While touching up the engine around my thermostat on my '73 convertible, I noticed that the spring clips on my distributor were extremely rusty. This needed to be corrected, so I pulled the distributor out of the engine. I removed the spring clips from the distributor, being careful not to break the retaining pins. Both clips have rust over 100% of the surfaces. This was removed by sanding with 400-grit paper. Not all was removed as I could not get down into the coiled crevices. The clips were painted with a dark gray which would look close to original. The clips were put back on the distributor and an attempt was made to drop it into the engine. No success and I noticed that the paint had scraped off. This would not do.
After talking to experts, (Ray, Royce, Tommy Moore, etc.), the clips are supposed to be black. I went to a trade show several years back and one of the samples I took home were samples of Black Magic, which is a room temperature coating for steel. These are somewhere at home, but I could [not] find them. I did find the data sheet which came with the solutions. I called the company's number in Connecticut and got in contact with the local representative. They do not supply small samples like the ones I received anymore due to liability potential. The representative suggested that I obtain a gun bluing kit from a gun shop or Kmart. The chemicals for bluing are almost the same as black oxide coating.
I obtained Permablue from Ben's Gun Shop in Duncanville. A three-ounce bottle was $3.75 and was not in a kit. Kits at Kmart were $8.95 and included a degreaser which I did not need.
First, I washed my clips in thinner to remove oil and grease that might be present on the surface. Since my clips were rusty, I treated them with a 50% hydrochloric acid in water solution to remove the rust which I could not get to by sanding. Rubber gloves should be worn when working with acid.
After that they were washed in clear tap water. I poured a small quantity of the bluing solution in a watch glass. Then I dipped a Q-tip in the solution and swabbed the surfaces with [it]. They immediately turned black. The tech rep said the solution worked better if the solution was warm. This could be achieved by heating the clips in boiling water. I did not warm my clips. (This would've been the next step if the color was not right). I swabbed until I felt the surface was dark enough. The clips were washed in tap water and rinsed with alcohol to displace the water.
The next step was to place the clips in the oven set at 375* F for 30 minutes. This last step was very important. Since I treated the clips with an acid solution, hydrogen gas was produced which also was dissolved in the steel. This baking operation drives off the dissolved hydrogen and prevents hydrogen embrittlement. If this is not done, brittle failure could occur. This failure might not occur right away. It could occur anytime after the clips were put under stress when the distributor cap was installed. After baking I oiled the surface of the clips and installed them on my distributor. This same procedure could be used to treat bolts and other parts which were originally black. This only works on steel.
