MTFCA Forum

I have been getting the radiator on my 1914 speedster ready to put back on the car. It is a repro radiator possibly 25 to 30 years old or so. Its a really nice condition radiator that just needs cleaned and detailed. I have polished all day till my arm is about to fall off , but it is looking better. Now I need to paint the core and wonder what is a good choice for the paint. I know it needs to be as thin of a coat as possible. What is the usual choice for brass radiator cores as to sheen. Flat, satin, semi gloss or gloss. Last question is how much of the side towards the fan gets painted. Im new to being a "brass car owner" so I need some help.

click on photo to enlarge

Donnie

Head on over to the Model T parts agency and have them dust off a can of M-122 Radiator Black, that's what was used

For real, just use a paint that is a soft dull black paint, thin, and dries fast. You can put it on the upper tank too. Ford Service says to coat the outside of the fins with black paint. For the radiator don't use heavy thick enamel, and many coats. Gloss isn't to be either, just a dullblack.

Have used Rustoleum Rust Reformer on my core, sprays thin, is a nice dull black, and lasts. While it can prevent rust, it is also a great thin primer, and is high temp resistant too for radiator tanks. Also have used Hi-Temp grill and stove flat black, just spray light coat.

Most times only the face of the radiator is painted as that is what shows, only the external fins and tubes, don't spray deep or thick into the core and try to cover every tube and fin, front and back, that is too much paint that can retard the heat to air exchange that the radiator performs.

Now for your period speedster you could mix up a batch of 'correct' covering for the radiator:

Dyke's 1922 formula:

3 0z. boiled linseed oil; 4 oz. lampblack; 1 oz. turpentine, mix and thin down with turpentine. Dip or spray or place horizontal on boxes and allow the thin mixture to pour over the the parts of the radiator.


And you can get labeled paint for auto radiators from places like Eastwood but they are marked as a gloss paint.

I've used the high temp black for exhaust manifolds on the radiator core with good results. A light coating. I use the rustoleum regular black on the rest. I was always afraid to do too much painting on the core afraid it would act like an insulator and not transfer heat.

Thanks for the info. Ill be going to town tomorrow, so Ill look into the rustreformer or high temp xhaust paint.

Dan, Like all my machine shops in this area, I think the Model T parts agency's owner retired and the new owners (young kids) do not have a clue what M-122 black is. .

My radiator is in very nice shape but it was very, very, very, dirty and tarnished. The funny thing is the fins had a green corrosion just on top of the outside fins. The bottom side of the outside fins as well as top and bottom of the inside fins are really nice and clean. I was able to get most of the green off the fins, now I just need enough "black" to make the remaining green "go away" I do not think Im going to "enjoy" this "polish the brass" thing that comes with being a "brass car owner"

Thanks again guys ....

I like Eastwood's radiator paint. The gloss looks good with shiny brass. The semi I use on later cars.

Dan, smiles for the Dyke's 1922 formula. That mix is guaranteed to get paint smudges on your clothes, hands, and anything else that touches the radiator for many weeks! You can, of course, make up paints like that, and they would be 100% "period correct". That recipe badly needs a shot of cobalt drier, or some other metal salts siccative to be useful.

I researched paints for radiators when I was Fixing mine. The consensus was to use a lacquer paint since it won't hold the heat exchange in. Some paints won't allow good cooling. The nice thing about moving out of Calif. is you can get lots of stuff that hasn't been banned in Kali.
George n Missourah

I agree that Eastwood black radiator paint is your best choice. My T used to overheat all the time until I removed all of the old, thick glossy paint from the radiator and repainted it with Eastwood radiator paint. It has not overheated since. From first hand experience, I would not recommend painting with regular paint. It may look good, but it will severely inhibit the proper operation and purpose of the radiator, which is cooling and recirculating the hot water from the water jacket. Jim Patrick

I favor Rusto-leum products. I have used both their high temp (2000 degrees) & engine paint (500 degrees) successfully. The radiator shouldn't need either need regular finish for at least 200 degrees. Their semi-gloss black may be a bit shinny - start with the BBQ black - it is more of a satin black than a flat or matt black. In any case, for $5 a can you can buy one, test it and then decide.

An old timer I used to know said to use liquid black shoe polish. I don't know if it's still available now a days.

When I was at Brassworks last Friday they told me they use Rustoleum flat black enamel. It's an oil based paint, and not a high temp paint. If your radiatgets hot enough you need a high temp paint you've got serious problems.

Back when I was younger, they used to make screen door paint which was thin. Haven't seen it in years.

Small wonder Larry. No demand. Screen door ?? Like, no AC man ? Wassup wid dat ?!? And the few that are left use . . . plastic screen !

Checked into Rust-Oleum products. Spec on their Engine Enamel -Low Gloss Black- "This durable coating creates a smooth, high-gloss finish that withstands intermittent high heat and resists oil, gas, grease, rust, salt, humidity and solvents. Heat range is up to 500 degrees more than needed. They also suggest multiple thin coats several minutes apart. Their Flat Black enamel didn't mention its resistance to heat and petroleum products. I have found that a thin coat is one that does not completely cover the surface - that's the job of the additional coats. The R factor for paint is 0 and black is the best color for dissipating heat. So as long as you don't plug up the vent holes you should be okay.

The bottom line here is, the more paint, the less heat transfer!

We have always used lamp black it is a powder you mix with solvent and used with a spray bottle we respray the rad every 10 years,the solvent drys and your left with a flat black color and it does not affect heat transfer. I believe this is how it was done in the old days , Dad used it in 1960 our rad is still the original rad Cheers Colin