TOPIC: '57 Merc Refresh

Moe wrote: I thought about getting one of those for smoking ribs but never did. I just use the thermometer in my hand, if I can keep it on the exhaust cover, its cooling, if not, shut her down.

Yeah... that works too. Plus, you never forget to bring it with you.

Locomotion wrote: I found through testing that a strike anywhere match(the type with the white tip, not the all red) ignites at about 450 degrees Fahrenheit. That will give you a reference point.

Interesting. I'll have to try that. I had to anneal a casting of one of those speedometer pitots so I could straighten it, and used a method suggested on another site. If you draw a line on the part with a red 'Sharpie' marker and then heat slowly until the red ink turns brown and starts to disappear, you're then just about at the right temperature. I've used it on sheet too and it seemed to work fine, plus you have a visual cue that you are getting the whole area up to temp.

Probably enough thread drift... Sorry Moe. Carry on.

I thought about getting one of those for smoking ribs but never did. I just use the thermometer in my hand, if I can keep it on the exhaust cover, its cooling, if not, shut her down.

RickG wrote:

Locomotion wrote: I have used high end instruments and they work no better on Aluminum than the very basic units.

Good to know. I don't use the thing a lot, but now I won't be tempted to upgrade to a better one. Occasionally the 'Good Enough Store' actually is.

I bought one with a thermocouple and used it to test a heat gun, I found I had one already that was able to get the 0.062 sheet up to an acceptable range to anneal the sheet with out over heating. Sheet is tricky, castings are not as critical.
I found through testing that a strike anywhere match(the type with the white tip, not the all red) ignites at about 450 degrees Fahrenheit. That will give you a reference point.

Locomotion wrote: I have used high end instruments and they work no better on Aluminum than the very basic units.

Good to know. I don't use the thing a lot, but now I won't be tempted to upgrade to a better one. Occasionally the 'Good Enough Store' actually is.

I have used high end instruments and they work no better on Aluminum than the very basic units.

Rick, I had no idea, that makes a lot of sense. Thanks, that's some good information to know.

It has to do with the emissivity of a reflective surface. From one device seller's web site:

What is emissivity, and how is it related to infrared temperature measurements?
Emissivity is defined as the ratio of the energy radiated by an object at a given temperature to the energy emitted by a perfect radiator, or blackbody, at the same temperature. The emissivity of a blackbody is 1.0. All values of emissivity fall between 0.0 and 1.0. Most infrared thermometers have the ability to compensate for different emissivity values, for different materials. In general, the higher the emissivity of an object, the easier it is to obtain an accurate temperature measurement using infrared. Objects with very low emissivities (below 0.2) can be difficult applications. Some polished, shiny metallic surfaces, such as aluminum, are so reflective in the infrared that accurate temperature measurements are not always possible.

Mine is an inexpensive one too. I imagine higher end devices are better able to compensate for this.

RickG what do you think is happening ? Do you think the aluminum is not transferring the heat?

Those are handy little tools to have in the tool box, just don't expect it to work on mill finish aluminum. The part it told me was only 79 degrees really wasn't when I picked it up.