Since the paint on my roof is toast I have begun looking into black bedliner as an option. I think it would be great for when I have muddy gear up there. It would look cool I think.

First thing ever one says is how much hotter the truck will be. I'm not so sure. So I decided to do a little experiment. Since I don't have any body panels around I decided to use an old license plate as I thought it would be similar in thickness to the roof metal.
Eventually I will go to the junk yard and grab a fender or cut some from a disco roof. I also want to retry the experiment cutting the piece in half eliminating heat transfer. But these results are still interesting.

First I painted half the plate w two good coats of spray on bedliner. I let it dry 24 hrs. I then sat the plate outside in the direct sun for about 2 hrs elevated so as to not have any ground temp interference. Ambient temp was 103 degrees.




The coated side was a balmy 144 degrees directly on the painted surface.




The uncoated side was 115 max. I fully expected this side to be cooler given the black color in the coating




The interesting part was the other side...

I flipped the plate over black is still on the right. It reads 144 degrees. No big surprise there.



The uncoated side was a surprising 132 degrees. Even on the edges furthest away from the coated side.



It would seem the underside of the roof would only be a few degrees hotter with the black coating. I believe the possibility of heat transfer may very well interfering with the temps so again I will cut this in half and redo it just to be sure. I'm not sure what effects if any additional coats will have. I want these results as accurate as possible before I do anything. The last thing I want is more heat inside the truck. I haven't taken the headliner down on one of these trucks so I'm assuming the insulation would serve to soak up a bit more heat.

Any feed back or opinions are welcome.

 

Maybe the reflective surface is messing with the temps the IR thermometer is reading?

A friend of mine had a very cheap ir thermometer he used for nitro powered rc car engines. I tried using it to check my temperature by breathing on it. It said I had a fever of 180° I have no idea what happened. But I could reproduce it easily.

 

Good point. I'll try a light coat of primer or something to eliminate that possibility.

I've never had any reason to believe this one is inaccurate. I suppose it's a possibility.

 

i would think you would need some type of paint on the other side of the plate, right now one side is black and soaking up the sun and the other is shinny like a mirror replecfting the sun.

 

and, yes,...the bare metal will mess up the IR aspect of your temp gun. paint it a color similar to your roof's current color, cut the plate in half.

BC