meta7
starting to spend too much on rocks
Member since June 2010
Posts: 164
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Post by meta7 on Oct 22, 2010 18:05:54 GMT -5
I am looking to make some 10" flat-lap discs that will be put on a magnetic head. I plan on using epoxy/diamond powder. I'm not sure if there should be a softer surface on top of the metal disc for the diamond powder to go on or if the diamond powder should be glued to the metal disk. Looking for any help/ideas about this process, including where to get 10" metal plates that will be attracted to magnets. Any thoughts or ideas are appreciated. Thanks, Dave
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Post by jakesrocks on Oct 22, 2010 18:14:56 GMT -5
Worn out 10" saw blades would probably work. What size arbor hole do you need ?
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meta7
starting to spend too much on rocks
Member since June 2010
Posts: 164
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Post by meta7 on Oct 22, 2010 18:23:09 GMT -5
any hole will do, because my head does not have a hole on it - it screws onto the shaft but the plate itself does not have a hole
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Post by jakesrocks on Oct 22, 2010 18:44:51 GMT -5
There's info somewhere on here about redoing diamond wheels. The same would probably work for discs. Now you just have to find a supply of worn out blades. I just gave away 4 of them that still had a little life left in them.
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meta7
starting to spend too much on rocks
Member since June 2010
Posts: 164
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Post by meta7 on Oct 22, 2010 18:54:34 GMT -5
would it be better to put a rubber pad on the blade and then put the diamond on the pad, or just glue to diamond straight to the blade?
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Post by jakesrocks on Oct 22, 2010 19:33:36 GMT -5
If you're going to use it as a flat lap, don't use rubber. I don't think you'll be able to bond diamond to rubber anyway.
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
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Post by drjo on Oct 22, 2010 19:34:11 GMT -5
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meta7
starting to spend too much on rocks
Member since June 2010
Posts: 164
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Post by meta7 on Oct 26, 2010 13:59:35 GMT -5
Dr. Joe,
Which would you recommend - the 1/8" or the 1/4"? This would be used for adhering diamond powder and epoxy 330 to it.
Also, is it better to use Nickle Plated Diamond Powder?
:-) Dave
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
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Post by drjo on Oct 26, 2010 17:08:37 GMT -5
1/8" for your first try, bonding to the pad may be tricky, plus the flex/cracking/peeling problem. Epoxy 330 is for non-porous surfaces.
Nickel plated (or bonded) is mainly used in the high heat sintering processes. If you can get it for the same price as plain it will last longer (but not cut as quickly) neither of which may even be noticeable in this instance.
Dr Joe
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Post by johnjsgems on Oct 26, 2010 22:53:56 GMT -5
I think the nickle mixture is used for plating or sintering as Dr. Joe said. I would use diamond powder if I was doing it.
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meta7
starting to spend too much on rocks
Member since June 2010
Posts: 164
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Post by meta7 on Oct 27, 2010 9:49:32 GMT -5
Is there a non-pourous type of surface that I can put on the disc and then bond the epoxy/diamond powder to that?
Also, I called Eastwind Diamond Abrasives to price out these felt discs and found out that they are selling Diamond Powder for 57 cents a carat, which I think is really good.
They sell most of the grits either in the pure form or with 30% Ni plating or with 55% Ni plating, all for 57 centsw a carat, minimum order 100 carats, each grit size must be at least 50 carats.
Dave
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Post by jakesrocks on Oct 27, 2010 10:25:08 GMT -5
Don't use the Ni mixture if you're bonding to a soft surface. Ni is applied to a hard metal surface, using very high temperatures. It welds itself to the metal surface. The straight diamond powder mixed with an epoxy which remains semi pliable after curing would be your best bet. 330 epoxy will cure much too hard, and may start to flake off with use. Contact an epoxy manufacturer, and see what they would suggest using.
Don
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Post by johnjsgems on Oct 27, 2010 11:06:51 GMT -5
I think Diamond Pacific uses a plastic compound for their Nova wheels. 57 cents is dirt cheap although those are large quantities. I get $10 for 5 carats. If you can picture electro pating, brazing or sintering (fusing into metal under high heat) you can see the need for the nickle/metal compound. For what you are doing there is no need for the metal compound.
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meta7
starting to spend too much on rocks
Member since June 2010
Posts: 164
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Post by meta7 on Oct 27, 2010 11:48:53 GMT -5
Could I bond the epoxy/diamond powder straight to the metal? If so, would it be better to use Ni plated for that?
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Post by jakesrocks on Oct 27, 2010 12:15:23 GMT -5
Yes and no. Yes to bonding straight to the metal. Rough the metal up with some coarse sandpaper first, to give the epoxy something to grip. And no to the Ni diamond powder. You won't gain anything, unless you have the special equipment needed to melt the Ni. Since both powders cost the same, get the straight diamond, and get more for your money. You'll have enough diamond to do 2 wheels, and probably more.
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