Infrared/laser thermometer for molds

[HDS]

I was looking up on this concept and it seems very interesting. Now I read there are difficulties because of the molds surfaces and reflectivity. But what if you marked off an area on the side of the mold and sprayed it with a matte black high temp paint? You could put that on all your molds and measure them in that spot to see what the temp is.

Does this sound like a workable solution, I would dearly love to have some way to see what temps my molds are running at a glance. The method with a probe temp was too clumsy for my tastes and I only wanna know occasionally.

I think I will repurpose the probe temp I got for that purpose into a mold oven instead.

[BoolitSchuuter]

Yes, that will work very well. Also if you were to paint a disk of thin sheet metal, you can float that on the surface of your melt and get the surface temp. Use flat black hi-temp paint.

[Jim]

I thought about doin' that one time. Then it occured to me, if the boolits are comin' out right, what does it matter?

I guess I'm lookin' at it as I do the necessity to know velocity. As long as the accuracy suits me, it don't matter what the velocity is.

[HDS]

Well bullets aren't always coming out right for me, usually too low temp. Once I get them hot enough it starts working properly, I'd like to know what temps they are running at when they work properly and I would like to know how the temperature changes between pours, how fast I need to go to keep the temps up and what is too slow.

I also want to know how high does my hotplate heat the molds at setting #4, setting #3 is good enough it seems to bring it near operating temperature but seldom up to it, setting #4 can take it right past and give me lead that won't solidify in the mold. A temperature gague could tell me if it's possible to reach the proper temp on #3 with enough time, and if setting #4 is risking damage to my moulds.

Got my Mihec 9mm 6-cavity too hot once, lead didn't solidify and splashed around, got loads of lead smears and some damage to the molds top face near the hinge from lead I didn't know was there until too late. It's now been taken apart and cleaned up a bit.

As you can see I have some notion of what works and what doesn't, but I desire to know the actual temperatures and they could help me answer some questions I have as well as give me a better idea on how to gague stuff in the future by feel.

[theperfessor]

There have been a number of threads on this subject. The general consensus is that the IR sensors aren't very accurate at reading most metal surfaces, although flat/matte black surfaces are better. They need to be calibrated to give an accurate reading. They can be off anywhere from a few degrees to a few hundred degrees. I have one and I can agree with that conclusion. That doesn't mean they aren't useful. Let's say you're casting and you hit a particular alloy/mold temperature where the bullets fill out great and pop out of the mold when you open it. An IR sensor can give some temperature values that you can record and then use the next time.

They may be inaccurate in an absolute sense, but they are pretty consistently inaccurate in a relative sense, if that makes any sense.

[Catshooter]

I have an IR laser made by Fluke. It works very well on my Lyman (iron) moulds. It hates the surface of the molten lead in the pot.


Cat

[theperfessor]

Hey Cat, I'm betting your Fluke is a better unit than your typical HF offering. I like having a thermocouple/PID on my molds, don't need an extra hand to use it and I get a continuous temperature readout.

I like my cheap HF IR temperature gauge for some things, such as using it to find air leaks in the house in the winter.

[cajun shooter]

You have many variables that will create a problem when trying to have a hotplate repeat the exact setting each and every time it's used. I think at best you will have a spread to deal with.
I always have a hotplate on my casting bench for my moulds, not for just preheating but also to maintain my mould temperature through the entire bullet run.
The problem is the thermostat that is used in the ones for sale at Walley World and other stores. They are cheap and made in China for the most part.
I have a standard alloy thermometer that I use for my alloys that also works well when put on the plate of my large GE single burner hot plate. Try it, it works well

[Wal']

I like my cheap HF IR temperature gauge for some things, such as using it to find air leaks in the house in the winter.

Now thats one I havent thought of "theperfessor", finding the drafts around the house, & I live in the snow 4 months of the year, unusual for most Australians. [smilie=b:

Gonna try it right now, thanks, great idea. :smile:



Edit, yep it work's

[John Boy]

Does this sound like a workable solution, I would dearly love to have some way to see what temps my molds are running at a glance. Naw! Change to a different alloy for the same bullet and you'll have a different temperature when the mold casts - just right.

The alternative is ... the number of seconds it takes for the sprue puddle to frost for perfect bullets! And there is no extra tool needed to determine it!;)

[theperfessor]

Wal' -

Great, maybe help you save a little money on energy.

[Catshooter]

Keith,

I would imagine the Fluke is better than a Harbor Frieght themometer. It works very well.

