Flat Black barrels

[Pete Wass]

I am wondering if anyone has found an advantage to coloring their barrels black. I know the motorcycle industry has always had balack exhaust cpmponents on race bikes and some street bikes, the theory being they disipatse heat better. I have considered painting mine with Brar-B- Que paint to see is it helps. Whadda ya think?

 

[Dave B]

My vote

Pete, I think you have too much time on your hands. Are your barrels really getting that hot?

 

[glp]

Pete...

I am wondering if anyone has found an advantage to coloring their barrels black. I know the motorcycle industry has always had balack exhaust cpmponents on race bikes and some street bikes, the theory being they disipatse heat better. I have considered painting mine with Brar-B- Que paint to see is it helps. Whadda ya think?

give it a try. I have some good pait stripper and you are RETIRED! I would even drink black coffee if I thought it would help.

 

[Cheechako]

Pete

Good question. I asked the same thing a year or two ago and got differing opinions (What else would you expect from Benchrest shooters?) Some said the heat would dissipate, others said the heat would be trapped. Take your choice. I left mine alone and I still shoot lousy, so mebbe I shoulda painted it.

Ray

 

[Dave Short]

Pete,

I'm a little jealous; I'm not sure what I'll do with my time when I retire........but you have me thinking about it now.

I guess I'll have to start packing a heat shield now, so I can put it between me and your mega-heat-dissipating barrel.

-Dave-

 

[mks]

I am wondering if anyone has found an advantage to coloring their barrels black. I know the motorcycle industry has always had balack exhaust cpmponents on race bikes and some street bikes, the theory being they disipatse heat better. I have considered painting mine with Brar-B- Que paint to see is it helps. Whadda ya think?

Pete,
It depends on the barrel temperature, ambient temperature, wind speed and a number of other minor parameters. First, the emittance of the barrel surface is increased from about 0.1 for bare steel to over 0.9 with flat black paint, so radiation heat transfer is increased by about 9 times. But for typical conditions with even a small wind, convection heat transfer is so much larger that radiation heat transfer is still small by comparison.
Radiation heat transfer is also proportional to the difference in the fourth powers of the absolute temperatures of the barrel and ambient, while convection heat transfer is proportional only the the difference in the temperatures. So radiation heat transfer grows more quickly as the temperature difference increases than does convection. If you are shooting indoors (no wind) and your barrel is glowing red (high temperature difference), then paint would make a difference. But not for typical outdoor conditions for relatively slow fire benchrest matches.
Second, the insulating effects of the layer of paint will trap heat in the barrel, thereby decreasing heat transfer by the convective pathway and offsetting gains in the radiation pathway.
Third, if you shoot in the sun, paint is a definite disadvantage, since it increases solar gains.
Bottom line, if you shoot in the shade, go ahead and paint. It won't make much difference in how your barrel cools, but think of how it will have your fellow shooters running to Home Depot when you outshoot them!

Cheers,
Keith

PS: Motorcycle exhaust gets very hot, so flat black surfaces have the potential to increase radiation heat transfer. But motorcycles also go fast, increasing convection heat transfer. Black exhaust is probably effective at idle, but cosmetic at speed.

 

[mike in co]

ahhh an area where i know a little.....this could be dangerous.

A THIN coat of flat black paint will assist in heat dissapation. the operative word THIN. so not likely to be that heavy bbq black.
thick heavy paint insulates.

this is from my air cooled automotive days.

mike in co

 

[Pete Wass]

Thanks MKS

Now we know "The Rest of the Story". I always figured that if one doesn't know, one should ask.

 

[Bob Kingsbury]

Pete, you should put wheels on your LV. Little ones in front and
big ones in back so it looks like a funny car

 

[David Apple]

heat transfer

Studness,

Get your barrel ceramic coated. I just had my headers done and the rap is that it keeps heat inside and is transferred that route. All of the top dragsters use this coating for some reason....

Just a note: The side pipes still get hot enought to permanently scar.

 

[Ernie]

I am under the impression that that metal of any nature heats up quicker than it cools off. Black does def get rid of heat faster....thats a given. As a "added" bonus.......it gives a low-budget look

 

[alinwa]

I am under the impression that that metal of any nature heats up quicker than it cools off.

Is this actually true? I've got no dog in this fight, just an interested observer. It would seem to me that energy transfer would be a two-way street barring insulation qualities of the coating and other extra-terrestrial stuff. If I were to darken a barrel for heat dissipation I guess I'd try sandblasting it and coloring it black with a salt solution like bluing.

al

 

[mike in co]

Studness,

Get your barrel ceramic coated. I just had my headers done and the rap is that it keeps heat inside and is transferred that route. All of the top dragsters use this coating for some reason....

Just a note: The side pipes still get hot enought to permanently scar.

the ceramic coating would be on the INSIDE, to keep the heat from getting to the metal.

 

[John Kielly]

Years ago, Nev Madden here in Australia used to finish his barrels with a V tool cutting what was essentially a fine thread on the barrel. His argument was that it gave the barrel more than twice the surface area for the same bang to help heat dissipation. Then we got impressed with matt linished finishes, bead blasting & whorehouse stocking patterns....

 

[David Apple]

ceramic coatings

the ceramic coating would be on the INSIDE, to keep the heat from getting to the metal.

Mike,

Actually the headers are coated on the inside and the outside.

 

[henrya]

whorehouse stocking patterns....

That's what I'm going for next time.

 

[j mckinnie]

I believe the ceramic exhaust idea is to have a smooth surface on the inside to give better flow of the gasses nothing to do with heat transfer or insulation

 

[Dave Short]

I believe the ceramic exhaust idea is to have a smooth surface on the inside to give better flow of the gasses nothing to do with heat transfer or insulation

Not true.
It is intended to keep the heat in the exhaust gasses for better scavenging effect. It also helps keep the temperature down in the engine compartment.

-Dave-

 

[alinwa]

Years ago, Nev Madden here in Australia used to finish his barrels with a V tool cutting what was essentially a fine thread on the barrel. His argument was that it gave the barrel more than twice the surface area for the same bang to help heat dissipation. Then we got impressed with matt linished finishes, bead blasting & whorehouse stocking patterns....

So I'm confuse....

So were you having your stocking work done by a local brothel??

Or was the whorehouse just stocking the patterns?

Or were whorehouse stockings somehow slipped over the stocks?

Or did you just spell it wrong, were some of ya's whorehouse stalking???

Is THIS where ya's got the idea for the ribbed barrels??

We need clarity here........


al

 

[Charles E]

Uh, Al, this is sort of off track, but shouldn't your little logo be "often dis'd moderator" now? Maybe Wilbur took a look at my ignore list & felt that no matter how dis'd your member, we needed extra help?