cast iron vs mal. ftgs. in steam installations

RP Millers Heating

Hi there Dan;
It was brought to my attention today that cast iron fittings are the best for steam heating. Could you please let me know what your opinion is? I have been using malable fittings for over 5 years with great success. The only reason is that supply houses carry more mallable than cast. To me mallable are stronger so I didn"t care about the cost. Thanks for your time your are a great person for what you do. Godbless *** Ray

gerry gill

cast is for steam

because when it has to be taken apart, and it wont unscrew because its been baked on forever, you can break the fitting off the male threads with a hammer..

RP Millers Heating

cast iron vs mal ftgs in steam systems

For several years now I have come across stubborn ftgs but an old timer taught me to use a new tool called a sawzall...
Once you score around the ftgs in qaurters you can hit it like a cast iron with a hammer and you will find that it pops right off the pipe, but just make sure you do not cut too deep or you will damage the threads on the piping.

Paul Mitchell

Hmmmm

New tool a sawzall?....Sense a little hostility or sarcasm??? You asked we answer...Dan will answer if he sees the question. I asked and that was the answer I got. We have a problem getting cast fittings also. So I use Black only if I have to. Sawzall trick works sometimes...

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mad Dog

Two reasons to use Cast Fittings................................

They look formidible and classic- even foreboding if you will, unlike wearing a pair of sneakers with a tuxedo which is what malleable fittings look lie on a steam boiler. Do we use them sometimes when we have to? yes, but it feels like cheatin. Second reason: Its what My mentors taught me, and I will not let them down. Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Unknown

I didn't sense hostility

It sounded like he was self depreciating because he shoulda thought of it sooner by himself . Just like me . We repiped steam returns and had to take apart 2 - 2 by 1 black malleable couplings . I made 2 cuts on the outside of each coupling and it came right off . If it was cast , I could have broke em , but would have knocked the asbestos insulation on the mains all over .

We only use malleable and I think my work looks just as good as an all cast install . With Teflon and thread sealant the fitting will come apart like butter , even a few decades from now .

gerry gill

well, i'm stick'in with Mad Dog,

we will continue to use cast iron cause if the old timers wanted us to use steel they would have taught us that way..like MD says, sometimes you run out of a particular cast fitting and have no choice..hey MD i just ordered in a 44'' ridgid chain tong wrench for the big stuff, i'll let you know how it works..cant wait to see if its easier than a 48'' pipe wrench.

tim w

cast iron best

especially on larger sizes (2" and up) was explained to me that the mallable 90 or tee after heating/cooling dozens of times will 'stretch' and not return to original shape/size which may lead to leaks in future, also saves some mallable stock for the guys running the gas lines.):

Tony Conner

\"Malleable Iron\" Is Just...

...cast iron that has been heat-treated in an oven to relieve it's brittleness. The process somewhat improves the tensile strength and enables the material to stretch to a limited extent without breaking. This is from the "Piping Handbook" by Nayyar.


Some guys like one material over the other for various reasons, like appearance, or that you can break a cast iron fitting to get it off, and that's fine. Other than the heat treating, which gives malleable fittings a higher pressure/temperature rating by reducing the brittleness, the materials are identical.

For what it's worth, you can often get a stubborn malleable fitting to break-free by by pounding it. It won't break, but it'll often let you unscrew it. Another method that works for all kinds of fittings it hit the pipe wrench with a hammer. DON'T HIT THE HANDLE OF THE WRENCH - hit the back of the wrench down between the adjusting nut and the heel jaw, while somebody else is giving a good, hard sustained pull. Note: not recommended for aluminum handled wrenches - I've got an old iron-handled 3 footer and a 2-1/2# blacksmiths hammer I use for this. 99% of the time, pounding the fitting and/or wrench will work.

Mad Dog

I rarely break the cast fittings apart

for the same reason...asbestos and posiible damage to pipe and fittings on the rest of the system. Turbotorch and wrenches always do the trick. No doubt your jobs are neat Ron, and I know you don't do the ordering anyway. Malleable is fine, I just prefer the look of cast. Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mad Dog

Thanks Tony good explanation,but why

do they "look" different? Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mad Dog

Cool...I love the big wrenches

I got to work on 12 " screw pipe once. We used a huge "compound" wrench. It had a hinge on it for leverage and was chained to the pipe like a pipe vise. Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Tony Conner

None...

