A new finishing technique

galadduin

galadduin

Joined
Dec 25, 2004
Messages
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I had some grits left from mirror making for amateur astronomy. I have made one mirror 5-6 years ago but I had a 10" mirror blank left. I decided to finish some knives with these grits, sanded on the glass. It leaves a nice sparkling gray, like sandblasted finish. The knives are RWL34 HTed and rough ground to 80 grit on belt.The order I will go: 80 - 120 - 220 SiC grits. Then 30 - 15 - 5 micron AlO grits. Then finish with 3 micron Cerium Oxide... I'll post the results as I go further...

The knife pic at the attachment is sanded on 80 grit only. As I go down to 3 micron it will be smoother but the sparkle gray will remain... (I have tested the 3 micron finish on a small piece)
 

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That's a pretty unique approach toward finishing a blade, cant wait to see the progression pictures. :thumbup:
 
WalterDavis said:
Looks like it should come out pretty nice!
Click to expand...

Thanks Walter,
I'm now sanding at 120 grit, it is looking nicer and nicer as I sand. It is not similar to sand paper sanding as it doesn't remove material as it should, as it removes the previous grit marks it stops to grind the blade, instead it starts to grind the glass underneath :p. And it is progressing really fast, compared to sand paper. I've noticed the amount of water and amount of grit changes the result of finish. If I put too much grit and little water it starts to make more sparkling dots, if I reduce the grit and make it more slurry it starts to grind with directional scratches in addition of dots...
 
I just finished the 120 grit. Sun is going down here but I managed to catch a photo at the last moments of sunlight. In lightbox it does look like etched blade but under sun the shiny dots are easily visible.
I decided to finish that way as I was trying to find a way to sand things real flat. It is sanding things real flat as you are not sanding the steel but also the glass, at a random movement both surfaces are going flatter and flatter. At the finer grits there is a nice vacuum between blade and glass. At 3 micron the glass is polished back so you start with a good flat surface again :D
nyrtc.jpg


121tu39.jpg


edit: I'll continue to sand tomorrow from 220 grit. Will post progress pics at each grit...
 
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