laser temperature gun

[Cooperman]

Can you get an accurate temp reading of you lead temperature with one of these, or is a probed device better?

[Hossfly]

Probed better, laser depends on color, shiny surfaces not accurate. Frying fish good though.

[Scrounge]

What he said. My former employer spent hundreds of dollars on high-end laser temp guns, for that very reason. For the things most of us do with one, a cheap one from Harbor Freight, or similar, will do fine, but not for measuring molten metal or any other shiny surface.

Bill

[Soundguy]

Can you get an accurate temp reading of you lead temperature with one of these, or is a probed device better?

With in-lead thermometers so cheap.. that's what I opted for. A nice RCBS

[TjB101]

My pot o’ lead running at 710 degrees was showing 450 shooting the surface of the lead. Not good for casting. It was showing an accurate number hitting the side of my mold.

[Nueces]

I haven't tried it, but I understand one can read temperature of molten lead by scanning a floating piece of iron.

[abunaitoo]

They work, but to me, are not consistent.

[kevin c]

K probe digital readout on a PID controller is the way I go.

I couldn't get agreement of the IR gun with the in-the-pot RCBS type dial thermometer, and neither were able to regulate the temp in any case.

[bangerjim]

IR thermometers work on the "black body radiation" principal and do NOT work well on any shiny surface at all.

You can obtain a black oxide-finished large washer, float it on the surface and read off of that. It will be pretty accurate! And yes, steel floats on lead. That is how I check my pot temp against a K t-couple.

[No_1]

I float a small washer on my melt and measure the temperature of the washer the the temp gun.

[Brokenbear]

You don't say what kind of pot but I get a pretty accurate reading shooting the rod of my bottom pour pot when I target the beam on the rod to the pour valve just above the lead level

Bear

[Mike W1]

IR thermometers work on the "black body radiation" principal and do NOT work well on any shiny surface at all.

You can obtain a black oxide-finished large washer, float it on the surface and read off of that. It will be pretty accurate! And yes, steel floats on lead. That is how I check my pot temp against a K t-couple.

I'm off topic with this but couldn't insert a picture of this on a PM. This TC came with my VOM and am wondering just what it'd be useful for. Kind was thinking of using it to monitor the temperature of a SSR for the sake of curiosity. Any suggestions?
Thanks
ATTACH=CONFIG]290982[/ATTACH]

[uscra112]

BTW the laser is just an aiming aid. It has nothing to do with sensing the temperature.

Some years ago I did an extensive engineering evaluation of non-contact temperature sensing for an automotive process control application. Gave up. The technology is far too dependent on the surface characteristics of the target. It can be calibrated to a particular surface, such as the web in a papermaking system, but their ain't no such animal as an accurate generic sensor, and CERTAINLY not one that retails for $30.

[bangerjim]

I'm off topic with this but couldn't insert a picture of this on a PM. This TC came with my VOM and am wondering just what it'd be useful for. Kind was thinking of using it to monitor the temperature of a SSR for the sake of curiosity. Any suggestions?
Thanks
ATTACH=CONFIG]290982[/ATTACH]

Well, first..... the hot Pb will meld that blue insulation.

You will only get a temp measurement at the very surface. You really do not want to insert the insulated part in the melt.

Buy a metal rod K style t/c long enough to go into your pot. The wires stay out. and use that with your meter. I have several of those things you show that came with test meters and the are garbage.

[Mike W1]

Well, first..... the hot Pb will meld that blue insulation.

You will only get a temp measurement at the very surface. You really do not want to insert the insulated part in the melt.

Buy a metal rod K style t/c long enough to go into your pot. The wires stay out. and use that with your meter. I have several of those things you show that came with test meters and the are garbage.

Obviously I didn't word things right so It'd come across as what I meant. Will try to do a little better this time.

1. What probably was that little bead intended to be used for? Must have some purpose.

2. I have an assortment of probe TC's that I do use for insertion into a pot of molten lead.

3 I just want to monitor the temperature of the SSR while casting. I "think" that temperature is warm and not hot.

4. Will taping that bead to the SSR give me at least a "ballpark" figure?

5. Or is there some other type TC that would work better to monitor the temperature of the SSR?

6. Maybe I'm just bored as I have 2 pots, a hotplate and a luber heater all hooked to PID's. Also a PID that I intentionally omitted installing a heat sink in. Just wanted to see the comparison when in use with and without a heat sink.

