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#1

wandwaver
Newbie
Joined: 17 July 2018
Posts: 6
Newbie
27 July 2020 09:20 am

Hi my friend is having trouble removing scratches when cutting a sapphire any tips Thanks ... wandwaver gemstone

#2

Wally69
Member
From: Sydney
Joined: 13 December 2013
Posts: 3,509
Member
27 July 2020 10:01 am

Most common problem is too much diamond grit, wipe off excess with a tissue.

Try lower speed

2 users like this post: pinfire opals, goody2shoes

#3

Pat Hogen
Member
Joined: 02 January 2018
Posts: 336
Member
27 July 2020 10:43 am

Remove swarf and less pressure on the stone when polishing.


Absinthe makes the heart grow fonder

#4

wandwaver
Newbie
Joined: 17 July 2018
Posts: 6
Newbie
27 July 2020 02:11 pm

Pat Hogen wrote:

Remove swarf and less pressure on the stone when polishing.

What polish do you use Pat ?? have you heard of tripoli ??

#5

Pat Hogen
Member
Joined: 02 January 2018
Posts: 336
Member
27 July 2020 05:58 pm

Wandwaver-

Polish: Diamond, I use nothing but diamond powder, 3k > 8k > 60k > 100K spritz for sharp finish, lightly and quickly.

Tripoli is for the lesser of two weevils. Better off in tumblers.

Last edited by Pat Hogen (27 July 2020 05:59 pm)


Absinthe makes the heart grow fonder

#6

Moth
Member
Joined: 17 April 2017
Posts: 40
Member
21 August 2020 12:32 pm

I'm with the others - the most usual cause of scratching is contamination and that can occur from an external source (Swarf, failing to clean the stone from the previous lap, contamination on the polishing lap, or a build up of too much excess polish combined with a 'heavy hand').
Suggest a final cut at 1200, a pre-polish at 8000 and a final polish at 50,000 or 100,000 - not charging your polishing laps with too much material(making sure it is reasonably evenly spread on the lap) and ensuring you clean your hands then clean the stone at each sequence. Work at lowest speed when polishing.

Best of luck.

#7

geowork
Newbie
Joined: 01 August 2016
Posts: 2
Newbie
21 August 2020 07:30 pm

All of the above, and make sure after prepolish there are no visible scratches.

#8

wandwaver
Newbie
Joined: 17 July 2018
Posts: 6
Newbie
30 August 2020 10:49 am

Thanks big_smile

#9

Dihusky
Member
From: Gold Coast, QLD
Joined: 16 June 2017
Posts: 1,519
Member
31 August 2020 09:41 am

I know this is about scratching, but also make sure your pre-polish and polish laps are flat, then the stone will polish fast. I have my polish lap micro-grooved as well, it's Tin and I was cautious about doing this at first, but once done with a knurling roller and dressed off with 600 wet & dry on glass, the polishing speed increased dramatically.

1598827031_tin-polishing-lap-surface.jpg

I use this on virtually all material including the quartz's, the only material I found that it's no good for is opal, scratches badly.

The other plus with the surface is virtually no squeaking on tables. smile


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