I’m new to this forum,. so I apologize if this topic has been covered previously:
Can’t tell you how many videos I’ve watched where the guy shows us the temperatures on the OUTSIDE of his device using one of the pistol-like HF or other non contact meters.
Just saw one yesterday where the guy is surprised the the temp drops very quickly then increases as he moves from the heat source to the output. He does not notice that that areas that register a higher heat are black and the areeas that beget a lower temp are shiny.
I was going to write a short article to make folks aware of this phenomenon, but I googled around just a litlle and found the following link which explains it a LOT better than I could have: http://www.allqa.com/IR.htm
Not only do they explain what is going on, but they tell you how to easily deal with the situation.
I’d also point out that the instructions that come with some of the meters DO discuss this issue.
Wayne usually uses his hand to check surface temps. I think he’s got an infrared and I don’t know if he’s used it on a video. Since his gasifiers are all black, the readings should be very accurate.
I use my hand, too. But, as a blacksmith, I use the BACK of my hand. That way if you get burnt, you can still get the day’s work done.
Let’s see----
-40 F to about zero: tomgue
zero to about 250 F: hand.
250 to 500: spit.
500 to about 800: who knows? (most dangerous range for humans)
800 and up color of the glow.
Thanks Pete, That was a good chart to work with. Last time I froze my tongue was when I took a propane tank off a torch in 1983 as that was how I used to tell if they were leaking. Big mistake and I had that damn circle on my tongue for months … Can I say stupid ?? I think it was around 20 below and I was thawing pipes and had to put a new cylinder on the torch but I had had previous cylinders continue to leak and fill things up with propane gas (bang) … ML