Metal finishing Q&As since 1989

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Abrasive blasting prior to EN plating

Slightly confused on the reasoning behind the glass bead blast recommended by our plater. The parts are bobbin assemblies, made of two silicon iron flanges brazed to a 304L stainless steel shunt. The assemblies require Electroless Nickel plating at .0005" thickness. The bead blast is required for good adhesion to the substrates, according to the plater. Is the bead blast required for silicon iron, or stainless steel, or both? We must get away from glass bead blasting these parts due to the difficulty in cleaning the beads off the parts, as well as the beads embedding into the material. I'm looking into a replacement blast media such as a coarse grain soda blast? Please share any thoughts or suggestions on this application. The parts are currently bead blasted in a rotating basket.
Thanks.

Larry Peters
Engineering - Wallingford
2005

My 2 cents goes with a bead blast is NOT required if you have proper preplate steps for a given material. Now if you have heavy welding oxidation or flux, a bead blast would certainly be helpful.

James Watts
- Navarre, Florida
2005

You had already posted this problem. Some authors suggest the bead blasting as an alternative when there are different substrates assembled together that would otherwise require different treatments. Stainless steel requires a highly acidic Wood's strike which in turn may be detrimental to the silicon iron due to the galvanic couple and venom if there are gaps between both that may entrap some of it. Isn't it possible to plate them separately and assemble afterwards?

Guillermo Marrufo
Monterrey, NL, Mexico
2005