A Good Thermometer?

[Coal]

Hey guys, I wanted to ask where I can find a cheap/good thermometer that goes to around 1000°C?
Yes I know that's kind of high.. no wait... this is a Blacksmith forum... should be fine.
Anyways, could you guys make any suggestions? I'd prefer one with a needle (old-school gauge style) if possible, but electric is fine.
Thanks a lot!
Also I'm new, so if this needs to get moved then please move it.

-Coal

[Glenn]

Auto supply stores have them for measuring heat on the engines. I have also seen them in Industrial supply stores. Specialty shops have thermometers in a choice of ranges, configurations, contact or non-contact, wired and wireless, etc, but the price goes up with the specs and configuration that you need.

If your specs are loose, within 3-4% of the actual reading, then you can find inferred hand held thermometer for under $50, and less on sale.

[Marksnagel]

Hey Coal,

Welcome to IFI. You've come to the right place to learn. Just ask away.

Mark <º))><

[Dave Hammer]

Axner (Ceramic supplies) has good prices for analo pyrometers. No cheap though.

[Coal]

Awesome. Thanks so much for the replies guys! I found a nice thermometer on Amazon for $91 which is a bit steep but my buddy uses it and it got some good reviews.
I might also go to a car-parts store and pick up one of those engine ones, though. :)

[basher]

you need a type K iconel thermocouple and a reader in the UK the thermocouples cost £30 and up and very good readers cost £15 direct from chine via ebay or more like £150 for a uk one . your prices should be cheaper . these are good up to around 1200 1300C for higher than that you need type R and they are very costy.

[PeterM]

Coal - As Basher mentioned, you'll be wanting a "Type K" thermocouple, but you might look for one rated to F 2100 degrees. 1000 degrees is not for a forge after all! Also, get the ceramic sheaths to protect the probes in that harsh environment.

I run a two burner propane forge and use these, wired into a digital thermometer/PID:
http://cgi.ebay.com/Kiln-Thermocouple-Type-K-w-ceramic-block-/290572021904?pt=LH_DefaultDomain_0&hash=item43a7713090

Mod: notice the poster said they wished a high range of 1000C, which is fine as not everyone is thinking degrees F

[nthe10ring]

I just bought a nice little pyrometer with thermocouple good to around 2400 degrees for 50 bucks new, been working good for me,, spend another 4 bucks and get the longer probe. Bought it from Auberins Instruments online.

Jerry

[Liam Hoffman]

PeterM - Is the Ceramic Probe&sheath required for a coal forge?

[saintjohnbarleycorn]

There are a number of thermocouples and "readers" you can even use a cheap electrical meter to read the thermocouple as it makes electricity milivolt range. Do some more reasearch, ebay, craigs list, they are not that hard to put together, and digital does have its advantages. good luck.

[thingmaker3]

If you or one of your buddies can make circuit boards, try a type K thermocouple, an AD595 chip, and a cheap analog voltmeter.

[Robert Yates]

I use a laser type

[westernironworks]

would the one in my link be a good thermometer for my forge for heat treating? http://www.ebay.com/itm/K-Type-Digital-Thermometer-thermodetector-TM-902C-Thermocouple-Probe-/180852232557?pt=LH_DefaultDomain_0&hash=item2a1ba2116d

[Robert Yates]

Raytek Raynger MX4+ Infrared Thermometer

-25 to 1600°F, 60:1 (D:S), ±0.75% accuracy, laser sight, adjustable emissivity, hard case, datalogging, RS232 PC interface, type K probe
this is one I have been useing it for quit some time.

Sam

[ThomasPowers]

1600 degF is rather low for some of the high alloy toolsteels: example D2: "ramp to Austenitizing temperature at 1790F to 1850F" or A2 "Austenitizing temperature 1720F -1760F". And don't even think of the HSS alloys like M2 "Preheat at 1450 F before heating for hardening. Then heat rapidly from 1450 F to 2200 F and hold for 3 to 5 minutes followed by quenching in oil, air or salt bath."

Of course it's great for steels like 52100, 1095, 5160, etc.

So depending on what you work with the Raytek Raynger MX4+ might suit you fine; or not.

[timgunn1962]

The readout in Westernironworks' post #13 above works very well indeed. The thermocouple probe that comes with it is only really useful up to tempering temperatures though. It's a glass-fiber sheathed bead probe.

The TM902C only reads in degC. I don't find it a problem, but some will, particularly West of the pond.

I have had four of them so far. All give very good agreement with each other and with my other, much more expensive, instruments.

As a probe for checking forge temperatures, I'd recommend an Omega KHXL-14G-RSC-24.

Some details can be found here:

http://www.omega.com/ppt/pptsc.asp?ref=KHXL_NHXL&Nav=tema06

My recommendation is based on my own experience; The KHXL part denotes a typeK thermocouple with a Mineral Insulated "Super Omegaclad XL" sheath, which is claimed to be good to 1335 degC (2440 degF). It certainly seems to survive much better above 1200 degC (2192 degF) than 310 Stainless steel, the only other MI sheath material I've used at high temperatures.

The 14G denotes a 1/4" (possibly 6mm?) probe with a grounded junction. The 1/4" probe is rigid enough to allow it to be placed where it's wanted in the forge; helpful if you are trying to establish the temperature distribution. The grounded junction provides fast response and means that the measuring point is at the probe tip (Insulated junctions slow response and tend to average the temperature over the last couple of probe diameters: 1/2" or so on a 1/4" diameter probe).

The 24 denotes 24" length. It's a fairly comfortable length for most of us. 18" is a bit too short for comfort once the tip is 12" into a forge at 1300 degC (2192 degF).

The probe comes with a length of cable attached, ending in a miniature plug to suit the TM902C and most other handheld readouts.

1300 degC seems a pretty good temperature for pattern welding Carbon steels (I measured the forge temperature at a hammerin after 2 days of constant use making Damascus. The temperature was 1280-1310 degC. Nobody had even hinted that the temperature might not be right). The Omega probe will let you set your forge temperature to the right ball-park for this. It may be too low for comfortably welding mild or wrought, but it's pretty much the limit for base-metal thermocouples. The next step up is Platinum-based thermocouples with ceramic sheaths: very fragile and very expensive..

I feel the kiln-type fixed thermocouples are useful in kilns, or where it has been determined that the temperature at the probe tip is representative of the temperature of the entire working area. For HT they are great. For other things, I'm not so sure. Bear in mind that if the working area is small (eg a small hot-spot under the burner), it might not be desirable to block part of it with the thermocouple.