...of my books seem to say why they look different. 125 cast iron fittings have wider bands that interjoin on fittings like tees. 150 malleable have narrower bands that don't interjoin. The only reasons I can think of are the heat treating means enough of a rating increase to permit thinner bands, and/or maybe so you can tell one from the other at a glance?

Kal Row

hey i cant even lift

some of the wrenches i've seen mad-dog with
so i use flanges so i don’t have to worry about taking it apart later – besides if we build it like mad-dog does – then all these problems don’t happen – cause if it’s done right, 4 inches of dry steam, will fill a house at 40 miles and hour and 2 inches will maintain it, and if the system isn’t doing that, then fix it!

RP Millers Heating

cast vs mal ftgs

`Sorry if I seemed sarcastic, I did not mean to offend or anything I am only learning daily, I would like to know if there is a heating loss or strength problem with these different types of metals. Also I have found that heating does in fact work easier but the fumes disturb workers and customers. The asbestoes usually has been removed or covered for future contaminations. As far as what the old timers us to do, I am curious to what they would say now. The materials today are not the same as the past, but Dan what do you have to say?

Rudy

Cast is King

I just cant bring myself to pipe steam or HW with malleable. I might cheat here or there in a wall or floor but NEVER in the boiler room. Like MD...I think it just looks right. When I've added to old Dead Men systems I eschew copper with a vengeance. When I added basement zones to a beautifully engineered (1910) converted gravity HW with screwed pipe and Burnham Baseray I told the owner he could save a couple thou with copper annd fin but he'd have to get someone else to do it. I got the job and and used 1 and 3/4" cast fits.

Rudy

Cast is King

I just cant bring myself to pipe steam or HW with malleable. I might cheat here or there in a wall or floor but NEVER in the boiler room. Like MD...I think it just looks right. When I've added to old Dead Men systems I eschew copper with a vengeance. When I added basement zones to a beautifully engineered (1910) converted gravity HW with screwed pipe and Burnham Baseray I told the owner he could save a couple thou with copper annd fin but he'd have to get someone else to do it. I got the job and and used 1 and 3/4" cast fits.

gerry gill

Mad Dog-does that compound wrench

really make it easier?

Mad Dog

I'll buy that

Thanks Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mad Dog

Like Arm wrestling.......................TECHNIQUE IS EVERYTHING

mAD dOG

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mad Dog

nice!!!!!!!!!!!

i JUST LOVE HOW "CHUNKY" AND "MEATY" THEY LOOK. mAD dOG

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mad Dog

fORGET ABOUT IT!!!!!!!!!!!!!!!!!!!!!!!

To get enough leverage to make up 12" screw pipe, you'd need a ten or 12 foot pipe wrench with lever bars. The compound wrench has the jaws of a regular pipe wrench, whcih attaches to a hinge, which is chained to the pipe. Then a handle the size of a 4" pipe wrench slips over, a big chunky post, and you turn away. It took 3 good men to hold the fittings and get the first few threads caught. We also had to pre fab the pipe at an industrial shop, so everythinhg had to be ON THE MONEY!!!!!!!I will always cherish working under one of the two greatest mechanics I have ever seen, Mr. John J. Nolan. He was a real harda--, but it just made you try harder for him. Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mad Dog

I'm sure you could find one in a rigid catalog

Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

gerry gill

Hey Mad Dog,

i sent you something in the mail this morning that i thought you would find interesting since you've built a one pipe steam system..you should recieve it in a couple days..

Nick W

Reposting from old thread.

This was my response on September 27, 2003 in a similar thread and I stand by it:

It doesn't matter that malleable fittings are stronger. The tolerances of both materials FAR exceed their usage here. Cast iron fittings are for use with steam. Black malleable fittings are for gas pipe. If for no other reason, gas and steam pipes should be easily identifiable throughout a structure. When I see a steam boiler piped in bm fittings I'm inclined to think that a shortcut was taken. It's easier and takes up less space to stock one type of fitting rather than two.

