Do l need a special blade to cut cast iron?

Yes

It's a $5 blade, but I use it on several cast iron cuts before it goes out.

The Lennox cast iron sawzaw blade last a little longer than the others.

I don't know where to tell you to get one except any plumbing wholesale or supply house.

BTW the $5 cost is wholesale, so you may pay a little more.

EDIT

The bandsaw the others are talking about will work, but the blade cost a lot more to replace, and is only good for a few cuts on cast iron.

The sawzaw does not take long at all. I cut cast iron for a living, and know.

The best way to cut that would be with a fiber blade on a cut off saw, or get one for a circular saw, but the circular saw probably dosen't have the depth to cut thru a 4"o.d. pipe. A chin breaker may not be able to fit behind the pipe, depending on how much room you have. You can use a sawsall, but it will take a while, use a hack saw and hopefull you'll be done by spring. If u end up using a saws all, i suggest buying a fiber blade for your cicular saw, cutting as much as u can with that, then use the hardened sawsall blade, with a high tpi(teeth per inch) to finish your cut.Good Luck John.

No. Any metal cutting blade for your sawsall will do just fine. Cast iron cuts very easy.

get a metal cutting blade for your sawzall, probably a 14 tooth per inch, and use kerosene or light oil (3 in one will work) to lubricate the blade and the cut. the kerosene or oil will speed the cutting, and kerosene is a recommended lubricant for working cast iron. If you have an adjustable speed sawzall, set the speed control on about 3. More speed is not better in this instance; it will burn up your blade faster.

Cast Iron can be cut with a hacksaw. No fun!!!!!!!!

But There are special blades made for reciprocating saws. hardened teeth, abrasive grit, carbide and diamond.

If just a few cuts try the hack saw. for multiple cuts use the recip saw.

for a lot of cuts rent the chain cutter.

the slickest way is with a mini-grinder with a diamond wheel.

certain, there's a particular blade made only for slicing forged iron for recip saws. It wouldn't have tooth. It has a coating of abrasives on the the teeth area. they are frequently black and they artwork tremendous. you'll go via too many of the bi-metal blades.

A granular carbide coated blade will do the trick.We have cut hundreds of pipes with this blade.

a bandsaw will cut through it...faster than anything else mentioned...a sawzall will take forever even with the diamond edge blade

Milwaukee portable band saw

cause blade hacksaw