatever cutter?

Reply to
Dave Plowman (News)
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Reciprocating saw, or even a jigsam with a metal cutting blade. Time is on your side :-)

Reply to
Phil

Oops, that 'w' is in upside-down ^

Reply to
Phil

I think I would go with an angle grinder personally. One problem with this sort of cast iron is that it is quite likely to contain nasty hard slag inclusions. These are more likely to make a reciprocating saw "kick" than a grinder. If you have a good flat surface to run a jigsaw on that might be OK (variable speed jigsaws are fairly easy to control).

With a grinder, start with narrow, flat cutting disks and cut as close to size as you can. If you need to "trim" afterwards, use the thick dished grinding disks. It's not going to be a quick job.

I suspect that someone who knows what they are doing might be able to do it with a gas axe or plasma cutter, but I would be worried about cracking it through differential thermal expansion. And you would probably still need to clean up with a grinder.

Reply to
newshound

The other specialist method which I forgot to mention is electro discharge machining (EDM) which would definitely work. ISTR reading about people who have DIYed this in the States, although I wouldn't recommend this for just one job!. You might find a workshop who would take on the job.

Reply to
newshound

+1.

This time an angle grinder IS the correct tool.

Reply to
The Natural Philosopher

It's ALWAYS the correct tool...

Reply to
Frank Erskine

Yeh - but I'm terrified of them. ;-)

Reply to
Dave Plowman (News)

In message , "Dave Plowman (News)" writes

Invite Frank along to do it?

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Reply to
Tim Lamb

If you have the time & fancy getting fit you could even do it with a hacksaw. Blade rotated through 90 deg for long cuts, get a blade with the right TPI for the thickness to be cut (approx 4 teeth in the cut for most cast iron).

Phil.

Reply to
Phil

A 9" angle grinder with a diamond blade will do this job in under 5 mins.

I would paint a thick white line down the edge to be cut. When dry use a thick marker pen to mark the line of cut. It will be hard to see if you mark direct on to the cast. Or, if it will stick use masking tape to receive the marked line.

mark

Reply to
mark

Might give the jigsaw way a try. Are there special blades for cast iron? Any lubricant help?

Reply to
Dave Plowman (News)

Just coarser than normal metal cutting blade for a thick cut, no lube for cast iron.

Reply to
Phil

Metal cutting blade. B-) Note the comment above about the TPI, that's a minimum and is a good rule of thumb for cutting many materials. Don't really know about a lubricant, a spot or two of light oil won't harm though.

Reply to
Dave Liquorice

I've got a variety of jigsaw blades, but don't remember any being marked as for cast iron. Although those 'diagrams' showing what they can be used for might as well be in Russian. ;-)

Reply to
Dave Plowman (News)

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for thick stainless/inox ought to do pitch/set/rake - wise.

Reply to
Phil

Only sensible way. CI doesn't like plasma, it's too heavy to easily pass it through a bandsaw and reciprocating saws leap around all over the place. Biggest diameter possible for the disk cutter gives the straightest cut.

Reply to
Andy Dingley

snipped-for-privacy@davenoise.co.uk...

or white "tippex" in a pen type dispenser will draw a nice white line

2 or 3mm wide straight onto the CI

Jim K

Reply to
Jim K

Hi Dave, Jane here, I was just googling this as I have exactly the same issue - I know it was three years you posted this but what did yu do and how did you get it to fit? Any advice would be a great help. Thank you!

Reply to
slinksbyjanerafter

Can't really help as I gave up the idea. Sold the insert for a decent price and went for plan B. ;-)

Reply to
Dave Plowman (News)

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