Lou,

Solder float (for PWBs solderability; surface pads and PTHs) is done in a solder
pot at 245C +/- 5C for 5 seconds maximum (and as normally you don't want to 
fail, you test as close to 5 seconds as you can).  See section 4.2.3 of 
ANSI/J-STD-003 (available from IPC).  These parameters are unchanged from 
IPC-S-804A (which was superceded by ANSI/J-STD-003).  

Note that this test is designed to evaluate the solderability of the specimen 
and isn't really a "worse case" thermal shock test for PTH durability.  If you 
are interested in the PTH durability, I would recommend the following (taken 
from MIL-STD-55110D).

     3.9.2  Rework simulation, plated-through holes.  Types 2 and 3 
     printed-wiring boards shall be inspected in accordance with 4.8.6.2.  After 
     the fifth cycle of soldering and unsoldering of the test wire , the 
     plated-through hole shall exhibit no plating cracks, blistering, or 
     delamination in excess of that allowed in 3.5.3.  Laminate voids in zone B 
     (see figure 8) with the longest dimension of 0.003 inch (0.08 mm) or less 
     shall be permitted provided all minimum dielectric requirements are met.  
     Resin recession at the outer surface of the plated-through hole barrel 
     shall be permitted and is not cause for rejection.
     
     4.8.6.2  Rework simulation, plated-through hole (see 3.9.2).  Rework 
     simulation of plated-through holes shall be in accordance with IPC-TM-650, 
     method 2.4.36.  Following the fifth cycle of soldering and unsoldering of 
     the test wire, the plated-through holes shall be microsectioned and 
     inspected in accordance with 4.8.1.2 and mneet the requirements of 3.9.2.  
     The rework simulation shall be performed after stabilizing of the coupons 
     at temperatures of 59øF to 95øF (15øC to 35øC) and relative humidity of 40 
     to 85 percent for a period of 24 hours.
     
Hope this helps

Jim Maguire
Principal Engineer, E/E M&P
(206)657-9063
Boeing Defense & Space Group
[log in to unmask]
______________________________ Reply Separator _________________________________
Subject: Solder Float/Shock Testing
Author:  [log in to unmask] at esdigate
Date:    8/22/95 11:38 AM


Hello all:

We would like some information on temperature and time required prior to 
testing a sample in the solder pot for solder float/shock testing.

We checked in the IPC Test Methods but could not find the specific 
information that we were looking for.  Any help would be greatly appreciated!

Sincerely,

Lou Cerone, Process Engineer
Benny George, Quality Control Tech