Subscribe or Renew Membership Subscribe Renew

Painting hot water radiators

hammer's picture

Just started a rehab on a 1920's house with hot water heat. some of the radiators have covers but the ones without are in need of fresh paint. Some are slightly rusty and caked with dust and whatever.

What is the best preb and finish for these?  Do you close off the heat as they dry?

I have an airless sprayer.

(post #100286, reply #1 of 9)

I don't have the best answer for you but I'll tell you what I've done at my house
first batch of 6 or 8 all prepped w/ sandpaper, wire brush, tooth brush etc ( all in place ) primed, sealed w/ rustoleum type spray paint then covered w/ some linen white esque off the shelf spray
most recent group all pulled to do dougfir floor and bathroom floor using same cleaning and priming w/ shellac base primer brushed on then brushed on coats of semi gloss latex I was using for the woodwork
the spray on group work great and the brush on contingent's heating quotient seems ( by touch of hand ) to have been downgraded but then I think where else is the heat going?
mine are ballbreakin beasts that as far as I'm concerned moving very far from there final resting place is not much of an option
there arte those that will take them to powdercoat them
I came home w/ a deep brass metal heat favorable spray paint in a can and my wife did not respond very favorably - so on w/ the whitish coatings
hope this helps

(post #100286, reply #2 of 9)

I just did a job where I took the radiators to a local farm machinery dealer who had a soda blaster. They were painted by the home owner's son who has a body shop, so I don't know what kind of paint he used.

The soda blasting was pretty expensive, but did an excellent prep job. There are many different media they blast with. You might check with someone who restores old cars or machinery.

These radiators were small enough to haul out of the house.

(post #100286, reply #3 of 9)

As with any painting project, surface preparation is key.  For the finish, there are numerous high-temp paints available.  If you can't find one at your paint store or home center, you may want to try an auto parts store.  Hot water heat does not get as hot as steam heat.  I was working on one project where the wrong type of paint was used on a steam radiator.  Every time the thing heated up, the homeowner was overcome by smelly fumes.  The painters paid to have it taken away and sandblasted.



The Breaktimer formerly known as "Steve-O"

"Preach the Gospel at all times; if necessary, use words."  - St. Francis of Assisi




"Preach the Gospel at all times; if necessary, use words."  - St. Francis of Assisi

No, I didn't vote for him; but he IS my president.  I pray for the his safety, and the safety of his family every day.  And I pray that he makes wise decisions.

(post #100286, reply #6 of 9)

Thanks for the caution. I could see that some paints could cause fumes if heated too high. I have an addition that is being demo'ed and I can practice on the radiator that will be removed from there.

Do you know the temperature difference between hot water heat and steam?Asumming steam at about 212 deg. I beleve this is not water.

(post #100286, reply #4 of 9)

If you can remove them & have them blasted ---soda --- glass works great too.

Then the cadilac finish is powder coating-----woo hoo any color you can dream of.


(post #100286, reply #5 of 9)

In one particular low-end rental unit, I painted a steam pipe that was so hot, I couldn't touch it and the paint dried in seconds with visible steam rising off.  One advantage to painting it while it's hot is that the paint will dry before there's any chance of rust forming.  In general, steel should not be painted with latex.

I don't recommend painting anything this hot, but the paint adhered with absolutely no problem.  In fact, I've been back there since and there doesn't seem to be any long-term issues either.


(post #100286, reply #7 of 9)

Here's an interesting article on painting radiators:

(post #100286, reply #8 of 9)

I have had good luck doing the following for STEAM radiators:

1.  strip with methylene chloride-based stripper, and sometimes with the stripped fortified with other ingredients for especially tough cases.  The fortified strippers are sometimes called Airplane Strippers.  Cover the radiator liberally, wait longer than seems possible, attack with brasss brushes to get all the gunk off.   2. re-paint with high temp paint (brass or bronze color).


I have had wall paint crack and peel right off the radiator in chunks, and it has been well-cured paint, not just applied yesterday.


Bob Chapman

(post #100286, reply #9 of 9)

Painting radiators in a hot water system is no problem at all.

I have used Rustoleum, but my favorites are non-lead based paint from an outfit in Ca that provides paint to the hot rod industry -- House of Kolor. From them I have been able to get paints that mimic the colors used originally in turn of the century houses.

The real problem, as others have pointed out, is the the surface preparation. If at all possible, it is best to remove the radiators and have them sand blasted.

If they are too big and heavy to move, then you are faced with doing them in place. If they have never been painted, it is not so bad. But if you have units that are glopped up with paint, especially if it is peeling and chipping, you have got to get it off. That means either scraping (my preferred method) or using a stripper.

"It is what we learn after we think we know it all, that counts."

John Wooden 1910-

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-2010