infrared themometer

C

cjd1980

Joined
Sep 3, 2008
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i 'm looking at possibly geting one to check steel temps until i can get a oven for heat treating anyone use one or recomend on thanks chris :)
 
For checking low end cycling temps, as in normalizing, they're very
useful. They also work well for checking tempering temps, and quenching
oil temps.
Most will max out at 1000 f. or less, and those that will read higher accurately,
will probably cost more than a good pyrometer/thermocouple set up.
 
You can buy a thermocouple off of fleabay then get a cheapo $25 Multimeter from HF, it comes with the thermocouple module. It'll read to 2000 F.
 
hope i don't sound to stupid but how do i use a themocouple does it go in the forge or can i get the temp of the metal with it thanks chris :)
 
The thermocouple end goes in the forge, 2 wire leads go from the thermocouple to the module on the multimeter. I think it's more important to know the temperature of the forge interior than the metal. You know if you just get a decent soak (at a normal cross section) that the blade temps should be right.
 
cjd1980 said:
hope i don't sound to stupid but how do i use a themocouple does it go in the forge or can i get the temp of the metal with it thanks chris :)
Click to expand...

Position the thermocouple so that it reads the temperature you want the steel to be then heat the steel until it is the same color as the thermocouple.

I think Russ was trying to hint that IR thermometers won't work for HT'ing steel because they don't read high enough temps. You can find one that will read 1600+ F but be prepared to grab your ankles to pay for it.
 
thanks guys i'll start looking at themocouples instead and see what i can find thanks agin chris :)
 
Probably the best thing to use for HT in a forge is a pipe muffle. A heavy steel cylinder open on one end where you put the knives, I made mine with a small hole in the top so I could use my thermocouple inside it. That way there's no guessing. You still have to watch the colors to see when the steel is up to temp and count soak times, etc.
 
69_knives said:
Probably the best thing to use for HT in a forge is a pipe muffle. A heavy steel cylinder open on one end where you put the knives, I made mine with a small hole in the top so I could use my thermocouple inside it. That way there's no guessing. You still have to watch the colors to see when the steel is up to temp and count soak times, etc.
Click to expand...

Wouldn't the thermocouple probe still be affected by the heat outside the muffle?
 
Troop said:
Wouldn't the thermocouple probe still be affected by the heat outside the muffle?
Click to expand...

The thermocouple I used for this measures resistance across a tiny ball of metal at the end of the wires, so it is only affected by the heat at the very spot where that ball is situated.
 
69_knives said:
The thermocouple I used for this measures resistance across a tiny ball of metal at the end of the wires, so it is only affected by the heat at the very spot where that ball is situated.
Click to expand...

So, it's tip-sensitive? What brand is it? I wonder if my Omega is also tip sensitive.
 
At the moment I'm just using the one that came with my multimeter. It's a "K" type, there are several different styles and types.
 
Your thermocouples are tip sensitive. Thermocouples rely on the "Seebeck Effect" where the juction point of two dissimilar metals will generate a small temperature dependent voltage. Just make sure that the insulation on your thermocouple wires is not damaged or you may be reading the temperature of a point that is not at the tip. You also have to connect the proper wire to the proper terminal of your meter. Otherwise, you will get reall crazy temperature measurements, even at room temp. If you need an extension, you have to use the same type of wire used in your thermocouple.

Phil
 
ok i looked around a thremocouples but i don't really know what i want or how to hook it up to the multi meter also i m worried about the wires getting bured up or damaged inside the forge sorry for being so damned needy but i'm not very technily minded so thanks for the help and please bear with me thanks agian chris :)
 
My setup I spoke of earlier worked fine with my firebrick forge but now that I'm building a new pipe forge, feeding the wire down the little hole in the pipe muffle won't work so I just ordered a couple of 12" thermocouples, that should give me enough flexibility to just stick the probe in the pipe muffle from the front of the forge and have the thermocouple hooked up the the PID even if only to read the temp... I'm kinda leaning toward burning waste oil so I don't know if the PID will control the forge or just read temp for HT at this time.
 
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