expired Kester R520A LEAD FREE WATER-SOLUBLE solder paste. SAC305.
Sn 96.5%/Ag 3.0%/Cu 0.5%
Metal: 89.5% Flux: 10.5%
for SMD surface mount solder stencil
Kester R520A is a lead free, organic acid, water soluble solder paste formula specifically designed for use with the higher temperature Pb-Free alternative soldering alloys such as Sn96.5Ag3.0Cu0.5 (SAC Alloys). The solder paste exhibits long stencil life and tack time, while still delivering exceptional solderability to a wide variety of metallic substrates. R520A was formulated to release consistently from the stencil for those critical fine pitch applications (0.5 mm/20 mils) with anti-slump characteristics and preferred solder deposit definition. The activator package in this formula is extremely aggressive, providing superior wetting to OSP coated and Immersion Gold over Electro-less Nickel (ENIG) boards.
Intended for use by hobbyists.
Product is past listed expiration date although for home hobbyists, this should not be an issue.
This item is not for sale to commercial entities. You must be an individual hobbyist who intends to use this for home SMT soldering.
NOTES for use: (These are just hints from my personal experience and should not be taken as gospel.)
From the time you take the paste out and start working with it, it will start to dry out. Dried out paste will begin to clump and is very difficult to work with. My solution is to take a little out, close the container, and use it fairly quickly (within ten minutes). Closing the container when not in use also is important. I use to leave it open for hours while I used the paste and the surface would crust over. Once the paste dries out, adding water never seems to reconstitute it fully. Also in the jar there a white plastic thingy that sits on the flux. You should keep it and put it back every time. It prevents a crust from forming on the paste. If you have any tips to pass along please email them to me and I will consider posting them.
