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Post by tntmom on Dec 1, 2010 1:52:56 GMT -5
Can someone please tell me at what grit you can no longer see scratches of any kind with the NAKED eye?
Is it 325, 600 or 1200?
I've asked this question before but I haven't gotten a clear answer. I've been told to go to the next grit when I no longer see scratches from the previous grit. I'm not experienced enough to tell what scratches were made with what grit? I am working a cab by hand for the first time, instead of a tumbler, and do not know when to progress to the next stage. When (without a magnifying glass) should I see a semi-gloss finish. I thought it was 600 but I have been using the same grit for a couple of days and can't seem to get there. My stone is an agate so I assume it should be a decent stone to start out with. When I pull my rocks out of 500 grit in the tumbler they are already starting to shine. Should I go back to 325 or earlier? When the stone is dry I can still see minuscule scratches after the 600 grit. (looks great wet)
I am starting to get frustrated..... all of the beginning steps worked out so well. I can't figure out what step I messed up on!
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Post by sandsman1 on Dec 1, 2010 2:28:19 GMT -5
if you see very small scratches move to the next grit then dry the stone again and see if there still there if they are i usually go back 2 grits and start again sometimes when you shape the cab you will put some deep scratches in the stone that will keep commin back to haunt you -- make sure you dry them after each grit and look good
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Post by sandsman1 on Dec 1, 2010 2:32:37 GMT -5
i was just thinking you said your first stone are your wheels new they may need breaking in you could have some high spots on the wheels that are cutting faster and leaving deeper scratches take an old piece of something hard and go over each wheel with a little pressure and break the wheels in not with the edge of the stone use the flat part so it dont tear up the face gotta remember each grit puts smaller scratches in it till they get so small you cant see them-- moving to the next grit will also show if there are still any bigger scratches left from other grits -- id say 1200 befor you see much shine dry
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Post by parfive on Dec 1, 2010 4:04:22 GMT -5
“ . . . with the NAKED eye.”
I never rely on the naked eye, or my reading glasses, for that matter. Flaws you can’t or don’t see early on will stick out like a sore thumb when you polish the cab.
Get a 10x loupe – they’re only $10 - $15 and eliminate all the guesswork and frustration going back steps.
Don’t leave the 280 wheel until the cab looks flawless under the loupe. Every step after that becomes easy.
Rich
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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 Dec 1, 2010 8:58:37 GMT -5
Your using a Dremel and diamond paste aren't you? Break-in isn't much of an issue here. If you want to learn your scratches, get a piece of window glass and polish it in a 1 sq in area (for each) with each grit stage. This will give you a reference to work with. Then take one 2 sq in area and start out with your coarsest grit (which should scratch up the glass) and then work up all your grit stages till the glass is clear again. This will give you a good understanding of the whole grinding/polishing process. Not something many people want to do. Keep us posted on your progress. Dr Joe .
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Post by FrogAndBearCreations on Dec 1, 2010 9:50:31 GMT -5
I work each grit/mesh level untill no scratches stand out to the naked eye before moving to the next one and so on. Light touch and good stone rotation on the polishing surface and most of all very good lighting to check for scratches. Also most importantly is cleaning the stones and your hands very well before moving up to the next stage. One or two pieces of grit from a previous stage contaminating will leave scratches like crazy
depending on the type of stone I work from 220 all the way to 100,000. some stones don't need to go that far and get a hard shine at about 14,000 and the softer stuff does well up to 3,000 with a zam finish
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Post by tntmom on Dec 1, 2010 16:12:28 GMT -5
Thank you everyone! After reading everyone's feedback, I believe I rushed the 220 I prepolished with the 14,000 and although it is very shiny, scratches are everywhere! I am stepping back to the 220 and will stick with it until I can not see a single scratch. Rich, I have a lighted jewelry magnifier, I will look for it and put it to use! And yes Dr. Joe, I am using a felt bob and diamond paste with this stone. If I ever get this thing finished I will post a picture. Thanks again
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Post by FrogAndBearCreations on Dec 1, 2010 18:19:36 GMT -5
the finish should be very even with no scratches jumping out at you at each stage
if you did not get the scratches out from a previous stage then those will pop right up at you when you move up.
I used my fordom flex shaft with diamond polishing discs for years with good results but as I mentioned you need to be meticulous on cleaning when you go up in grit as its real easy to cross contaminate your polishing bobs and discs, I know from first hand experience!
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Post by tntmom on Dec 1, 2010 19:05:43 GMT -5
you need to be meticulous on cleaning when you go up in grit as its real easy to cross contaminate your polishing bobs and discs, I know from first hand experience! I am washing the stone in a paper bowl of warm soapy water between grits and using paper towels to dry and clean up. I'm not using any dishes, rags or towels because I don't want any grit in my washing machine or drains. I've learned from several people here, what a tiny bit of slurry can do to your pipes! Also each grit level tools have their own storage bag so I am being extra careful to not cross contaminate. Update: Yes, the 220 was where I made the mistake. I am in the process of redoing the 220 and am now noticing areas that have a matte finish with no visible scratches. When finished I will check with a magnifier. I am finding that going back and re-sanding is a lot easier this time because the stone was pre-polished in the 14k. It is very easy to see areas that I am missing because they are still shiny. Does anyone polish between grits for this reason? ~Kristine
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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 Dec 2, 2010 0:09:27 GMT -5
No, but rubbing a pencil over the surface before each level will do a similar thing.
Dr Joe
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Post by Woodyrock on Dec 2, 2010 2:04:10 GMT -5
Kristine: Another method to use is change direction of your cab by 90 degrees between each grit. Check for scratches with the cab dry...not towel dry but really dry. I use a Good Will hair dryer. If there is only a small amount of moisture present, it will fill in the scratches so you do not see them. Every time I get lazy, and do not use the hair dryer, I end up redoing the cab to sand out scratches. Woody
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bgast1
fully equipped rock polisher
Member since July 2010
Posts: 1,076
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Post by bgast1 on Dec 2, 2010 15:44:05 GMT -5
May I chime in and ask a question also? How much do you have to worry about cross contamination when working with a flat lap. I have an Ameritool that starts at 180, 325, 600, 1200 then polish on hard felt disc with 14,000 diamond paste.
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