Best Spray Paint for Old Radiators.....again

AdmiralYoda

I have four radiators that are 100-125 years old and caked with many layers of paint. I'm not looking to restore them to 100% original quality but want to do the best I can with what I've got.

I plan to pressure wash the radiators to get rid of any loose paint and hopefully get it close to bare metal and if any built up paint still exists I'll use a chemical paint stripper on those spots.

I am probably going to end up with some bare metal, some surface rusted spots and some paint that is still adhering. I'd like to use spray paint as I will certainly have drips and runs with a brush.

1. Should I use a regular primer, an etching primer or "Rusty Metal" primer on the radiator after they have dried? Then follow up with a good enamel spray paint?
2. Another thought was to go with my automotive roots. After pressure washing I would use POR-15's Metal Prep which is a zinc-phosphate wash that lightly etches the bare metal and neutralizes any remaining surface rust. Then use their self-etching primer and their Direct-to-Metal topcoat.

Open to ideas! Any option that will be durable and last a long time and can be sprayed out of can would be greatly appreciated!

AdmiralYoda

To follow up on my own question. I contacted POR-15. They recommend priming with their Rust Preventative Coating (brush on), followed by their aerosol topcoat. They said that will be the most durable, longest lasting solution.

flat_twin

Rustoleum enamel spray paint is what we used on our hot water rads. Still looks good several years later. No stripping was needed as they only had the original paint (or what was left of it).

Jamie Hall

This keeps coming up. I have used, for more than 15 years now, high end acrylics. I use Benjamin Moore's Aura, but the other top end paint makers have equivalents. I've never had a problem with failure of the finish on either steam or hot water, nor is priming necessary. Get the radiator good and clean, as much rust gone as you can and no loose paint, and off you go. Any colour you want.

I did just realise one thing I do do -- these paints don't dry in the conventional sense. They cure in the presence of moisture and air, and they must be allowed to dry at more or less room temperature for a week or so before they are subjected to heat. Once cured they can handle steam with no trouble.

AdmiralYoda

@Jamie Hall I've read many of your posts regarding the BM paints and to be honest...I am horrible at painting with a brush (drips, runs and brush strokes) and don't have the equipment to spray it. That is why I'm primarily focusing on aerosol paints.

I've read multiple posts that the typical Rust-Oleum enamels tend to get soft and tacky when heated up. The high heat paints don't but they usually come in flat only and I'm looking for a gloss finish for easy cleaning.

VHT engine enamel seems to be a good choice but I've read that they take a while to off gas, but maybe not.

***edit
I'm also open to giving the BM a try. Worst case I just start over. Looking at the Aura and Advance TDS's...they recommend priming metal with Ultra-Spec HP (acrylic) or Super Spec HP (alkyd).

I imagine there will be some bare metal and potentially light surface rust after I strip the old paint off.

RTW

Back in the early 2000's I had al my cast iron steam radiators: 1) brought to someone that I believe used soda blasting, or plastic pellets, blasted to completely remove paint, not sand blasted , 2) I was told to use a ferrous metal paint, color silver, and then brushed on by a low cost handy man - Lastly, i used a thin, thin coat of pipe dope on the connections to re-install and prevent leaks. However, I did use a rust-oleum spray on two other rads. All rads were never primed and I only used a single coat of ferrous metal paint ( including rust-oleom - that has worked fine to this day. Its possible - but was unknown to me at the time - that a primer coat will benefit in overall appearance and preferred these days.

Jamie Hall

I definitely understand the runs and drips bit, @AdmiralYoda ! I could show you a few... I've gradually learned to take it slow -- and thin coats. You'll get better results with their primers, not arguing with that. I'm just too lazy. There is one radiator I did 20 years ago which was heavily rusted, and the rust is beginning to reappear a little now. Primer might have cured that...

