Temperature of cauterization?

I don't know the temperature, but I can see where such a device would get hot due to inefficiencies, yet I wouldn't say it's caused by "the friction of laser fire against the metal of the gun." That's surely (part of) what causes the heat of a barrel of a conventional gun as the bullet passes through it, but there's no "friction" from light, or anything I can think of that would generate it within a "laser pistol." I'd just call it laser diode heating. And of course the laser diode is made of some (currently fictional) high-temperature semiconductor.

And since the barrel gets that hot, it should have as "stock equipment" a shield over the barrel, a thin-walled metal tubes with holes in it (like the shield over a motorcycle muffler or an electric heat gun) so in normal use the user can't accidentally burn himself on the barrel. Your bad guy has of course removed this shield so he can conveniently burn his victim.

It occurs to me this temperature would be above the boiling point of water, and to demonstrate this the character could dip the end of the barrel into a cup of coffee or water, or into the top of a fishbowl which would then hiss with steam, demonstrating the barrel's high temperature. This should be effective enough in showing "this is gonna hurt bad when I touch it to someone's skin."

The Lonely One said:

My character is trying to explain how after firing a laser pistol, the barrel is hot enough to cauterize skin within two seconds of contact (consequently a method he uses to get information from unwilling sources). What's the temperature required to cauterize skin that quickly? I was thinking similar to a branding iron's temp? Would that be unrealistic when referencing the friction of laser fire against the metal of the gun? Hmmmm.

Suggestions welcome.

Click to expand...

MC excitedly explained to Newbie, "after firing a laser pistol, the barrel is hot enough to cauterize skin within two seconds of contact."

"How hot is that?" Newbie asked.

MC called across the room, "Hey Doc, how hot does it have to be to cauterize a wound?"

Doc shook his head in disgust while searching the cabinets and announced, "Don't try to cauterize anything. You will do more damage than the original wound if you don't understand the science behind it." He resumed searching for some hydrogen peroxide and could be heard mumbling, "...size of arteries, tissue necrosis, infection, necrotising fasciitis. If I'm wounded, just give me a bottle of good scotch, some bandages and maybe a splint. Don't let MC near me when my time comes. I'd rather not go out being tortured by the likes of him.."

"But how hot does it have to be?" MC insisted.

Doc turned around and replied in a dejected manner, "That depends. There isn't a single temperature. Are you cauterizing a paper cut or a stump of an amputated leg?"

The Lonely One said:

Ah, here might be my problem: am I using the wrong language? The MC isn't cauterizing a WOUND. He's at a temperature which allows branding, like a branding iron, from the barrel (or is it the muzzle? the circular tip of the gun is what I'm referring to). Sorry for the confusion. How about, "what temperature is required for branding skin?"

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Oh, is that all you want, like a ranch branding lifestock? Glowing red should be hot enough.

Livestock branding irons operate between 600 and 800 degrees Fahrenheit. 500 degrees is about the temperature which body modification artists use for human branding.

Hot water heaters are set at 120F because it is very possible to scald at temperatures higher than that. The higher it is over that, the longer the contact and the larger the surface area, the more likely that a burn bad enough to leave a permanent scar will happen (That's partly why immersion burns are so bad, they have a high surface area and are circumferential). If you have a pot of boiling water and a metal lid which you pick up without a glove you can get a third degree burn and that is only 212F at one atmospheric pressure. So if your laser pistol has a heat shield such that only the tip of the hot barrel is accessible (or the battery casing or whatever gets hot), even if it is only 150F degrees, he could use it to inflict pain. Most of the burn patients I saw had had hot grease spilled on them and that's typically around 350F. It is reasonable that you could have a weapon get hot enough to burn skin without burning up the weapon itself.

In the American Civil War there was a union soldier who got the Congressional Medal of Honor for urinating on his rifle. His unit was cut off and surrounded. They were firing so fast and often that the barrels were heating hot enough to flash the powder as soon as it was poured into the muzzle so that they couldn't load. When they ran out of water to pour over the barrels, he peed. Others started doing it too and they managed to stave off capture long enough for reinforcements to arrive.