Hi Doug - I have seen a similar problem using "super glues" in very 
     electrically sensitive applications. I was gluing a sensor on a solder 
     squeegee blade and conducting AC Impedance tests but the glue caused 
     wide swings in the measured data depending on how "sloppy" I was with 
     the gluing process. My adhesive guru's said that the cyanoacrylate 
     type adhesives (which many of the super glues fall into) would be a 
     concern in an electrically sensitive application. I changed to another 
     attachment method and the problems went away.
     
     
     Dave Hillman
     Rockwell Collins
     [log in to unmask]
     


______________________________ Reply Separator _________________________________
Subject: Glue and Fine Pitch Devices
Author:  [log in to unmask] at ccmgw1
Date:    8/26/96 9:04 AM


We are currently having our board assembly house use a quick drying glue 
to secure a 30AWG wire to the pcb for a modification.  We are finding 
the glue can cause electrical problems (not all the time) if it is 
in the leads of FINE PITCH surface mount devices.  This is confirmed 
when the glue is removed.  There is the telltale white residue on the 
glue indicating the glue is applied first and the accelerater applied 
second.  Something I've done myself.  It's my understanding that the 
accelerator should applied first and the glue second.  There are no 
controlled impedence issues and comparativley low frequency of 
1 to 32 MHz digital signals.
     
1. Has anyone had electrical problems with glue in the leads of 
   fine pitch devices? 
     
2. Can the glue be conductive for at least fine pitch devices? 
     
I've seen this glue used tons of times without this effect. 
Thanks in advance. 
     
Doug
-- 
     
******************************************************* 
Doug McKean
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------------------------------------------------------- 
The comments and opinions stated herein are mine alone, 
and do not reflect those of my employer. 
------------------------------------------------------- 
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