ChrisJ

Jamie Hall said:

This keeps coming up. I have used, for more than 15 years now, high end acrylics. I use Benjamin Moore's Aura, but the other top end paint makers have equivalents. I've never had a problem with failure of the finish on either steam or hot water, nor is priming necessary. Get the radiator good and clean, as much rust gone as you can and no loose paint, and off you go. Any colour you want.

I did just realise one thing I do do -- these paints don't dry in the conventional sense. They cure in the presence of moisture and air, and they must be allowed to dry at more or less room temperature for a week or so before they are subjected to heat. Once cured they can handle steam with no trouble.

How does the paint look after 15 years?

Mad Dog_2

I used Rustoleum High Heat Spray Paint on all of them in the Old Farmhouse in about 2002...21 years...not peeling.. all Good.  Had them all sandblasted professionally first.   Mad Dog 🐕 ed 

ChrisJ

Mad Dog_2 said:

I used Rustoleum High Heat Spray Paint on all if them in the Old Farmhouse in about 2002...21 years...not peeling.. all Good.  Had them all sandblasted professionally first.   Mad Dog 🐕 ed 

Any specific primer?

Jamie Hall

How do they look, @ChrisJ ? Except for one which was heavily rusted to begin with, they all look fine. No rust, no peeling, no problems.

AdmiralYoda

@Mad Dog_2 That radiator looks pretty good! I'm surprised at the sheen of it, it almost looks like a Satin finish. I could definitely live with that. Looking again at the Rust-Oleum High Heat aerosol line, their High Heat Ultra has a semi gloss finish. Only bummer is that it only comes in Black, Aged Copper and Silver.

I could probably live with the silver but was hoping for semi-gloss white.

The final decision will probably come down to this paint or a BM Aura/Advance.

Rust-Oleum does have a Matte High Temp Clear...

Mad Dog_2

No primer...two coats...Done!  Mad Dog  🐕 

Mad Dog_2

I purposely didn't want silver or gold because its so common...thats why I went with Copper. Have several that are Flat & Glossy Black to switch it up.  When Dan & TLM downsized their office in Bethpage Village, Dan was so kind to donate the 4 Section Burnham Classic Victorian Radiator to my Old Farmhouse..In Matt Jr's room...its kept him warm for 21 Years!  Mad Dog 🐕 

ChrisJ

Mad Dog_2 said:

I purposely didn't want silver or gold because its so common...thats why I went with Copper. Have several that are Flat & Glossy Black to switch it up.  When Dan & TLM downsized their office in Bethpage Village, Dan was so kind to donate the 4 Section Burnham Classic Victorian Radiator to my Old Farmhouse..In Matt Jr's room...its kept him warm for 21 Years!  Mad Dog 🐕 

If I ever get time to do it I'm painting all of mine satin black.

AdmiralYoda

@Mad Dog_2 If I were to show my wife a paint swatch of that copper/bronze she'd puke just because it isn't a color she'd pick for well...anything. But to be honest it is growing on me. We have a similar green paint in our living room with white trim. I think it contrasts nice.

Rather than just ask her about the color I'll just show her the picture. I'll let you know haha.

**edit
Just asked the wife. Nope. Has to be shiny white.... so shiny white it is.

At this point I'm either leaning Benjamin Moore or the VHT Engine Enamel aerosol.

Mad Dog_2

Get them sandblasted first, Chris, if needed (thick, old, crusty layers paint).  They look like fresh Cast Iron straight outta Pittsburgh!  Mad Dog 🐕 

Mad Dog_2

I'm no paint guy nor an interior decorator. I know Flat, Matte or glossy....Satin getting a little high falutin for me..ha ha 😂 🤣 😆 😄 Mad Dog ssy

random12345

@AdmiralYoda We got one of our rads professionally sandblasted, primed and painted with Rustoleum Stops Rust clean metal primer and semi gloss white enamel respectively. The shop did a great job, looks good….but stank for 3 months. I would absolutely avoid the engine enamel for that reason.

