Neal: I don't know of any OSP coating that can go thru that time/temp 
exposure and still be solderable unless you're using zinc chloride for 
flux :). Seriosly,I wouldn't do it.You may be able to get by with 1-2 hr bake 
at 200-225F depending on the type of OSP coating your using and the 
agressiveness of tour assembly fluxes.					
	We have run testing in the above time/temp ranges on a modified azole	
type OSP with acceptable solderability results.However we use RSA and WSF 
fluxes for flow solder after VP relow.These were stictly informational tests 
and are not done for normal production processing.			
									
				Regards					
				Michael Barmuta				
				Staff Engineer				
				Fluke Corp.				
				Everett Wa.				
				(206)356-6076
On Thu, 20 Jun 1996 16:07:48 -0700 [log in to unmask] wrote:

> From: [log in to unmask]> Date: Thu, 20 Jun 1996 16:07:48 -0700
> Subject: Assembly - OSP? Clarification.
> To: [log in to unmask]
> 
>      Concerning my original question about the possible degradation of OSP 
>      when baking a Thermount or any board prior to wave.
>      
>      1) What's the problem with Thermount, or what could happen if you 
>      don't bake?  Due the the hydrophillic nature of the stuff it 
>      delaminates when not dehydrated...remember measles?...muliply them.
>      
>      2) So, my question is really not about OSPs handling multiple reflows 
>      but OSPs handling a pre-bake prior to the wave.  That's the crux of 
>      the problem.  Can an OSP handle a prebake at say 225 degress F for 6 
>      hours?
>      
>      Thank you for all your responses.  
>      
>      (I do appreciate this meduim, thank you IPC!)  
>