[TriEmbed] need stupid pet trick immediately

[Van Watts]

Hi there,

If you don't have any objection to it, a very small amount of cyanoacrylate glue applied to either the thermocouple junction (tip) itself or the insulator just next to the junction should work.  I believe that's how we have done it in the past. I think it can be removed by softening it up with a heat gun and/or chipping it off.

I don't recall how expensive thermocouples are since I haven't had to buy them myself, so I don't know what the cost of potential damage is. In any event, I believe we have reused them--especially if the glue is applied to the insulator.

Regards,
Van

Sent from my iPhone

On Oct 15, 2014, at 5:24 PM, "Dwight Morgan" <dwight.w.morgan at gmail.com> wrote:

You might try a tiny metal C-clamp with Teflon under the contact areas. I
think Teflon tape folded a few times would work if you don't have small
pieces. 

Dwight

-----Original Message-----
From: TriEmbed [mailto:triembed-bounces at triembed.org] On Behalf Of Pete
Soper
Sent: Wednesday, October 15, 2014 3:44 PM
To: Triangle Embedded Computing Discussion
Subject: [TriEmbed] need stupid pet trick immediately

I've got four of the typical high temp fabric-coated type K thermocouple
probes and can't get the buggers to reliably sit with some tension on the
top of PCBs in an oven. I can imagine many solutions better than the
fractional hectares of Kapton tape I'm applying along with bending the
freaking things down, then pulling them back up with the silly hope that
they'll sit on the target board surface.  The kapton is of course screwing
my experiment 'cause it is a fabulous heat insulator.

What is the proper way to do this??? The crux of the problem is "something"
that can magically hold the last inch or so of thermocouple lead down
against the PCB where the lead kisses the PCB and the thing holding it down
doesn't itself hose up the temperature measurement process.

This is what the oven drawer looks like. As you can see, the thermocouple
lead is threaded through the slots in the drawer, and with a bit of tape
that keeps it from being sensitive to the drawerin being slid back and
forth. It's that last bit of getting the thing to reliably sit on the PCB
and not pop off and start measuring air temperature that's killing me. Any
help appreciated.


http://triembed.org/blog/wp-content/uploads/2014/10/2014-10-05-T962-Actual-W
ith-Text.jpg


-Pete


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