10thumbs
spending too much on rocks
I want to be reincarnated as a dog.
Member since March 2009
Posts: 480
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Post by 10thumbs on Aug 9, 2009 8:33:42 GMT -5
I started using my new 3000 grit belt for the first time yesterday. I was surprised to still see scratches under 10x magnification. Did I not dress the belt long enough or are 6 micron scratches visible under 10x magnification?
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Aug 9, 2009 10:39:33 GMT -5
Just to be sure your looking at the right grade of scatches, get a glass jar (or window glass) and grind the side of it with each grit so you can compare them to the rocks scratches. Once you've seen each grit on clear glass it's easy to remember them.
This also let's you see if you have dressed to wheels properly.
Dr Joe
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mc2
fully equipped rock polisher
Member since April 2009
Posts: 1,147
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Post by mc2 on Aug 9, 2009 22:40:57 GMT -5
What an excellent idea! Never would have thought of that, thanks!!
Mike
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10thumbs
spending too much on rocks
I want to be reincarnated as a dog.
Member since March 2009
Posts: 480
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Post by 10thumbs on Aug 10, 2009 8:23:50 GMT -5
What an excellent idea! Never would have thought of that, thanks!! Ditto for me. Thanks for the great idea, Dr Joe.
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Aug 10, 2009 12:32:34 GMT -5
You can say your really good when you can take a piece of glass thru all the grits and have it as clear as when you started. ;D
Dr Joe
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10thumbs
spending too much on rocks
I want to be reincarnated as a dog.
Member since March 2009
Posts: 480
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Post by 10thumbs on Aug 16, 2009 18:30:17 GMT -5
I'm definitely doing something wrong. I am causing scratches with the 3000 belt. I don't know if I'm pressing too hard but a bunch of my favorites have to be downgraded back to lower belts to get the scratches back out. I thought you'd only have deep scratches if you failed to dress the belt initially. I've dressed it twice now per the instructions that came with the belt. I don't know what is happening but I'm mighty disappointed. I was looking forward to going to polish with some of these.
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10thumbs
spending too much on rocks
I want to be reincarnated as a dog.
Member since March 2009
Posts: 480
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Post by 10thumbs on Aug 17, 2009 7:38:01 GMT -5
I tried a few more last night. Same results. I can only assume that the belt was contaminated somehow. I have the water set such that there is a slight spray or mist coming off the belt so I don't it's that I did not have enough water. I took the belt off and cleaned the expando drum. Finally I went over the belt with my 10x magnifying glass to see if anything is stuck to it. I did not find any smoking gun as far as something that coiuld have been causing the scratches. WTF?!!!
I'm a little disappointed how worn it looked under magnification too.
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Aug 17, 2009 7:42:19 GMT -5
Have you tried the glass trick yet? Try it on the 3k belt by touching the glass straight to the belt without moving it around and see if you get a scratch or groove in one place vs the rest of the surface. If you do then you can trace back the contaminated area and find the bit causing all the problems. It's easy to get a bit of grit embedded inn a belt's surface (also behind the belt!) and cause all sorts of grief. Sometimes there is a tail (like a comet) following the piece of grit on the belt too.
On new belts it's not usually contamination but a conglomeration of grit causing the problem.
How did they tell you to dress the belt?
Keep us posted on what you find (or don't find).
Dr Joe
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Wolfden
fully equipped rock polisher
Member since November 2007
Posts: 1,368
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Post by Wolfden on Aug 17, 2009 15:22:17 GMT -5
I like the glass trick .. i may have to get a few pieces and run them through each grit ,,
Thanks Doc
Wolf
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Aug 17, 2009 19:46:07 GMT -5
That's what this place is all about... Sharing info ;D
Dr Joe
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cman
starting to spend too much on rocks
Member since August 2009
Posts: 207
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Post by cman on Aug 18, 2009 16:05:26 GMT -5
DR. Joe Your the man for mentioning glass testing. Now to find some glass. Maybe I can break a window. Ah found a nice piece of glass. Didn't have to break a window. I will do this test in morning at club and keep for future checking of scratch's. Later
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Aug 18, 2009 17:59:29 GMT -5
There's always the neighbors window ;D Use a baseball and blame those darn kids down the block (or terrorists).
Dr Joe
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