Finally, is there nothing to be said for just plain tradition? What really is at stake here?

It's consistent with the antiquity of the system.

Here, on the Wall, we talk about the Dead Men, old piping practices and designs, ancient books about steam heating and distinguish ourselves from the hobbyists all with such reverence.

It seems so simple to me, guys; Use steam fittings on your next steam boiler.


To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

gerry gill

I concur

absolutely

Unknown

Not so simple

as just going down to the local supplier , and the supplier having everything you need in cast . I know from years of steam boiler installs on Long Island that it's very rare to find all you need in cast in one place if your piping is over 2 inch . I know you work in the city , I used to work there ( about 8 years ago ) , and cast fittings were more readily available . We do take a shortcut by using copper for the returns , but there is never a shortcut taken with my header piping . No matter what .

One thing I have to say is cast iron and malleable mixed together on a boiler header looks very shabby .

A question . Do you really think someone would be confused between steam mains and gas piping , if both had malleable steel fittings ?

Dave Tourigny

Cast or Mal

I like the look of CI on steam and Mal on water. Mal is code here for petroleum and air, because it won't crack.

My experience has been CI probably will make a more reliable joint due to it's ability to hold its shape versus mal which can become deformed by overtightening or poor wrench bite.

I was interested to hear the sugestion that you can free up a fitting by hammering while working a wrench on it, I will give that a try next chance we get.

Dave

Maine Ken

Without doubt cast w/ steam and bi w/ water. I have broken way too many cast fittings to use them on both.

Tony Conner

The Old...

...Audels books from the '20s show where to hammer a wrench while pulling on it to make stubborn nuts or fittings bust lose. We pound the reluctant fitting a few times on the band first, and if that doesn't work, then the bulge in pipe wrench handles just above the adjusting nut seems to have "hammer here" written all over it. A steady pull, as hard as you can manage for 10 - 15 seconds, combined with a few good shots from your partner's heavy hammer on the bulge in the wrench handle will usually do the job.

rich pickering

I was taught that cast iron doesn't corrode the same as mallable.Compare a 80 year old wet return to a 2 year old fitting in a radiant system that doesn't have an oxygen barrier.We've still got some threaded cast drainage fittings in the back shop.

Mad Dog

cool thanks gerry

Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Tony Conner

Wrought Iron...

... was the key material, in many instances. Not cast iron, malleable iron, or steel, but wrought iron. It was just about bullet-proof as a piping material ... but it cost 25 or 30% more than steel or cast iron. As far back as 1916, there were mills getting out of wrought iron production, because not enough people would pay for it. The corrosion resistance of cast iron vs malleable iron is non-existant, because it's the same material, malleable has just been heat treated.

Another big factor is that there is a lot of poorly mixed scrap in the melts at the mills, along with other corners being cut over the last few years. Even 316 stainless steel pipe has suffered, but I didn't know why until recently. Many manufacturers of stainless steel products apparently specify slighty higher than normal sulphur levels in the stainless they buy for fabricated assemblies (like seamed pipe) if they use TIG for the welding. Elevated sulphur levels makes the metal puddle better, and the welding goes faster. And that's just great, except that the extra sulphur can drop the corrosion resistance of 316 can to that of 304. I think that similar games are played with copper, steel, and other pipe & fitting materials.

bob_25

What about

300lb mallable they look like cast and most industrial pipe suppliers stock them. Some call them railroad fittings, but only the ones that say AAR are really railroad. Anybody know what Ridgid pipe wrench handels are made of? How many have you seen break? bob

Jim_22

Two cents

I believe Tony has it! I've always understood, "back in the day" that cast iron was cheaper, so you used it on jobs that you could, as in steam, drainage, fire protection.

Cast does have the "look" in a steam system, I love the 3" & 4" drop header photos that get posted.

As for the Ridgid pipe wrenches, I'm gonna guess they are heat treated mallable cause I've never been able to break one, but not for lack of trying.

Jim