I too have used it to find cold air leaks. Seemed kinda cold one day in the hallway where the washer/dryer were located. The Fluke showed me that it was five degrees below zero behind the dryer, in the house. Fixed that problem right quick. :)


Cat

[Wal']

Wal' -

Great, maybe help you save a little money on energy.


Like I said, live in a ski resort, sat there last night beaming around the lounge finding all the cool spots & drafts.

Next summer know where more insulation will be going.

Thanks again for that idea, Wal' :castmine:

[EDG]

I have one of the Harbor Freight IR thermometers. It has it's quirks but about 30 to 45 minutes into my first casting session I figured out how to make it work. On a Lee mold it will read the temp of the sprue plate easily. It does not work well pointed directly into freshly fluxed clean bright metal in the pot. Once a layer of crud piles up it can be pushed to one side and the temp can be measured on the surface of the non-reflective dross. Barring that I found that I could get a good reading when pointing right at the intersection of the molten metal and the pot wall. It may take 2 or 3 tries but there is usually a dark ring of crud right at the pot wall you can point the laser at.

[HDS]

You have many variables that will create a problem when trying to have a hotplate repeat the exact setting each and every time it's used. I think at best you will have a spread to deal with.
I always have a hotplate on my casting bench for my moulds, not for just preheating but also to maintain my mould temperature through the entire bullet run.
The problem is the thermostat that is used in the ones for sale at Walley World and other stores. They are cheap and made in China for the most part.
I have a standard alloy thermometer that I use for my alloys that also works well when put on the plate of my large GE single burner hot plate. Try it, it works well

Yes the way I cast I have the hotplate as the resting place for my molds. Setting 3 is too cold though and I am afraid setting 4# might be too high if left too long.

http://farm9.staticflickr.com/8281/7616488332_ac3a32a1b4.jpg (http://www.flickr.com/photos/82846378@N07/7616488332/)

http://farm8.staticflickr.com/7257/7616492338_b73b50c68f.jpg (http://www.flickr.com/photos/82846378@N07/7616492338/)

One of my future projects is to make a mold oven, essentially a big box of aluminum with a thermometer in it, that way I could have a good idea of what the temps the molds are.

My old phone just died though so its off to look for a new one, there went my infrared budget. Something for next year then.

[HARRYMPOPE]

Naw! Change to a different alloy for the same bullet and you'll have a different temperature when the mold casts - just right.

The alternative is ... the number of seconds it takes for the sprue puddle to frost for perfect bullets! And there is no extra tool needed to determine it!;)

I agree and its my way as well.

George

[Bigslug]

I too have recently acquired the Harbor Freight model, and seem to be experiencing the reflectivity issues being discussed.

I stuck my new aluminum NOE mold in the oven to cycle the temperature from room to operating a couple of times to help seat the alignment pins per instructions.

The thermometer reads the pizza stone in the oven to within a few degrees of what the oven claims to be set for, and it reads human body temperature when I zap myself in the head with it, but it WOULD NOT give an accurate read off either the shiny aluminum mold or the black steel sprue plate. Even after sitting on a 400 degree pizza stone in a 400 degree oven for half an hour, the mold and sprue plate were reading 150 or less - which is clearly not the case.

Gonna have to try it on an iron mold body. Looks like no joy for this one.

[machanic]

Just cast my first few boolits, several attempts before I got good results, I was using a HF infrared temp unit, best results with the mold temp indicating 150 deg F. and the lead (wheel weights) at 350 deg F. Coincidence on the 150 deg.F mold temp??

[ClassicCannons]

Hi
What i used when i was in the service for welding was heat indicating markers. They work well but won't work on melted lead ? but if you mark the side of the mold and then when it changes color your ready a links is below their kind of costly between 11-16 bucks but i'm sure theirs some cheaper out their thanks AMG
http://www.airgas.com/CachedImages/0000004/t047_r06994_v-2.jpg

http://www.airgas.com/browse/product_list.aspx?catID=381&WT.svl=381

[uscra112]

Reflectivity has nothing to do with it. The parameter that governs how well or badly a IR measuring tool works is emissivity.

BTW the laser has nothing to do with the measurement - it's just an aiming aid. The device measures by quantifying the radiation that's hitting an infrared-sensitive photocell. Said photocells are also a source of error - they drift, they are affected by their own temperature, the lens in front of them can get dirty, and-and-and.