Polishing the expander rod

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azar

azar

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I've been wanting to polish up the expanders in my RCBS two die sets. I've seen various posts from different people about the best way to go about this. I picked up some 400 grit and 600 grit "wet sandpaper" from the hardware store on Saturday. I also have JB Bore paste and Maas metal polish. I was thinking of chucking the expander rods right into my drill and using the 600 grit paper to smooth it up. I'm not sure what the "grit" of the JB Bore paste or the Maas metal polish would be, but probably finer than 600?

What have you used to polish your expander rods? What worked best?
 
The 600 grit will be smoother than it is now. If you want to polish it further it won't hurt. I don't myself.
 
I wouldn't use the 400 grit. It's too coarse. Use the 600 wetted with oil, and chuck the rod in your variable speed drill. Go lightly and not alot. Just use the 600 until you see a slight improvement in the smoothness. After that you can use JB or Flitz on a cotton patch, and really bring it to a nice shine. I do it on mine, and it works well. Good luck.
 
If I use the 600 grit sandpaper, do I use any oil or water with it? Or use it dry?

Oh, I see Fatelvis beat me to it and suggested using oil.
 
I just polished some in the lathe. Didn't have any super-fine paper, so I used a cloth strip with valve grind compound, followed by a metal polish compound. It smoothed out the ridges.

600 paper with a light oil should work. If you have a polish or rouge to follow with it should work better. Biggest issue is to keep the pressure even across the surface, which was why I used a cloth strip.
 
I use a 6" muslim wheel on the grinder loaded with black compound. Next step if you wanted to "polish" it would maybe be green or white (red's too fine) but black did the job fine.
 
You don't have to polish all the ridges out. It will improve a lot just knocking the high spots down. I'm a grind engineer for a living (solar silicon) and you'd be amazed what a little elbow grease will do to your surface finish even though it doesn't look significant. We polished a silicon ingot with 320 grit scotchbrite like wheel from an Ra roughness of 0.10-0.15microns and achieved a 0.04 micron Ra finish.

And my grinding process employs about a 1500 grit grind wheel. We could still see the grind pattern clear as day, but the roughness meter didn't lie. The result, we just knocked off the high spots and it made it nearly as smooth as window glass, which is about 0.02 micron Ra. I was impressed as we did not anticipate it getting that much better.

Sorry, geeking out a bit.

jeepmor
 
Go to your local auto supply store and get a sheet of wet/dry 2000 grit sandpaper, wet it, chuck the rod in your drill, and polish away. That's all you'll need. :)
 
Yeah, I already picked up some 400 and 600 grit wet/dry paper. I think I'll probably return it today. While I think the 600 grit would work okay, others I have talked too thought it would be possible for the 600 grit to remove some measurable amount of material.

I think I'll use some JB Bore Paste on a cloth patch to start and maybe finish with the Maas metal polish.

I appreciate everyone's suggestions.
 
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