IR vs. direct contact thermometer

By CWI555

Date 05-05-2009 00:15

There are some lengthy discussions already on the forum. I would suggest using the search function.

By darren

Date 05-05-2009 02:33

whichever you use, a handy assortment of temp sticks always is a nice backup. shows you heat transition zones better than an ir gun.
also when you double check with the temp sticks it gives you a real time calibration report of your thermometer even though it isnt official.
darren

By SWP

Date 05-05-2009 13:35

One very important fact you need to know about all IR thermometers is that the surface finish of the object being measured can drastically affect the reading. If you have a flat black surface, and a shiny chrome finish, both the same temperature, the black surface will read much higher than the shiny one, this is due to the emissivity of the surface. Good quality IR sensors have adjustable emissivity and thus you calibrate the sensor to the type of surface you are looking at.

By G.S.Crisi (****)

Date 05-05-2009 16:04 Edited 05-05-2009 16:08

What does IR mean? Here in Brazil means Imposto de Renda (income taxes)
Giovanni S. Crisi
Sao Paulo - Brazil

By welderbrent (*****)

Date 05-05-2009 16:07

Infra-Red. Many have a 'laser' light so you can accurately point it where you want to read the temperature. Reads in degrees C or F.

Could take our temps when we pay our taxes. That's when I see red.

Have a Great Day, Brent

By SWP

Date 05-05-2009 20:34

By the way, excellent article on IR sensor use in current spring issue of AWS Inspection Trends Magazine, which you can access from the home page.

By scrappywelds (***)

Date 05-06-2009 01:37

I personally like the infra-red on high heat applications (no possible accidental burns) but for inspection the old temp stick leaves that mark. I actually hade a boiler inspector once tell me to cut out a weld repair I made because I used an infra-red instead of the temp sticks supplyed for the pre-heat. When I tried to state my case he simply said prove it was up to temp, no mark no proof. You can guess the rest of the story. Also temp sticks don't need batteries.

By welderbrent (*****)

Date 05-06-2009 14:33

They also do not require calibration other than the manufacture's ratings on product quality.

Good points when considering temp control.

As an inspector, what I like about the IR is being able to check someone as I am just walking past and knowing with a quick glance at the digital readout that they have the item in question in the heat range it should be and they didn't even know I was there or watching. Works good on many structural that are not 'HIGH' critical for pre-heat and interpass temps. And doubly if the job is in a difficult position to get to and the welders may think you are not checking them because of the difficulty of getting to where they are at.

An IR doesn't have to read dead on to let me know they have pre-heated the part and are somewhere between minimum and, if applicable, maximum temps.

Have a Great Day, Brent