[bangerjim]

Obviously I didn't word things right so It'd come across as what I meant. Will try to do a little better this time.

1. What probably was that little bead intended to be used for? Must have some purpose.

2. I have an assortment of probe TC's that I do use for insertion into a pot of molten lead.

3 I just want to monitor the temperature of the SSR while casting. I "think" that temperature is warm and not hot.

4. Will taping that bead to the SSR give me at least a "ballpark" figure?

5. Or is there some other type TC that would work better to monitor the temperature of the SSR?

6. Maybe I'm just bored as I have 2 pots, a hotplate and a luber heater all hooked to PID's. Also a PID that I intentionally omitted installing a heat sink in. Just wanted to see the comparison when in use with and without a heat sink.

The "bead" IS the t/c! A T/c is simply a specially welded junction of two dis-similar isothermic metals, in this a type K. (Nickel-Chromium / Nickel-Alumel). That little "bead" is in the tip of every t/c made. Then encased in ceramic powder and inserted and sealed in a SST metal sheath for protection.

You can put it in "intimate" contact with the SSR/heat sink to monitor the temp, but I really don't understand why. That has no reflection on the casting pot temp. The SSR heat sink "should be" totally isolated from the line and will not cause any problems with your meter.Tape it to the heat sink using duct tape or high-temp furnace tape if you have it.

[Mike W1]

Why??? Just cause I want know I guess. I'm certainly not current on electronics since 65-68 in that line in the ASA and 36+ in telephone. But know the principle of the TC and that a SSR is basically a switch turned on/off by a signal from the PID. Beyond my need to know or understanding the innards of the PID.

Must be some reason for a bare tipped TC or they wouldn't make em'.

[uscra112]

Why shouldn't he be interested in the temperature of the SSR? Independent of pot temperature? They do tend to run hot, y'know.

That bare tip thermocouple that comes with some meters in intended for exactly that purpose. Measuring component temperatures. Heat is, after all, a component killer.

[Cast10]

Probe in pot/PID.

Temp gun for checking heat of PC bullets after cooking, general heat along edge of pot, heat of single burner for mold preheating, temp of mold on burner; good to have one around.

[bangerjim]

Why??? Just cause I want know I guess. I'm certainly not current on electronics since 65-68 in that line in the ASA and 36+ in telephone. But know the principle of the TC and that a SSR is basically a switch turned on/off by a signal from the PID. Beyond my need to know or understanding the innards of the PID.

Must be some reason for a bare tipped TC or they wouldn't make em'.

2 reasons:

1> CHEEEEEP! Very CHEEEEEP.

2> A bare tip responds almost instantly to temp changes, where a rod style takes longer to heat the sst outside and the ceramic powder surrounding the t/c junction inside. Most industrial apps do not need instant response since heating and cooling processes have significant lag times involved. If they do need instant response, most use either thin-film t/c's or thin-film 100 or 1K ohm RTD's pasted right on the surface of the device or vessel they are monitoring. (I do this stuff for l living in the engineering firm I own, by the way!)

[Mike W1]

I knew you had the background for this stuff and was hoping you'd reply. I appreciate your posts.

[Mal Paso]

Obviously I didn't word things right so It'd come across as what I meant. Will try to do a little better this time.

1. What probably was that little bead intended to be used for? Must have some purpose.

2. I have an assortment of probe TC's that I do use for insertion into a pot of molten lead.

3 I just want to monitor the temperature of the SSR while casting. I "think" that temperature is warm and not hot.

4. Will taping that bead to the SSR give me at least a "ballpark" figure?

5. Or is there some other type TC that would work better to monitor the temperature of the SSR?

6. Maybe I'm just bored as I have 2 pots, a hotplate and a luber heater all hooked to PID's. Also a PID that I intentionally omitted installing a heat sink in. Just wanted to see the comparison when in use with and without a heat sink.

SSRs generate about 1 Watt of heat for every Amp controlled, only when it's on. Typically about 7 watts, like an old fashioned night light.

I use the thermocouple to set the temperature on my dry mount press. I can put it anywhere under the 18x23 platen. The old way was one shot thermal strips. They may be cheap but they are useful.