push rod tube, to paint or not Options

[jacksun]

Hi,

got my first push rod tube cleaned up and would like to paint it with

hi-temp paint? any problems doing so?

tks

randal

[stugray]

You're talking about the point in that video, right?

Yes, and it also applies to this discussion.

1 - Yes black paint will help the push rod tubes radiate heat better (but they will also absorb heat better)
2 - The black paint does not change the convection properties at all (positive or negative) contrary to your comment:

"Bare metal (aluminum anyway) convects heat best, and that's science"

Although the truth is that certain surface preparations DO help convect the heat better if it increases surface area and does NOT provide an insulating layer. An aluminum flame spray coating would help convect heat better than a polished aluminum surface.
A rough plastic coating would HURT the convection because it would decrease conduction of the heat to the surface where the convection takes it away.

3 - The emissive properties of the tubes (painted or not) is meaningless because the contribution towards cooling is orders of magnitude greater for Convection than it is for Radiation.

So trying to optimize convection is a much greater return on investment than optimizing radiation.

[Keyser Sose]

In the video you posted the black paint really improved the heat transfer from radiation, but in this or that application who really cares about radiation?

2 - The black paint does not change the convection properties at all (positive or negative)

Yeah, funny thing, I went back to look at the Mighty Mods video you posted and bless my soul if among the "you might also like" videos shown there's this one, "Mythbusting the Mighty Mods Black Intercooler Video" with an engineer going through the math and apparently contradicting both the conclusions in that Mighty Mods video and some of your points:

http://www.youtube.com/watch?v=z_mmmXTbLP0&sns=em

Those are twelve minutes of your life you'll never get back, but it seems better than going back and forth about it. In any case this horse is truly dead now, so to the original poster my advice is to ignore the science, ignore the conflicting advice and do whatever the hell you want.