Non heat treat cad plating
Are there any cad plating processes out there which do not require heat treatment of high tensile components? If so please let me know where to find information on them. We have a small aircraft restoration shop and are interested in doing the process ourselves.
Thank you,Robert O Powell
Lead Structural Mechanic (Aviation) - Calhoun, Georgia, USA
Cad plating is not a casual undertaking. Being a cumulative toxin, it requires medical monitoring in addition to all of the usual regulatory-intensive safety and environmental considerations involved in electroplating. There is a process called ti-cad that may assist with your needs. The plating bath is cadmium, but insoluble titanium dust is co-deposited with it which keeps the deposit from being continuous and allows the substrate to "breathe" to reduce hydrogen embrittlement.
Hydrogen embrittlement relief is done at about 375 degrees F (not over 400 deg. F), and I don't know if it is really appropriate to call this "heat treatment" although heating is obviously involved. Further, hydrogen embrittlement can occur during pretreatment, not just the plating step per se. I would ask you to use multiple sources to investigate your needs, not to rely just on responses in this public forum, because it is very easy to misunderstand the questions or the answers.
Ted Mooney, P.E.
Pine Beach, New Jersey
Striving to live "Aloha"
There is also a selective plating process intended for restricted areas and low volume applications that has a specially developed solution known as No-bake Cad or Low Hydrogen Embrittlement Cad (LHE Cad). It's chemistry is based on an organic solvent, not water. It has to be used with extreme care to avoid water or humidity from entering the plating area and by personnel certified in aircraft repairs. Brooktronics Engineering Corp can give you more details.Guillermo Marrufo
Monterrey, NL, Mexico
Robert, there is also vacuum cadmium plating available. I believe ionEdge offers equipment to deposit cadmium in this manner. Vacuum cadmium coating does not require post plate baking.
Intank LHE cadmium plating ,the solution should be tested at least weekly, and before releasing the parts. I have seen one company in canada which used to do electroless nickel on high strength steels, if you can get the approval you can try it , it's somewhat easier.
- Al Ain, UAE
October 5, 2010
An aerospace subcontractor has a requirement to cadmium plate per QQ-P-416 [link by ed. to spec at Defense Logistics Agency, dla.mil] . They elected to brush plate (Mil-STD-865 [link by ed. to spec at TechStreet]) using a "no-bake" formulation. What is the opinion in substituting brush for (immersion) electroplate...relevant to QQ-P-416 certification? For substituting "no-bake" formulation for acid cadmium and eliminating HE-relief bake?Doug Hahn
- Saint Charles, Missouri
October 7, 2010
Before carrying out any operation that differs from the drawing requirements you need to get permission from the customer to deviate from the drawing. Don't do anything until you get this permission, otherwise you may open yourself up to all sorts of problems.
Saying that, dependent on the geometry of the part and the area to be plated you may well be able to use a no-bake brush cadmium plating. The solution will need to be certified as tested against and complying to ASTM F519-17A [link by ed. to spec at TechStreet] , or if it not certified you will have to get it tested against this specification before you consider using it. Each separate batch number of the no-bake solution needs to be tested and certified against this specification to ensure the solution is truly a no-bake solution.
aerospace - Yeovil, Somerset, United Kingdom
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