I have several steam radiators that have multiple layers of paint. Two of these radiators have bubbles that appear in the paint when the radiator is hot, and these bubbles have turned into splits and peels in the paint surface. I was planning to sandblast the radiators down to the bare metal and repaint them. Anyone have any specific recommendations for a paint product that suits this application?
Thanks
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Replies
I've used Rustoleum on my steam radiators, and it works fine.
Al Mollitor, Sharon MA
Steam radiators must be painted with a high heat paint, or the paint will bubble and fail. Unlike hot water, steam radiators will reach temperatures in excess of 200 degrees F.
That's not correct. Steam radiators may get too hot to the touch, but never get to 200 degrees, or have a direct flame on them that high heat paint is for. So, regular rustoleum is fine, has lasted for years on several of my radiators that have been stripped (not by spending $500 at a shop for sandblasting either), and comes in more colors than black, white, grey, and tan.
Many people waste money on powder coatings at the auto body shop after having them sandblasted. The heavy powder coatings would obscure the linework cast into the fins of older radiators, defeating the point of stripping them in the first place.
...that's not a mistake, it's rustic
Edited 4/15/2003 12:46:57 AM ET by Bungalow Jeff
My infared thermometer will tell you different. Use a high temp primer and paint. A body shop made that mistake and I had to remove one from a house and have it redone. Thankful it wasn't a whole house full of them.
BTY, most radiators are painted white or silver. Do you know the best color for the most heat?
Yesterday I couldn't even spell plumber, today I are one.
Flat black would probably radiate more heat than white or silver, but decorating concerns usually prevail.
Al Mollitor, Sharon MA
does it realy cost that much for sandblasting a radiator in your area?
$500 is obnoxious. in MN i've never seen it cost more than $75 for blast and prime. $50 just for blast.
rg
Yeh, really. I usually get them blasted, primed and painted for $100.
When converting steam radiators to water (assuming they can be used both ways) I don't try to loosen the plugs and bushings. Usually the plugs are hollow core. So, instead I cut them off flush with a reciprocating saw and then cut some shallow notches from the inside. Don't go into the radiator threads. Knock the pieces out, clean the threads with an old copper fitting brush in a drill and screw in the new bushing. I like to use teflon tape AND pipe dope. Careful not to over tighten or you'll crack the radiator. For the small vent hole, I just center punch it and keep drilling with larger bits until I get close to the thread. Then knock it out and run a tap in it. When plugging the old vent hole be really careful not to over tighten it, the tubes crack really easy. Always a good idea to flush out all the mice and rust, plus pressure test (30# max) before sending them off to the paint shop.
Yesterday I couldn't even spell plumber, today I are one.
The $500 is a price from a homeowner, so it includes the cost of taking the radiator back and forth, however, I am in the NYC metro area, so the prices will be much higher for all options.
Thick coatings like a high heat paint or powder coating will reduce heat ouput in a steam radiator. Color plays no part in the thermal transfer for a radiator. ...that's not a mistake, it's rustic
Color plays no part in the thermal transfer for a radiator.
WRONG! It plays a significant part. I will find the specs for you all.
I used to run a small powder paint shop in Detroit area for auto parts. On several occasions we painted old cast iron steam radiators for people off the street. Usually semigloss black polyester. Everyone was thrilled with the results.
Any method you use, spray paint the radiators to get back into the tight areas. If you are able to find someone in your area to do this, a phosphate conversion coating is not necessary because of the heat, but should not matter either way. I would recommend powder if you can find someone, I have done both wet and powder. Your problem with powder will be the choice of colors, even though they are made in just about every color available usually there is a minimum quantity buy (for a reasonable cost) say 100 pounds, second the coater will up charge you for a paint changover. I used to charge around $20 - $100 based on size, quantity and color (still used basic colors, black off white).
Other stripping methods would be to burn off the paint in a burn off oven or salt brine. Look around in yellow pages for a paint stripper, industrial. Will take less time than sand blasting with better results. Arrange the painting first and move the stripped radiators from the stripper to the painter without delay to prevent red rust.
