Malable vs Cast

Eileen Olive

What exactly is the difference between the two? which should be used on steam, which on hot water? Any other choices other than brass?

JohnNY

This comes up from time to time.

I prefer cast iron, and quite honestly, I despise when I see malleable fittings on a steam boiler.

To me, all materials have their application:

Service weight is for underground waste.

No-hub is for above ground drainage.

Copper is for water.

Malleable is for gas.

Cast is for fire suppression....and STEAM

It's nice to be able to walk around a building and know what portion of the system all the pipes serve without having to trace them back to their source.



Some very smart and talented professionals will chime in here and disagree with me, but that's fine too.

When it comes to those two materials, it's simply a matter of preference.
Brass shouldn't enter the conversation.




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Brad White_202

Applications

I see traditionalists using cast iron on steam. I personally think it looks better. The fittings are distinguished by larger bosses (thicker sections around entry points) on fittings and tees compared to the malleable fittings which have thinner bosses.

Malleable iron is more "elastic" than cast iron and thus much tougher. This is why the fitting bosses can be thinner. I forget the metallurgy but know that malleable has less carbon and silicon and is annealed in the process.

You can whack a malleable fitting all day and not break it. A good whack with a sledge will crack a cast fitting so is preferred by those coming back to work on an older system.

For instrumentation, I prefer red brass. It is code in some places because when it corrodes it does not flake off nor attract other metals to clog and block safety instrumentation.

EDIT: As JohnNY said, malleable is code for gas. Do not use cast iron on gas. I agree with JohnNY's list by the way, but brass is in my conversation, a whisper off to the side.

Eileen Olive

Thanks for the imput . . . qnd now the magnets

Thank you for being so explicit. Now for the magnets to go into my strainer supplying my stainless HX mod/con. Where might I find rare earth magnets to fit in there?

Brad White_202

Magnetic Personality

Personally, I get my magnets from Lee Valley (dot com....) but you can find various suppliers on line. What you seek are neodymium magnets. They can be very powerful.

Rather than go for large mass, seek smaller ones with more surface area. Discs or rods, whatever fits best. Your screen should be stainless steel or bronze/brass just the same.

Have fun with your new Chia Pets.

scrook_2

magnets

try www.kjmagnetics.com too for neodymium magnets too.

Unknown

John

Is there a mechanical reason not to use malleable fittings on steam ?

Or are you talking about aesthethics when you say you despise seeing them on a steam boiler ?

My opinion is it makes no difference what material you use on steam - malleable or cast . Both choices will last next to forever .