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View Full Version : Rough test of TC's and Laser IR measurements



Mike W1
04-21-2015, 02:51 PM
Had a little idle time today so spent it doing some informal testing on gear. Anyhow here's the results.

EQUIPMENT USED:
PID Auber SYL-2352
P1 - Auber WK-191 TC Diameter .1181"
P2 - ebay TC diameter .1994"
P3 - ebay TC diameter .1191"
P4 - ebay surface read TC
IR - Harbor Freight Laser IR thermometer
Craftsmen Volt/Ohm Meter

Note: K type thermocouples are noted for not being
real accurate in the range we use. 2° to 4° being what
one might expect for error.

TC probe P1 is the one in the pot signaling the
PID unit and has been offset with the Ice and
boiling water method.

P3 is the probe I insert into the mould to read
mould block temperature.
Mould temperature
P3 IR P4
210° 146° 168°
219° 190° 190°
224° 147° N/A

Compared readings of P2 and P3 to get an idea
of differences. PID was set at 715° and didn't vary
more than ± 2°
P2 P3
711° 688°

Placing P2 into the melt with tip about 1" in or near
bottom of pot roughly indicates the surface "might"
be 1° to 2° hotter than towards bottom.

Placed large rust covered washer on melt surface to
try Laser thermometer. When pot was stabilized at
715° setting and P2 read in the 711-712° range the
IR aimed at the washer bounced around anywhere
from 300° to about 500°. Never did get a reading
that was anywhere close to a reading on either side
of it. Held the IR 6-8" away from the washer, maybe
I should have been farther away than that? I don't find
my unit to be of ANY value for casting lead!2-4°

Auber's Q&A section says something about thinner
TC stems responding faster to temperature changes
and that seemed to be the case between P2 & P3.

RED333
04-29-2015, 08:38 PM
I work in the cooking gear repair field, when a customer brings out one of those IR things
I just laugh. Customer asks what is so funny, point the IR at a shinny wall and shine a light
at the wall and watch what temps you get. IR is subject to reflectivity, IR compares the diff
in temps of a surface. If you get a "shinny" spot next to a dull spot the temp will show up
as hot and it is not as hot or cold as it truly is.