Electronics Forum | Tue Nov 05 22:57:50 EST 2002 | davef
Grainy solder is a process indicator. It is not necessarily a defect. Search fine SMTnet Archives for background.
Electronics Forum | Fri Jun 25 15:48:55 EDT 2004 | tcp
The potting definitely is a factor in fracturing the grainy joints, but does not seem to damage a "good" solder joint.
Technical Library | 2007-08-16 13:34:31.0
While experienced inspectors may be able to determine the aesthetic differences between a lead-free PCB assembly and a tin-lead version, one cannot rely on the "experienced eye". "Less wetting out to the pad edges" (Figure A) and "graininess and lack of shininess of the solder joint" (Figure B) are typical comments about some lead-free solder joints. However, in cases where a Nitrogen atmosphere was present during the reflow of the solder joint (Figure C), there will be little visual differences between the lead free alloys and their tin-lead counterparts.
| http://etasmt.com/cc?ID=te_news_bulletin,23576&url=_print
. Dull or grainy joints are not a big concern – the grain structure will grow in a joint over time anyway. But having a dull joint is giving this eventuality a “ head start
Blackfox Training Institute, LLC | https://www.blackfox.com/blackfox-to-lead-free-or-not-to-lead-free-that-is-the-question/
. One of the disadvantages of lead free solder is that it is rough and grainy compared to leaded solder. Lead free solder also generally requires tighter temperature regulation on the soldering iron
