Thursday, December 21, 2006

Polishing the Bell, part 2

After the bell has been sanded, filed, dents hammered out, and so forth, it is time to get it on the buffer. I use a high speed buffer, with blue tripoli. (The company calls it "polish compound" It is tripoli. I know because it only took three hours to get it looking like the top picture instead of the nine hours if I used rouge alone!) Rouge is usually made of iron oxide, and is therefore red in colour. Other compounds are now getting common, titanium dioxide for instance is much in my favor because I can polish scratches out of the nickel plating. Tripoli leaves a sort of matt finish on the workpiece, that you can see in the top picture. Look at how the handle is not reflected very well.
The second from the top picture is a pic of my crowded workbench. The little black specks are from the compound that was stuck in the grooves...I dug all that caked on polish out with scribers and that old standby, the thumbnail. It takes about a half hour to clean the tripoli off the workpiece in order to prepare it for the rouge.
The bottom two pictures show what a difference an hour with fine rouge makes to the looks of the workpiece. You can see the reflection of the the file and the handle quite well. Its still not as shiny as I would like, but it is good enough to plate. The nickel plating will of course make it look like a mirror. It is a bad habit to rely on the final plate to take rough spots out...because of course, it won't! In fact, due to the nature of the plating process, rough spots might provide "seeds" for tiny crystals of nickel. That would leave frosty parts on the workpiece which might not be able to be polished away! So I try to get it as shiny as I can before I have it plated.
The pieces all need to be "electro cleaned" in Tri Sodium Phosphate before being sent to the platers. A lot more dirt comes out in solution at that time. Not much to see in a photo though....a photo of the electrocleaning process would pretty much look like two wires going into a bucket of soap suds. The plateing has to be done within a day of the electrocleaning or else the surface will start to get a microscopically thin layer of oxide on it. This oxide does not conduct electricity, so if you wait too long between cleaning and plating, you get a mottled surface.
Now I just hope nobody asks me about the handcuffs on the workbench....grin!

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