THIS STEEL is making me crazy, WHY CAN'T I get a MIRROR POLISH ?!!!!!

ElementalBreakdown

ElementalBreakdown

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Jul 14, 2020
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I have been trying to get a perfect mirror polish on this small keychain prybar/tool from WE/Civivi and I can NOT get the final scratches polished out.
Not only have I used the highest grit wet/dry paper and then hit it with a Dremel at 25,000+ RPM's using a variety of different rotary tool tips loaded with .25 micron enhanced diamond paste.

I can NOT get it polished any further, and I have no idea where to go from here.

Take a look at the pics and let me know if you have any ideas!

diamond polish.jpeg steel 2.jpeg no mirror steel 1.jpeg
 
Those are deep scratches/pits. You will need to drop DOWN to something like 400 or 600 grit to get them out, THEN work your way up.

All you are doing with the higher grits and polish is polishing around the rough marks. You need to sand through them.
 
Thanks, I had the feeling that someone was going to say that. It's OK though, I have had so little time lately that this project has been almost like a meditation type thing for 15 or 20 minutes a day, so going backwards a bit isn't all that frustrating.

I thought that eventually, given enough time, that using the super high grit would accomplish the same thing except Much slower.
Thanks for confirming that's not the way it works : )
 
Polishing with wet/dry SiC paper is all about the sequence of gradual grit steps, like 220 > 320 > 400 > 600 > 800 > etc.

SiC sandpaper's grit also breaks down pretty fast as it works, meaning the grit gets even finer. So, if you start from the beginning, trying to polish out coarse scratches with a high grit like 1000 or so, it effectlvely works to a much finer finish than rated, once it starts breaking down. This also means it takes exponentially longer in time, to work out all those coarse scratches. AND, as the paper loads up with metal dust (swarf), it'll make the work even slower. This is why the sequence is so important - you want to start with a grit coarse enough to QUICKLY refine the deep scratches, before the grit begins to break down and before it loads up too much. Then move on to the next grit step and do the same again, refining further each time. If that's done fully within each grit step, by the time you get up to maybe ~ 800 grit or so, the polish will start coming up fast and will finish out much more easily. Go through 2000 or so, then use the polishing pastes after that.
 
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ElementalBreakdown said:
and then hit it with a Dremel at 25,000+ RPM's using a variety of different rotary tool tips loaded with .25 micron enhanced diamond paste.
Click to expand...

Sounds like you may be over-polishing. From the Uddeholm Polishing Manual.

VtQUY8E.png
 
if the pits weren't there before, then they do come from pitting ( i call it micro-pitting ). micro-pitting can be observed from early on and is a pita. i have hundreds of hours of experience with (manual and powered) mirror polishing and micro pitting, and after all my experience, i decided to call it quits BECAUSE of the micro pitting phenomenon.

micro pitting can be reduced to a minimum (e.g. by slow polishing, light-pressure polishing, short-time polishing) but under certain lighting conditions you'll still be able to see micro and nano scratch lines (and these can come from the metal powder in your polishing cloth!). annoying. so you try to polish them out with some measure. and then the scratches are gone and gonner but orange peel has started to form, and that's the start of micro pitting, etc.

very frustrating. and not fun or satisfying. for 0.25micron you'd also need a matching ubersoft cloth. and slow speeds. can't do with dremel.

"perfect mirror polishing" is basically science and art, not a skill.

my recommendation: dremel out the ugly pits , resurface to a homogeneous look, and then leave it like that. it is time to move on.
 
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THANK YOU so much. This turned into a nightmare- thought I would be able to send this out in a month and now several months later I was still struggling. I appreciate the insight. I am calling it quits too- just going to do a little engraving and add some of my super glow and send it on its way.
Thanks again amigo!
 
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