Thermometer Question

[fordfan]

What would be the best way to test my thermometer to see if it is showing a true and accurate reading? When I stick it in the molten lead the needle jumps and jerks as it starts to climb and when it is sitting on the bench for a while lets say overnight like after a casting session, I would think it should be reading room temp and it does not, any ideas thanks.

[dragon813gt]

Glass full of ice with water in it. Let it sit for a few minutes. Temp should read 32 degrees.

[slim1836]

Glass full of ice with water in it. Let it sit for a few minutes. Temp should read 32 degrees.

But that's at the other end of the spectrum, I'd try it in boiling water just as it's beginning to boil, to see if it's at 212.

[fordfan]

Thanks guys I'll give both of these a try. If it is off do I get a new one or can they be adjusted some how?

[John Boy]

If it is off do I get a new one or can they be adjusted some how? Depends on the thermometer. Some like the Tel-Tru's the hex nut can be rotated to set the dial at the correct tested temperature while in the water.
Here's a write that explains the process fully with pictures
http://nfsmi.org/documentlibraryfiles/PDF/20080215082829.pdf

[fordfan]

Thanks John Boy that will help alot.

[Naphtali]

Please note: 212- and 32-degree benchmarks are correct only at specific altitude. I'm confident there will be a reference site that will identify benchmark temperature adjustment for your altitude.

Hope this helps.

[fordfan]

Well I guess its time for a new thermometer I did the cold water test and set the dial to 32 and when put in the boiling water it would not reach 212. And when adjusted to 212 would not go back down to 32 when put back in the cold water. Could someone send me a link to or for a good thermometer.

[warf73]

What thermo are u using? Mine doesn't read below 200F. My next question would be how accrate would a thermo be that can range from 32F to 1000F? If you can find one that is accurate in that heat range I couldn't imagain the price of it.

[fordfan]

http://www.midsouthshooterssupply.com/item.asp?sku=00036MTH1000

[milrifle]

It is my recollection that most instruments, be it a thermometer, pressure gauge, voltmeter, whatever, are most accurate at mid scale. Assuming this is true, calibrating a thermomter capable of measuring near 1000 degrees or so, at 32 or even 212 is only assuring it reads accurately at 32 or 212. It doesn't mean it reads accurately at 700 and could actually introduce more error at 700 than before. Ideally, you would calibrate it at the temperature you will be using it at and just live with the minor deviations it may have above and below that temperature. Of course, actually getting it calibrated at the desired temperature is another story.

[Dave Bob]

http://www.bbqfans.com/products/tel-tru-lt225r-big-green-egg-kamado-replacement-thermometer

Try this one.

Dave

[dragon813gt]

While most are accurate at their midpoint. There are plenty that are accurate across their entire range. They do cost more money. But we're only dealing w/ lead temps so pinpoint accuracy isn't necessary. There is no way I'd trust a voltmeter that wasn't accurate across its entire range. My life depends on one at work