Difficult to say. Firstly, what kind of IC? I suggest à priori that the
product may be a heavy polyglycol, without being categorical. Some ICs,
especially epoxy DILs and possibly SOICs, were tinned using activated
polyglycol-based fluxes and they were notorious for the flux penetrating
under a poorly adherent epoxy/lead "joint". I have seen ICs with 0.2-0.3
mm gaps between the lead and the epoxy, ideal capillaries for flux
residues. Note that I'm not saying that this is the cause in
Jean-François' case, but it does spring to mind.
Brian
On 15/03/2011 16:48, Jack Crawford wrote:
> As Jean-Francois notes, his company policy doesn't permit him to subscribe to technet. If anyone has any suggestions or ideas, please also send your comments to him when you reply to TechNet.
>
> Thanks
> Jack Crawford
> IPC
>
> From: Jean-Francois Bissonnette [mailto:[log in to unmask]]
> Sent: Tuesday, March 15, 2011 9:36 AM
> To: Jack Crawford
> Subject: Cannot go on technet... but I have a question.
>
> Hello M. Crawford,
>
> I once was a member of IPC. Since I changed company, I do not have thesame liberty and right now I find myself with a problem that I never hadbefore.
>
> After assembling a IC with Water Soluble flux and washing the board in hot water, I find some kind of greasy residue... looks like syrup a little bit. It does not seem to dry over a few days. I have no clue and likeI said, I don't have access to Technet at the moment. (cie policy).
>
> Important ICs are hand soldered and hand washed with a brush under the hottest water possible. They are dried with compressed air. The residuedoes not show up anywhere else than around the IC.
>
> Would you have any idea on what it is and/or how to confirm what it is?
>
> Thanks a million!
>
> Jean-Fran�ois Bissonnette
> DEPRO �lectronique Inc
> 755, Cur�-Boivin suite 101
> Boisbriand, Qu�bec
> Canada J7G 2J2
> Ph. 450.430.6251 Poste/Ext: 109
> Fax: 450.430.6251
>
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