Morris Wales said:
Reply to Janeau: Hydrogen is created during plating not before and the bath is kept at 130-135 degrees. Pistol parts were allowed to reach bath temp,then plated,rinsed with clear water,dried and baked at 375 degrees for 3 to 4 hrs. 45 years experience. Never had a failure. Morris
Morris, your statement that hydrogen is created during plating it wrong. It is activated during the plating process will be more accurate.
Here is what I found in the published documentation referenced: 1) Hydrogen impregnation occurs only as a result of acid pickling or cleaning of base metal - almost never occur otherwise 2) Chrome plate has the tendency to lock in and seal hydrogen gas in the grain structure of the part; In all cases, it is not until the chrome plate is applied that the formerly inert gases become active.
This is in the plating process that the gases crack the parts. Not after. The gases must go out first.
To complement the info, I made a trip to our local Chrome plater who does Harley parts and show Chrome. They do not bake any parts after plating.
To get another source, I checked with Montreal Chromium who does hard chroming on industrial basis only (unfortunately no guns at this time), and they say the same.
Others research made on the internet ( ''hydrogen embrittlement'' in your search engines) show that for some industrial application, were it is not practical to bake before ( shorter), they bake after (much longer). This is a matter of the type of electroplate used (must be porous), type and hardness of steel. Baking time also vary in regard of steel hardness. For some steel, baking is not necessary.
Some reference ( lot more available) :
http://www.mechanicalplating.com/hydrogen.htm
Hydrogen must be present in the metal substrate before plating. The plating process by itself does not produce the hydrogen.
You were right on the baking after, it can be a process. Thanks for the info.
Which method is the good one? Not very important unless someone does his own plating with a Caswell kit. In that case I will follow their instruction to the letter who state baking BEFORE not after. Their chemicals are used at room temperature.
What is clear, hydrogen embrittlement is something rare and we should not worry about it when chosing a plated finish.
