Cutting cast iron

[Brown and Boris]

How easy is it?

I have an old cast iron fireplace and need to cut out the old fire basket and fire back to fit it around an existing living flame gas fire (thus saving me all the cost on converting the old fireplace and chucking the perfectly good living flame fire already in place).

Would a grinder do it or will that just crack the frame?

[trickywoo]

Only time I've seen it done was with a gas axe - which worked very well.

[Stu R]

A decent angle grinder shouldn't have too much bother doing it.

[HRG]

Easy peasy, but it's very 'dirty' when you cut it. The swarf is full of carbon so it leaves dark grey smears everywhere if you're not careful.

[thinfourth2]

Easier then steel due to the above mentioned carbon

However sticking it back together is a very different prospect

[Brown and Boris]

Souns messy. I may get the local blacksmith type place to do it.

[EINSIGN]

Brown and Boris said:

Souns messy. I may get the local blacksmith type place to do it.

The local blackmith that fixes your horses shoes and sells "gas axes".

[SirDigbyChicken]

A normal coarse hacksaw blade will cut cast iron very easily unless the original casting has hard or 'chilled' spots in it then you might struggle a bit - just have the hoover (not the good one) around to suck up the dust as there will be alot of it and it gets everywhere so dont wipe your face whist cutting! You may have issues using a gas axe - the casting may crack due to localised expansion meaning you would have to heat the whole lot up whilst doing it and ahhhh it all sounds like alot of mess to me. I think a hacksaw and abit of effort is the best way.

Edited by SirDigbyChicken on Friday 17th April 19:32

[Brown and Boris]

EINSIGN said:

Brown and Boris said:

Souns messy. I may get the local blacksmith type place to do it.

The local blackmith that fixes your horses shoes and sells "gas axes".

That's right. Although of latre he has mainly been mending farm stuff and making fancy gates and railings.

[69 coupe]

trickywoo said:

Only time I've seen it done was with a gas axe - which worked very well.

If by gas axe you me oxygen/acetylene cutting equipment, this is by far the worst method to cut Cast Iron.
Cast Iron will oxidize when you try to cut with gas torch, this increases the temperature (molecular structure) actually stopping the process, it will melt through but will be really ugly.
Due to the increased heat the chances of cracking are Hugh unless plenty of pre/post heat are used.

Another method if in a real pickle is to feed a mild steel rod into the gas/flame the use of mild steel reduces the amount of carbon content in the molten pool thereby helping the oxygen blast with cutting.

You can use Oxy Arc which is basically a arc welding process using hollow welding rods where the oxygen is forced down the centre of the welding rod when an electric arc is struck.
Personally I'd use a power/hacksaw, grinder or a plasma arc cutter.

[maser_spyder]

69 coupe said:

trickywoo said:

Only time I've seen it done was with a gas axe - which worked very well.

If by gas axe you me oxygen/acetylene cutting equipment, this is by far the worst method to cut Cast Iron.
Cast Iron will oxidize when you try to cut with gas torch, this increases the temperature (molecular structure) actually stopping the process, it will melt through but will be really ugly.
Due to the increased heat the chances of cracking are Hugh unless plenty of pre/post heat are used.

Another method if in a real pickle is to feed a mild steel rod into the gas/flame the use of mild steel reduces the amount of carbon content in the molten pool thereby helping the oxygen blast with cutting.

You can use Oxy Arc which is basically a arc welding process using hollow welding rods where the oxygen is forced down the centre of the welding rod when an electric arc is struck.
Personally I'd use a power/hacksaw, grinder or a plasma arc cutter.

^^ Now that's a man who knows his welding!

A riveting post, well done. (sorry!).

[69 coupe]

maser_spyder said:

69 coupe said:

trickywoo said:

Only time I've seen it done was with a gas axe - which worked very well.

If by gas axe you me oxygen/acetylene cutting equipment, this is by far the worst method to cut Cast Iron.
Cast Iron will oxidize when you try to cut with gas torch, this increases the temperature (molecular structure) actually stopping the process, it will melt through but will be really ugly.
Due to the increased heat the chances of cracking are Hugh unless plenty of pre/post heat are used.

Another method if in a real pickle is to feed a mild steel rod into the gas/flame the use of mild steel reduces the amount of carbon content in the molten pool thereby helping the oxygen blast with cutting.

You can use Oxy Arc which is basically a arc welding process using hollow welding rods where the oxygen is forced down the centre of the welding rod when an electric arc is struck.
Personally I'd use a power/hacksaw, grinder or a plasma arc cutter.

^^ Now that's a man who knows his welding!

A riveting post, well done. (sorry!).

Ahh riveting, not great for cast iron, but you can't get better that lock and stitching http://www.locknstitch.com/Metal_Stitching.htm

[mat13]

personally would try one of those bosch 1mm cutting discs in an angle grinder seem to go through most things like butter

[Big Al.]

Cuts nice and easy with a hacksaw once you get through the thin hard skin, don't be frightened of it, it really is relatively soft.

HTH.