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Author Topic: Recommendations sought for 3k lap -- Cu vs Sn vs Zn  (Read 3320 times)

ianRobinson

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Recommendations sought for 3k lap -- Cu vs Sn vs Zn
« on: January 24, 2018, 08:53:59 AM »
Hi Folks

I am looking to get a 3k lap for self charging, I am presently using 6k on copper then 1k as prepolish but am hoping that 3K will leave out a stage on sapphire. I seek suggestions on copper vs zinc or tin. I do have an old batt lap but am not sure about my skill with a lathe to resurface as an accident left the surface scored..

I have looked at the zinc+ from gearloose but would welcome alternate suggestions.
Thanks

Rusted

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Re: Recommendations sought for 3k lap -- Cu vs Sn vs Zn
« Reply #1 on: January 24, 2018, 10:25:20 AM »
I use all of your suggestions and there's not really a heap of difference.
I would go copper for the cutting stages 1K,  3K, even 14K. use lubrication on it, I use WD40 or Inox for lubrication, just a tiny squirt every so often when its starting to get gummy, if its really gooey squirt and wipe off with a tissue.

A decent cheap substitute for a copper lap is a piece of circuit board, available from your local hobby electronics shop. They last a surprisingly long time.

jaseee

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Re: Recommendations sought for 3k lap -- Cu vs Sn vs Zn
« Reply #2 on: January 24, 2018, 06:12:21 PM »
You can use both sides of a batt lap. So just flip it charge with 3k and go

Aussie Sapphire

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Re: Recommendations sought for 3k lap -- Cu vs Sn vs Zn
« Reply #3 on: January 28, 2018, 08:06:20 AM »
If considering zinc, it is a bit more aggressive so would recommend using this one with #8000 diamond for similar result with #3000 on tin or copper.


The tin is probably the more common one these days but they are expensive compared to the laminated copper laps (similar cost to solid copper) so depends if budget is an issue.


You CAN use both sides of a BATT (or similar) lap but you need to be extremely careful not to contaminate either side.  To be honest, I would suggest using two separate laps for convenience and less risk of contamination unless you are on a very tight budget.


If your old BATT lap is good on the other side and clean, then definitely try it with the #3000 - might save buying another.


cheers
Leah



Aussie Sapphire - The Lapidary Warehouse

MakkyBrown

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Re: Recommendations sought for 3k lap -- Cu vs Sn vs Zn
« Reply #4 on: January 28, 2018, 09:13:40 AM »
My tin lap is my favorite polishing lap, can polish anything and never scratches. I also lightly knurl it before loading.
Also for me it's a pain in the using two sides. What I do is cover the second side with clear contact(like you cover books with) so it wont get contaminated. Then can remove and lap is clean if I decide to change sides after wearing/contaminating the used side.

Buch Metter

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Re: Recommendations sought for 3k lap -- Cu vs Sn vs Zn
« Reply #5 on: March 29, 2018, 10:12:39 AM »
8k diamond powder is essential for prepolish on sapphire, they are a married item.
Absinthe makes the heart grow fonder

FlashGP

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Re: Recommendations sought for 3k lap -- Cu vs Sn vs Zn
« Reply #6 on: April 04, 2018, 10:59:30 PM »
I have two zinc laps and a cu lap.  One Zn lap charged with 3k diamond and the other 2 charged with 8k diamond.

I use the Zn 3k for cutting in many of the smaller facets then prepolish with 8k.  On a recent comp stone with 1 index knotch between facets, I cut in the facets with Zn 8k combo.  They cut too quickly with 3k.

This way I don't need to worry about subsurface damage.  With quartz I lubricatewith water.  Otherwise I continuously clean with snake oil on a makeup removal pad.

if your lap gets sticky too much swarf is building up and can scratch your work, or slow down cutting. The lap cuts much better if the swarf is cleaned off continuously.  Hence cutting with water on the 3k Zn lap.

Regards Gordon
« Last Edit: April 04, 2018, 11:02:22 PM by FlashGP »
Yours Sincerely
Flash (Gordon)

 

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