Mad Dog_2

Stanky... unless you like that smell...gasoline ⛽ PVC glue...opens your nostrils and sinuses.   Do NOT try this at home, kids...WILL do "Drain Bamage."  Volatile organic compounds.  Nasty stuff...Mad Dog 🐕 

AdmiralYoda

@Mad Dog_2 what paint did you use in those pictures two posts above? I'd be very happy with that finish.

There is a powder coater near us but the problem is sand blasting. No one close at all. There is a mobile "Dustless Blaster" company that will travel to me but I haven't gotten a quote yet. They use high pressure water with some abrasive mixed in and a rust preventative additive.

The powder coater made it clear that they don't do the prep work, aside from a quick wipe and rinse.

Ogg

I used Rustoleum metallic spray cans for all mine. Wire brushed and dusted w compressed air. 19 years and holding. The out gassing can be pretty spectacular, so I’d do them in the summer so they can cure more slowly. But apparently color matters as well. There is a chart of radiant effectiveness according to color somewhere. Maybe The Lost Art of Steam Heating? I was disappointed to find that my color was not that great. Oh well, good luck !

PatrickNorth

I've begun "home bronzing" radiators as I renovate rooms. This example has a Rustoleum "red oxide" primer (I used a spray setup but the same primer is available in rattle cans) followed by a topcoat of good quality linseed oil and mica powder of your choosing (lots of options). Application is pretty much foolproof. I like the matte finish. This one was done a year ago- no problems with it.
Patrick

Mad Dog_2

Outstanding!!  Mad Dog 🐕 

mattmia2

KBS has a product similar to POR-15 that is a higher durability paint and is available in may colors in a rattle can. I would probably skip the zinc phosphate and just use their primer and topcoat and maybe clearcoat if i wanted a particular sheen or more durability. I would only use the zinc phosphate acid bath if the radiator was particularly rusty or was going someplace very damp.

mattmia2

In general you can spray a clearcoat over the color coat to change the sheen if you need to with any paint.

If you have a compressor it will be both cheaper and easier to get a spray gun than to buy enough rattle cans for your project. The gun covers more and is a lot less fatiguing than that little nozzle on the can too.

Jamie Hall

Permit me to mention that all of the spray approaches -- whether spray gun, HVLP, or rattle can -- imply that you can and have either removed the radiator to a safe, ventilated, spray environment, or have completely protected everything in the vicinity. This may or may not be all that easy to do...

Pezdyspensr

A word of warning.  Last year, after reading all the forums that standard issue paint is fine after a quick off-gas, I decided to wire brush and spray paint mine with Rustoleum white gloss.  Now I tolerate questionable activities with relative ease, but the off-gassing was astoundingly horrid, leaving a veil of noxious gas in the air that takes the moisture right out of your throat. The paint would get really soft and tacky at heat. I tried several runs hoping it would improve.  I called Rustoleum and they said they no longer stand by products that can withstand any heat other than the few specific matte options for engines etc. In fact they said it would never fully cure with subsequent heatings. Anyone who has successfully used Rustoleum probably did so 20 years ago, when it was still ultimately an oil-based enamel. These days it’s all plasticized stuff.  Ultimately I took mine to a powder coating company that properly sandblasted.  Plus side is the surface is impervious and super slick, which makes cleaning worlds better than a painted surface.  

hot_rod

Nothing beats a powder coat baked on at 400 degrees. No off gassing, extremely, hard finish, reaches all the small grooves and cracks.
I’ve never heard of a powder coated that doesn’t also sand or bead blast?

New England SteamWorks

Mad Dog_2 said:

I purposely didn't want silver or gold because its so common...thats why I went with Copper. Have several that are Flat & Glossy Black to switch it up.  When Dan & TLM downsized their office in Bethpage Village, Dan was so kind to donate the 4 Section Burnham Classic Victorian Radiator to my Old Farmhouse..In Matt Jr's room...its kept him warm for 21 Years!  Mad Dog 🐕 

Great minds think alike! We also chose copper/gold for our radiators. Also had them professionally sandblasted. Then professionally sprayed with 2-part epoxy paint. Beautiful...