Laser Thermometers?

[kappy]

Would using a laser thermometer be a good idea for casting? I figure I could get a better read on my lead and my mold.

[ReloaderFred]

They don't work well at all, in my experience. I have one and the best it will show on the molten lead in my pot is somewhere around 400*. My casting thermometer reads 725* for the same melt. I've read that you can float something on the melt that will reflect back and give a better reading, but I tried several things and none of them worked as well as dipping my casting thermometer into the melt. I couldn't even get a good reading off of the side of my 50 pound pot with it.

Hope this helps.

Fred

[Stampede]

Laser/Infra Red thermometers won’t work good (are not reliable) with lead, at least when it comes to regular (affordable) hand held thermometers.

I do sell these kind of thermometers professionally/daily and I did and do test them rigorously for many industrial companies. Only the high end (industrial) IR-Thermometers will do the job but they will surpass most private budgets by a couple of hundred even thousands of dollars.

It’s the way they (the regular budget thermometers) operate, in essence the reflection of a shiny object, like melted lead, will drastically (negatively) effect the readings of these thermometers. It’s officially called an “Indication” thermometer/reading/registration, in some cases this is just fine but for accurate readings you need a thermometer with “direct contact”.

The more an object shines the less reliable it is. For an acceptable reading you need to apply/use this kind of thermometers according to very specific instructions. The average deviation is plus or minus 1°F to 8°F per 0,5" distance (within 12" distance of the object). Most manufactures don’t mention this. Therefore most industrial applications/control situations don’t allow the use of these kind thermometers.

Again they are not bad (quality wise) but they have their limitations, molten lead is just one of those limitations.

Peter (Stampede)

[Baja_Traveler]

Stampede hit the nail on the head - they are only good for mundane things like measuring AC register temp or electric motor temp where access is limited. In my industry (pharmaceutical and biotech) the AC guy is the only one in the plant that has one, because the accuracy is gawd aweful for the rest of us.

[shooter93]

Wonder if they would work on the mold itself, once you had the mold at a good casting temp could you use it to help maintain that temp? It may not read a perfect degree but maybe in a close enough range?

[GP100man]

I tried mine on a Lee 6cavity & it`s even shiney enuff to not read rite !!

I believe the readings on my Lyman steel molds though.

[Mike W1]

I'm pretty sure when I read my Lyman moulds that the temperature is quite a bit below what I'd expect it would be. Wonder if a person painted a section of the mould flat black if that'd make any difference. And I didn't realize you had to be within 5' or less to get any better accuracy. Always learning something on this forum!

[Stampede]

IR-thermometers work on the principle of reflection and each and every surface react different. For official calibration/testing of this kind of thermometers a very specific black painted box is used. This directly give you an idea that any kind of shiny object won’t read accurately.

These kind of thermometers are all so much used in the food industry. When I see someone use a thermometer like that in a store or warehouse I don’t take them seriously (I even dare to call it: extremely doubtful). A good example is the packaging of lets say meat, the plastic wrap reads differently than the paper pricing/product sticker. The air inside reacts like a buffer and the meat it self has all so a different temperature. And if there is some kind of shiny material like frosted surface and/or aluminium (very common in the food industry) your readings are completely useless. I do produce and sell the normal PT100 or Thermocouple (food) temperature sensors to the Dutch, German and Belgium governmental food and health departments by the hundreds just because the inspectors need to have an accurate and reliable measurement instrument. The same can be said in the pharmaceutical industry like Baja-Traveler mentioned.

All so the distance between the object and the IR-Thermometer like I mentioned before has a tremendous effect. I know a company who used it with a molten aluminium mixture in their foundry, they wasted about 30,000.– Euros of material and a huge melting pot. Just because they measured about 20 feet away from the melting pot and thought they could use a basic IR-thermometer. In reality the mixture was way to much hot. This happened the very first time they used the IR-thermometer..... an expensive mistake.

Like I said before it’s good for an “indication” measurement. By the way this kind of measuring is completely different from “radiation measuring” where you can see the object(s) glow up in a LCD screen. There is sometimes some confusion about the two, because they are both called: Infra Red.

Peter (Stampede)