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Advice for painting a CSF radiator?

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Old 11-11-2020 | 06:05 PM
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Default Advice for painting a CSF radiator?

Does anyone here have some experience with this? SEM Trim Black paint seems to be the best color match to OEM but I'm not sure how much "tolerance" it has for application to a heat-soaked item like a radiator. Maybe a special primer is needed?

I assume the shiny aluminum should be scuffed up a bit as well to promote adhesion?

I found this as well though I've never used it. https://www.eastwood.com/ew-radiator...in-finish.html

Thanks.
Old 11-11-2020 | 07:05 PM
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I would use light coats of SEM self etching primer followed by SEM Trim black. It'll be fine at radiator temperatures.
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Old 11-12-2020 | 05:51 AM
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Appreciate you might be wanting to keep the look as close to stock as possible but I would be somewhat wary about trying to paint a radiator finned core when it must be nigh on impossible to control paint distribution on the extended surface fins. Clearly they are paintable. For sure if I were to undertake something like this I would be seeking procedural assurance from someone who has attempted such successfully in order to ensure one does not wreck the thing. On the other hand I am biased as I have had an aluminium radiator for 16 years but then originality means squat to me - I am very much "function over form".

Rob has covered the primer type. If you do go ahead kindly post some pics and procedural details.
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Old 11-12-2020 | 02:43 PM
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My Big Concern about multiple paint layers is interfering with heat transfer. I think you want the thinnest possible paint film on radiating surfaces. Go to town on the support frame and all, else a satin finish barbeque paint would get the nod if it passes the finish-quality tests on a test panel.

My '89 has a black radiator and frame from the factory. I've seen numerous cars that have unpainted radiators. The radiating portion is hidden by the AC condenser and ATF cooler in the front, and by the fan console and fans in the rear. I have a NIB NBO Behr radiator in attic storage, and no idea if it's painted or raw aluminum. If it goes into service and it's raw, I suspect it will get only the support frame painted, plus a little around the corners into the finned area. Just the parts that are visible while installed. We live in a dry desert climate, as has the car its entire life, so no concerns about salt or other corrosion on raw aluminum fins or tubes. Your conditions and needs may vary.
Old 11-12-2020 | 03:35 PM
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Thanks folks. Lots of great info and insights. I agree with the notion of the less paint, the better. I think that my current plan will be to just paint only the exposed/viewable surfaces such as the top, sides and bottom.

My current rad still has the original foil decals so my next task is to see if I can carefully remove and reuse those instead of buying new.
Old 11-12-2020 | 04:08 PM
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I woud not paint it, unless you can bake the paint on. Even then I bet after a few years it will fake off.

For the stickers heat them up with a hairdryer and try using dental floss to break the adhesive. If you bend them at all they will get damaged. Or just call Roger and get reproductions.
Old 11-14-2020 | 08:33 PM
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FWIW, this might be something to consider: I painted my radiator with a rattle can of either a Krylon or SEM paint (too long ago to remember which...), and the next time I tried to remove the hoses I found that they had bonded themselves to the radiator. I tried the usual methods, but ended up cutting both of them. I certainly had not used any sealer, but maybe I had not allowed the paint to cure well enough.
Old 11-14-2020 | 10:37 PM
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The nozzles are on the plastic tanks, so they would not get painted as far as I know. scratches head... There are some interesting old school hose removal tools that look like mini hay-bale grabbers. The shaft has a bend in it with a bit of a curl, and sharpened so you can wedge it at the end of the hose and twist to get the sharp end between the hose and nozzle. Drag it around the nozzle to break the bond, and the hose slides off easily in a few seconds. Don't scratch the plastic nozzles or risk a leak.
Old 11-14-2020 | 10:59 PM
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A layer of flat black will dissipate the most heat...supposedly better than bare aluminum.
And Wurth makes fantastic paint, which has a ton of solids and sticks like mad.
Old 11-16-2020 | 12:56 PM
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Dr. Bob - My radiator is all aluminum, no plastic. I have one of those weirdly bent tools which I have used successfully on other cars and it works well if there is room for access, but I was unable to work it completely around either nozzle and the untouched area was sufficient to prevent the hose from releasing. No twisting, pulling, or otherwise appropriate swear words worked, positioning the tool was awkward and I was concerned with gouging the nozzles, maybe I could have reshaped the weird tool or even made a new one that could be negotiated around the nozzles, but cutting the hoses was the easiest and quickest solution even if it did seem like something of a defeat.
Old 11-20-2020 | 12:56 AM
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Let us know how this turns out. I suspect that I'll be replacing the radiator in mine soon, and also would like to keep everything looking stock. I agree with just painting the visible top & sides, and not the core.
Old 11-20-2020 | 06:28 AM
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As a hobbiest / enthusiast I would try to replicate a factory process. Lots of great info on the process BEHR uses can be found in the link below.

Heres what I would do.
1. Clean the rad chemically. Behr would have dipped it in a solution bath. In a home/shop low volume situation I'd use spray on wheel cleaner which will rinse easily and leave a nice finish on the bare alu.

2. I'd hang up the radiator and spray paint it with a 2 part urethane semi flat black. Many automotive paint stores now have 2 part paint in a single can. You pull a tab and mix right before use and you have 15 min to complete the spray.

Using wheel cleaner on bare alu needs to be rinsed well and I just used this process on some alu spindles on a Audi S8 that had lots of grime. The finish was extremely durable and looked great even after the machinations of reassembly and installation.

https://finishingandcoating.com/inde...-tier-supplier
Old 05-31-2023 | 04:07 AM
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Hello, have you used this product before, and what were the results? Currently, my radiator is in poor condition, and I would like to repaint it, but I have never done it before. I have already found a radiator-paint online, but I'm not sure about its effectiveness. I would like to make the best choice possible. If you have any other suggestions or available options, I would appreciate them. Thank you in advance.
Old 07-03-2024 | 11:02 AM
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Default Radiator heat resistant black paint match?

Anyone ever color match the black paint on the radiator and surrounding parts?
Is a engine/heat paint required?
I want to touch up the area and it becomes apparent there are several shades of flat black let alone engine/heat tolerant paints.
there is some mention of Wurth paints above but which color black?


(not actual photo - for illustrative purposes only)
Old 07-03-2024 | 11:09 AM
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I have a CSF radiator in my car...I would not recommend painting it.


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