Pulled the radiator to plug some holes. Thought it could also use some paint. Can I use regular high temperature paint vs the "specialized" radiator paint? I just need to spray the header / bottom; but also think a little spray on the fins help protect from rust.
A radiator will never get hot enough to need "high temp" paint. And I have no idea what could possibly be special about "radiator paint" other than marketing.
A radiator can not rust. It is either brass (OEM) or aluminum or some combination of plastic and aluminum.
Any paint on the fins will, to greater or lesser degree, degrade heat exchange and effectiveness of the radiator.
A lot of times brass or aluminum need to be etched for paint to adhere well. There are chemical ways to do it, as well as etching primers. Perhaps that is the difference with a radiator specific paint?
I when bomb canning generally use a high temp gloss black. That’s what OEM was basically.
If you don’t want the black paint flaking off in like 2 years, clean the s*** out of it and get it good and dry. Then first hit the bare brass with some self etching primer, then a top coat of a sandable primer all over, then your black paint.
Possibly the special radiator paint has to do with heat transfer. That is the purpose of a radiator is to transfer heat generated by the engine into the air crossing over it.
I have read where about 80% of the heat transfer is convective and 20% is radiated. Black radiates best but anything you put on the fins will tend to insulate and reduce convection. The radiator shops I have used always paint them gloss black after re-core.
I’ve used the high heat spray in cans or quarts on my smokers and it holds up very well even on 600 degree cook chambers and fireboxes. I like @charliemeyer007 have always touch up a radiator using plain old black satin
