Refinishing Old Pen Barrels

[Inky-Republic]

I have some 0.5um diamond paste which I use for polishing microscope samples to a mirror finish.

 

Has anyone on this site tried to use fine diamond paste as an abrasive polish to refinish scratched pen barrels by hand?

 

I'm currently thinking of purchasing a couple of junk pens to try it out on, but if someone has had an epic fail with the stuff already, I won't bother.

[PaulS]

I hate to appear thick in front of thousands of people, but how do you polish a microscopic sample - f.ps. are, of course, vastly bigger so should be a lot easier, though possible your product might be intended for polishing a much harder material.

On the assumption you are bereft of replies, you might just go ahead and try rubbing a pen barrel with your paste and see what happens. Can't imagine the grit size is going to cause a problem, but possible there may be some issue with the carrier - depending on the constituents.

You might post pix of the results - on a pen. Wish you luck.

[Inky-Republic]

I hate to appear thick in front of thousands of people, but how do you polish a microscopic sample

 

Answer:

These are metallurgical samples mounted in bakelite. The idea is to examine the metal micro-structure using a special inverted microscope. This is to check that ferrous alloys have well formed carbon nodules and that they are evenly spread and spherical throughout the sample. You can also etch the sample with various acid based chemicals, so as to identify any undesirable formation of carbides and also to verify the relationship between ferrite and pearlite within the melt. To see these micro features clearly, the surface of the sample must be perfectly polished like a mirror, using increasing smaller paper grits and finishing off with an ultra fine diamond paste and soft felt. The mounted sample is about an inch across.

 

A perfectly flat water lubricated wheel is used for the initial grinding, then the platter is changed to a felt base. The fine diamond dust is suspended in a synthetic oil based slurry. Although ultra fine, it removes stock quite quickly and as long as it doesn't attack the pen barrel material, would polish out scratches with only a few turns. I'd probably make up a soft rag cover over a carefully sized wooden rod, so that I could rotate the pen barrel in a slow speed cordless drill.

 

Nice theory, but will have to try it out on a sample with little value.

[PaulS]

:-) - thanks for the explanation. Am I correct in thinking that 0.5um is five microns ? yes, agree, any old inexpensive pen will suffice for experimental purposes.

Edited April 26, 2019 by PaulS

[Inky-Republic]

No - in fact much finer at one half micron. I'm thinking that as long as the suspension material doesn't chemically attack the casing in any way, you should be able to achieve a super fine finish. I've actually used this paste on a hard plate to smooth up the action of a nib. Unfortunately it ended up rather too smooth and tended to skip. Once I used the nib for a while however, the surface textured up and it worked OK. One advantage of the paste is that it is easy to remove without harsh solvents, although of course you have to be thorough, or it will continue to do it's thing and wear material away!

[PaulS]

thanks - I should look more carefully at the position of the decimal point