Xref: utzoo rec.ham-radio:12371 sci.electronics:7334 Path: utzoo!utgpu!watmath!att!tut.cis.ohio-state.edu!rutgers!rochester!kodak!ornitz From: ornitz@kodak.UUCP (Barry Ornitz) Newsgroups: rec.ham-radio,sci.electronics Subject: Re: Silver Plating, Need Ernie Summary: try electroless silver plating Keywords: silver, plating, electroless Message-ID: <2021@kodak.UUCP> Date: 9 Aug 89 02:11:23 GMT References: <7880075@hpfcdc.HP.COM> Reply-To: ornitz@kodak.UUCP (Barry Ornitz) Followup-To: rec.ham-radio Organization: Eastman Kodak Co, Rochester, NY Lines: 40 Before you read the signature and say: "Ah ha, who better than a Kodak person to talk about silver chemistry" let me add that the chemicals division is (organic) chemicals, plastics, and fibers. That said..... The simplest method of silver plating small parts around the home is to use an electroless silver plating method. The application to tank coils and VHF/UHF cavities is ideal. Electroless silver produces very thin coatings, but these are all that are usually necessary. I have found very little difference between silver-plated coils/cavities compared to shiny copper in respect to efficiency or Q. However, as both surfaces tarnish, the silver plated surface will retain its high Q much longer. Electroless silver will provide just enough silver on the surface of copper or brass to prevent the corrosion of the base metal. Heavy silver plate might be slightly better in electrical performance, but the effort (and cost and complexity) is hardly worth it. One of the easiest electroless silver plating compounds is made by a company called Cool-Amp. This is a powder that when moistened slightly and rubbed on clean copper or brass produces a nice shiny silver coating. Several months ago a pound cost about $70. Don't let the price scare you because a pound will go a long, long way. It will probably last your whole ham club many years if you use it properly. I have made something similar using silver chloride, sodium chloride, and potassium tartrate but the Cool-Amp works better. After buffing the copper surface with steel wool, or even better - a Scothbrite scouring pad, rub the slightly moistened powder on the copper using a paper towel. Make the powder too wet and it doesn't work! You might consider using rubber gloves unless you like having green edges on your fingernails. Finish off the plating with a rinse of clean water. After the object is dry, a coat of clear acryllic spray will help to keep the surface shiny (acryllic plastics also have low dielectric losses). 73 de WA4VZQ, Barry ----------------- | ___ ________ | | | / / | | Dr. Barry L. Ornitz UUCP:..rutgers!rochester!kodak!ornitz | | / / | | Eastman Kodak Company | |< < K O D A K| | Eastman Chemicals Division Research Laboratories | | \ \ | | P. O. Box 1972 | |__\ \________| | Kingsport, TN 37662 615/229-4904 | | -----------------