Sort of a random question (painting)

KC_Jones

I have a feeling I will have a lot of these over the next few weeks and months.  So on my failing boiler the outside of the cast iron is quite corroded (giant chunks of rust).  It got me thinking, do new boilers come with any kind of paint or coating on the outside?  I know paint wouldn't hold up to the flame very well and really wouldn't need to, but what about the top and sides?  Would there be any long term benefit to painting the outside of the boiler with some high heat paint?  Seems crazy I know, but after looking at my old one it really got my brain working.  I don't know if the corrosion is from leaking that i just now found this year or because my basement is notoriously damp.  I generally keep an oiled rag in a sealed metal can that I use for wiping tools down because of the dampness.  Anybody have thoughts on painting a cast iron boiler or am I asking something no one has thought of?  I searched the wall and didn't really see anything on this.  Like I said random question.

Binnacle

won't help

Painting the outside of the boiler will not help that leak.  Can't imagine any benefit and it could cause problems.  Rust on the outside of cast iron is common and a thin non-flaking layer protects the metal.



If the boiler is large enough replacement of a bad segment may be worth consideration.

KC_Jones

I understand

It won't help the leak I was referring to it's new replacement.  Understand most of my dealings with cast iron is on car engines and in that world all corrosion is evil and hated.  I basically work from that perspective.  And as far as non flaking, that is what my current boiler has, but it's above the leak and it's a massive amount that's what made me think about it.  As far as rust protecting cast iron, that's a new one on me?!  I have seen cast iron rust into oblivion so not sure how a layer of rust can stop the chemical reaction of the iron with the oxygen?  I do know there are some newer alloys that are by design intended to rust slightly as an oxygen barrier, but wasn't aware that cast iron was one of them.   I am not disagreeing with you, but I despise rust and on my new boiler I am trying to think of any possible thing to increase it's longevity.

BobC

The best thing you can do

for a steam boiler is to make sure it gets piped correctly. It's not cheap but considering it can last 20 - 30 years you want to make sure it's done right.



The next thing is to find out why the old one failed and do what it takes to make sure that cause is fixed. If you don't correct the cause for failure, the new one will fail the same way but quicker because new boilers use thinner cast iron.



In my opinion painting a boiler block is a waste of time because they fail from the inside out. Put the effort into having it piped correctly and make sure you don't have any water quality issues.



Bob

KC_Jones

Thanks

To you both for the input.  Like I said it was just a random thought I had.  Like I said I have a lot of experience with cars and cast iron engine blocks and such and I paint everything I see so it's probably just a habit to think about it.

ChicagoCooperator

Our boiler was painted

After we had some repairs done to the boiler base, it was painted "as a matter of course" - granted, our boiler is 80 years old, but preventing corrosion on the exterior would seem to me to be cheap insurance, particularly if you have a damp basement.

KC_Jones

linseed oil and graphite

Is an old steam train trick for coating the smokebox area against corrosion.  Not sure what that would smell like in my house!  lol of course they are dealing with much higher temps and are outdoors.  I am kidding of course!