Good luck.
Black will radiate more heat than lighter colors. This is a fact - simple physics, not debatable. This is the main reason the radiator in your car is painted black.
Not that I would ever paint a visible radiator in an inhabited space black.
Use heat paint on steam radiators. If the system is working properly (many one pipe system are not) the radiators will get very close to the temperature of boiling water, possibly a little hotter depending on the chemical make-up of the "water" in the boiler.
Even on hot water radiators that do not exceed the typical 200 degree F limit of most paints, heat paint has advantages.
Id suggest just taking the radiator to a powder coating shop. They can strip and sandblast your radiator and powder coat that sucker and youll only need to do it once.
Powder coating isnt deathly expensive, but it sure as #### is more durable a finish then rattle can paint.
I like the idea of the powder coat. Only problem: How to get these behemoth 10-section cast iron suckers down a tight staircase without getting crushed by them? I've moved them before, when redoing the floors, but only across the room, never up or down stairs. It's all two people can do to hold them off the floor and scoot like hell before your arms drop off. (or before divoting the floor). I'm guessing they weigh near 300 lbs a piece.
I have an enclosed back porch and I was going to take the radiators out there and sandblast them myself - have a compressor and should be able to talk my friend into letting me borrow his portable sand blaster. Then I was going to spray them with a paint gun.
try to separate the sections and carry them out one at a time, your powder coater will thank you.
James
If you try to separate your radiator into sections you will need to prepare yourself for putting them back together (they were not designed to be taken apart).
Go to heatinghelp.com and discuss it with them and make sure they can get you the proper nipples you'll need before you start.
Or you could end up ruining all your radiators.
Not that you will, just that you could. Better to be sure before taking the risk.
Moving radiators is not typically done lightly (pun) and I worry that some of the advice given here might not be from folks who have actually ever done it. Powder coating is nice, but getting your heavy radiators in and out of your house is a significant part of considering it. There is fine paint available (and good strippers) that you can apply on-the-spot that are probably a better way to go for most of us than going to all the trouble of getting them powder coated.
Norm
Norm, I've been lurking in here - any recommendations for good rad stripping products? thanks.If you can't play a sport, be one.
Peel Away makes good stripping products that have served me well. I get it at my local Sherwin Williams store, but I think any big paint store would carry their stuff (they make several formulations, depending on what you want to strip).
Peel Away is organic and takes a few days to work, but cleanup is a breeze (remove & clean up with a "green scrubby" pot scrubber, or a plastic scraper and warm water). There is a bit of smell, but no real fumes to deal with, and its all safe for the environment (but use gloves because its hard on the skin).
Norm
Thanks Norm. I'll take a look for that product. It's definitely an advantage if I can go into the stores with a few sensible sounding words - the staff seems to be more helpful if you've got a clue! If you can't play a sport, be one.
Bad advice pal.
You must really hate this guy! LOL
Ok everyone I remember from physics class, several, that a black body will best absorb heat, but I do not remember that applied to the radiating of heat. Most hot things seem to turn red. If so than why don't they coat all aluminum heat exchangers on computers black or how about the cooling fins on large outdoor liquid O2 or N2 storage tanks black?
As for powder coat. The polyester powders are baked to cure the paint at temperatures higher than boiling water and if you are really that concerned they do have high temperature powder paints and yes they have them in colors other than black. The problem will be getting a powder coater to change over let alone the minimum buy, mine used to be 50# of powder. Now, since powder paints are generally applied thicker than wet paints, partly because of the shrinkage, I do not know if they would tend to insulate the radiator.
Find the powder coater first, some have the ability to do the stripping for you, if not ask them who they use. I guarantee they have parts stripped regularly. I powder coated radiators from several customers and would not recommend the sandblasting method. My preference would be chemical, hot salt, or oven burnoff followed by washing.