Painting hardtop underside black (with bedliner spray)

[Gecko-JKU]

Let's suppose that a JL/U owner hasn't purchased the MOPAR headliners with the rig, and they want to do this and have Hot Head Headliners.

Can it be done? What's the procedure/order of things? Will the headliners adhere to the painted surface? Would it be better to install the headliners first, mask them off, and then paint around them?

The Hot Head Headliners are fairly simple for installation. It uses the 3M sticky tape so I imagine it will stick just fine to the Line X or spray can. If you want to get really fancy you can coat with automotive soundproofing sheets, then paint, then cover with the hot heads to seal it all up nicely. Hot heads sends their equipment out with a little roller to really get the 3M tape to stick well to whatever surface you put it on.

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[Vegas_Sirk]

I met with Line X yesterday, We went over the whole project and he suggested their product know as Line X Ultra, it's not as thick, hard and has a nice, more glossy finish. We are in planning phase, and owner wants to do on a Saturday, (no other vehicles around). The price you ask.....? Well, he gave me a range between $500 - $600 (about the same as Head Liners). That's for everything prep, primer and Line X Ultra. So hopefully we will get it scheduled soon, with this weather MD is having next month is most realistic.

Cant wait to see how this turns out.

 

[theplankeye]

Some of you may not know that black not only absorbs light extremely well, but radiates very well when hot. You will have higher interior temps due to this mod.

 

[Rubi-Zero]

Some of you may not know that black not only absorbs light extremely well, but radiates very well when hot. You will have higher interior temps due to this mod.

The outside is already black. The interior color has nothing to do with temps.
The outside surface is going to get hot no matter what color it is on the interior, this alone will transmit the heat.

If two Jeeps were sitting side by side in the mid summer sun, you believe a white interior top is going to be cooler to the touch on the inside then one painted black on the inside?

 

[theplankeye]

This is basic thermal science. There is no controversy in my statement and a philosophical argument does not make the issue go away. What happens is the top gets hot from the sun. That heat transfers to the inside surface easily through the plastic because there is no insulation. The inside surface is very hot. That hot surface emits infrared and spreads the heat to everything else. There is a reason it is white inside unfortunately. Black surfaces are excellent emitters of IR, white are poor ones, which is an advantage for uninsulated interiors like ours.

 

[Rubi-Zero]

This mod will not make your Jeep any hotter then the next for it to even matter.

Sure that’s why Jeep decided not to paint the inside of the tops.

If it’s warm out, the top should be off anyways.

Painting the inside of your top now makes it warmer in the winter.... cool

 

[theplankeye]

Good luck my friend! Hahaha

 

[Rubi-Zero]

Thanks but no luck needed... I had this done for years without cooking myself to death. I also did my brothers top and he too, has had it painted for over 7 years like this without problems of dying from over heating by the inside of the top being painted black.

 

[Vegas_Sirk]

The black paint while true its a heat emitter, wont affect the area enough to make that much of difference. Also with it being on the inside of the top it wont be getting direct sunlight and therefore will not be absorbing the heat for it to emit in the first place.

 

[Dynomite1371]

Some of you may not know that black not only absorbs light extremely well, but radiates very well when hot. You will have higher interior temps due to this mod.

I can add some color, it will probably bump the price though but I did think about that. But I don't think it is a real concern. I can guarantee you that, if jeep painted them black very few of us would be out there painting them white due to heat issues.

 

[theplankeye]

The black paint while true its a heat emitter, wont affect the area enough to make that much of difference. Also with it being on the inside of the top it wont be getting direct sunlight and therefore will not be absorbing the heat for it to emit in the first place.

It’s not hard to understand. The bottom surface receives heat conducted from the top through the thin plastic. Touch the white ceiling on a hot day. Plenty of heat energy there to send out some serious IR.

 

[dudemind]

All else equal, a black surface will emit more heat compared to a white one. That's thermal dynamics (read up on thermal emittance).

However, this is going to be very much muddied in practice, due to the "all else equal" condition. The surface material also factors into the equation, and without actually testing it'd be tough to say whether a bedliner-painted ceiling would in fact emit more heat. In fact, it's possible that the physical properties of bedliner make it a worse emitter of heat than the surface from the factory, and further that this difference overcomes the difference in color.

Furthermore, one must factor in the thermal conductivity of the bedliner itself. Even if we assume that the surface properties of bedliner are exactly equal to the factory white material, the heat has to first be transferred to this new layer, and it's an unknown how well that transfer happens. This is in fact exactly how the headliners manage to reduce internal heat, despite being black. Sure, foams are have incredibly low thermal conductivity due in part to their porous nature, but there are plenty of non-porous materials that exhibit similar characteristics (many fabrics, rubbers, oils, woods). It isn't entirely unreasonable to think that some bedliners may behave this way as well, though without the data I'm going to stop short of making any actual claims.

Another final factor: the bedliner will add extra volume through which the heat energy can be dispersed. This might (and probably does) raise the net thermal capacitance of the top on average. How this ultimately factors into debate is, again, an unknown.

In the end, how any of this changes the amount of heat we're likely to feel sitting in our cars is not so black or white. See what I did there?

 

[timkim]

Thanks but no luck needed... I had this done for years without cooking myself to death. I also did my brothers top and he too, has had it painted for over 7 years like this without problems of dying from over heating by the inside of the top being painted black.

i wish i have brother who paints my hardtop too.

 

[halw9000]

Okay. okay... but here is the real question. Which looks cooler?? Black, white, white w/ black headliner....black w/ black headliner?

 

[alex_a2012]

TheRealTVGuy utilized Plasti Dip on his hardtop. The product claims to be insulating (not sure about temps) but his pictures look great!

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