I've always found that the Thernolabel temperture strips work well for
determining the maximum temperature reached during a thermal process. They
are inexpensive and easy to use.

These strips come packaged as individual strips on a release paper. You
simply remove the strip from the paper and the adhesive on the back of the
strip will stick to your substrate. There is a temperature range for each
strip, usually 50 deg F in 10 deg increments (i. e. five individual zones).
You simply read the last zone that turns black as the maximum temperature
obtained. Therefore, you know the temperature that your board reached within
10 deg F. Different temperature strip sets are available covering the
temperature range from 90 deg F to 500 deg F

The theory of operation of these strips is interesting. Basically, the
manufacturer looks in his Chemical Rubber handbook and looks for a white,
crystaline organic compound with the melting point that he is looking for
(for example 140 deg F). He takes this compound and grinds it up with his
morter and pestle. He then takes this finely ground powder and coats carbon
black balls (which now look white) and places this mixture on the specific
zone of the temperature strip (in this case the 140 deg F zone). When the
strip is placed on the board and the board reaches 140 deg F, the organic
compound will melt off the carbon black balls and this zone will now look
black. I'm sure it is a little more involved than this, but this is the
general principle. I would bet that the guy (or lady) who figured this out is
quite wealthy by now.

These strips are available from most laboratory supply houses (such as Fisher
Scientific, Sargent Welch, Cole-Parmer, etc.) however, I usually obtain them
from:

Paper Thermometer Company
P. O. Box 129
Greenfield, NH 03047
Phone: (603)-547-2-73

Hope this helps.

Larry Fisher
Dexter Electronic Materials
[log in to unmask]

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
##############################################################