IR temp gun

[kevmc]

Anyone use a IR temp gun to check mold temp while casting??
What temp did you get?
I picked one up cheap to play with.....going out to try it shortly......

[osteodoc08]

No, But I found my old handheld cheapie left over from my RC days. I plan on playing with it next time I'm casting.

Remember though that it gives a surface temp and not internal temp. Temps can also vary across the surface. It is just a tool in the grand scheme of things and not a be all end all when it comes to accurate temp reading.

[Baja_Traveler]

Havent tried it, but from what I've read here it will give false or bad readings because the surface you are shooting is too reflective...

[Love Life]

What if you spray the outside of the mould with mould release?

[bangerjim]

An IR gun will NOT work on shiny surfaces (lead, al mold, etc). They work just fine on dark surfaces. Remember the "black body radiation" topic from HS physics? There 'ya go! YOUR real world use for something you never thought was important.

IR's are great for furnace/AC register checking, dark surface temps, etc.

You can get a read of your sprue plate temp because it is black. Or maybe a non-aluminum non-shiny mold.

I have several of them and only use them for checking temps of my PC baked boolits in the oven. Not for pot or mold temps.

banger

[dudel]

Not accurate on reflective surfaces. Most only go to about 450F. Molds will get hotter than that when in use.

For this application, a PID or casting thermometer is the way to go.

[Messy bear]

Mine won't work for casting either. Like the guys said too reflective.

[kevmc]

Found out pretty much as stated above......didn't work well at all..........

[blikseme300]

Reflective and wet surfaces cannot be accurately measured using an IR gun. I work in the vegetable business and IR guns fail at giving true temperature readings when the produce is wet.

As with RC engines contact temperature measurement is the only accurate way.

[uscra112]

There's a sticky on the forum here about them. I had to evaluate non-contact temp measurement for an automotive plant application a few years ago, and found them to be virtually useless if any accuracy is required. Surfaces have a characteristic called "emissivity", and it varies all over the map.

[Walter Laich]

I use the laser part to drive the cat crazy.

[Dale in Louisiana]

The key is 'emissivity'. Professional-grade IR/thermography equipment has a way to deal with varying emissivity characteristics of different surfaces.

For instance, machined aluminum, such as one finds on aluminum bullet moulds, has an emissivity of 0.07 while dull brass is 0.22 and oxidized (blued) steel is 0.80. If you point an IR thermometer at each of those, even though they are actually at the same temperature, you'll get wildly different readings from them. Aluminum and brass will show very much lower than actual temperature because they radiate less energy.

If I'm shooting outdoor overhead aluminum buswork in a substation, I have to make sure that I enter the proper emissivity number otherwise my readings will be invalid. Thermographers know this.

However, If you use your cheapo IR thermometer on your aluminum mould and find that it casts good boolits when you are reading, say, 180 degrees, even if that isn't the actual temperature, the next ime you cast, you can heat that mould up to that same 180 degrees as read on your thermometer, and it will be at the same temperature. The readings will be repeatable. Wrong, yes, but repeatably wrong.

dale in Louisiana
(IR surveys since 1990 - among other things)

[newmexicocrawler]

I have tried my ir gun against my thermometer and the readings are worlds apart....ir reads service temperature.

[detox]

I use IR whenever i heat up my RCBS moulds. Temp may not be exact, but it is repeatable. I heat up mold with propane torch to 200 degrees then start casting, mould will get hotter 285-300 during casting.... according to cheap RadioShack IR gun.

The IR will not work on shiney aluminum moulds because of reflective finish. You have smoke the bottom or end of mould and get temp from this blackened area.

[gtgeorge]

I have used mine but as others have said it is not accurate. It will however work okay if you base your readings on known spots and angles and readings from previous sessions. Not worth the trouble. A PID controlled hotplate works so much better.