polishing marble
Close
Login to Your Account
Likes Likes:  0
Page 1 of 2 12 LastLast
Results 1 to 20 of 36
  1. #1
    Join Date
    Oct 2003
    Location
    ohio
    Posts
    1,342
    Post Thanks / Like
    Likes (Given)
    55
    Likes (Received)
    135

    Post

    I need to polish a couple pieces of marble.I tried to smooth a piece with 400 wet sanded and then tried to buff it with auto rubbing compound.Didnt do good enough.I then tried using comet and water and still didnt bring a nice shine.I am using an automotive polisher and really laying into it.I figured this would be easy but am seeing that I was wrong.Any suggestions on how to get a highend finish on marble?
    Jim

  2. #2
    Join Date
    Jul 2004
    Location
    Vicksburg, MS
    Posts
    4,931
    Post Thanks / Like
    Likes (Given)
    30
    Likes (Received)
    259

    Post

    You need diamond abrasives for stone, used wet. My neighbor is in the stone business. He uses diamond wheels all the way up to 2000 grit.

  3. #3
    Join Date
    Sep 2002
    Location
    northeast
    Posts
    1,721
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    7

    Post

    I don't know how well tumbling transfers to polishing but 500 grit is considered a pre-polish with polishes being much finer. You may want to look into buffing compounds like tripoli, etc. I'm not sure which would be appropriate for marble though. Den

  4. #4
    Join Date
    Dec 2004
    Location
    SF Bay Area
    Posts
    2,188
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    57

    Post

    Most importantly, I think you need more of a grit gradient. Rubbing compound is equivalent to a grit of probably 5000 or so. You'd need to work forever to eliminate 400 grit scratches with 5000 grit abrasive.

    The typical technique is to use diamond pads, for example I've used these:

    Flex diamond pads

    but to get a really good finish you can't skip many steps, just as with polishing metal or anything. You probably don't want to spend $400 to get a good new set, however.

    Try Ebay. Here's a complete set that is closing in 36 hours and currently on $35:

    diamond pads on ebay

    Also, diamond is surely not required for marble, given its softness. Someone might make pads like those above from less expensive abrasives (that is, specifially for marble but not granite and harder stones), but I'm not aware of them.

    However, you can get aluminum oxide or silicon carbide sheet abrasives for about a buck and up each, and these can be had in discs from 4" to 16" diameter, sheets, belts, with or without adhesive, etc. 3M makes about 5,000 different configurations. I am pretty sure silicon carbide would be fine for marble.

    Standard gray wet-or-dry paper is silicon carbide, (I'm assuming that's what you used). The same thing is available up to a grit equivalent of about 100,000 (finer that 600 they grade by micron size, not 'grit') These materials are typically called "Lapping Films". 3M only sells them in bulk packages of 10 or 50 or 100, but there are a few places that will sell individual sheets. Here's where I buy some of mine (that I use on metal):

    PSI - Precision Surfaces International

    The menu is complicated, but try following this:

    Online Store
    - Metallography
    -- Lapping Film Discs
    --- Presuure Sensitive Adhesives
    ----- [ then pick your size ]

    4" discs are $0.40 each from 30 to .3 micron. 30 micron is 600 grit. So you can get wet-or-dry paper from the hardware store up to 600 grit, and then go from there up to sub-micron ranges (.3 micon is like 100,000 grit and will produce optical finish) Realisitically, for marble you probably want to go up to 5 micron max (4000 grit), but this is a guess on my part.

    The guy at PSI is nice and helpful, although don't expect him to know about marble, because that's not his customer base. But if you've proven that wet-or-dry paper cuts marble fine, then these lapping films are sure to work because it's tha abrasive, just finer grades.

    Good luck!

  5. #5
    Join Date
    Apr 2003
    Location
    Stuart, FL, USA
    Posts
    173
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Post

    Mark, thats a great site, Ive been looking for 3M diamond files.

  6. #6
    Join Date
    Feb 2005
    Location
    TYNE AND WEAR, ENGLAND
    Posts
    2,517
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    15

    Post

    This is great reading. For the first time, I have a direct relationship with abrasive grit as I knew it and micron things.

    I have a different restoration job.
    I have two marble tops in my Spanish place.
    The kitchen worktop has small acid "burns" from - I guess- wine vinegar, lemon juice and the like.
    The acidic reaction has actually raised the surface in a few places.

    With limited space- air baggage allowance- what do I take with me to try to polish the damaged bits?

    My local monumental sculptur has suggested that I leave it.

    Norman

  7. #7
    Join Date
    Dec 2004
    Location
    SF Bay Area
    Posts
    2,188
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    57

    Post

    Norman, I don't know anything about polishing marble per se, and I can't say what to do about the spots. I've polished granite and concrete, which are much harder, but it's not hard with an good sander and those diamond pads. For marble touch up, perhaps a little random orbital palm sander would be good, or even just by hand. You might start with the finest grit and work backwards toward a larger grit until you see some effect. But I suspect you can't polish away discoloration. Marble is porous, and it sounds like you've probably got some chemical reaction
    from the acid.
    Btw- as to grit vs micron comparisons, three's lots of websites with tables. Just google around with terms like "grit micron". Here's a pretty good one that also compares different rating standards and also some common abrasives:

    grit comparison table

  8. #8
    Join Date
    Feb 2005
    Location
    TYNE AND WEAR, ENGLAND
    Posts
    2,517
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    15

    Post

    Mark,
    That was extremely kind of you to point me in the right direction.

    Hopefully, having a copy of the grit chart will not only help with the problem but act as a sort of reference for my activities with a tool and cutter grinder and a lathe restoration.

    Again, my thanks

    Norman

  9. #9
    Join Date
    Sep 2002
    Location
    Seattle, WA. USA
    Posts
    1,107
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    3

    Post

    How dangerous is stuff like Marble, Concrete, and Granite to grind?

    Sincerely,
    Bob Welland

  10. #10
    Join Date
    Dec 2004
    Location
    SF Bay Area
    Posts
    2,188
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    57

    Post

    Dangerous in what way? You mean dust perhaps? Most stone grinding is done wet, so there's no dust. Dry grinding would obviously produce lots of dust. I doubt any of it is directly toxic, but breathing fine dust over prolonged periods is certainly bad for you, eg. can lead to silicosis, etc.

    I don't know of any other dangers, except normal dangers associated with operating tools. Probably a lot less dangerous than being in a machine shop, given that in grinding stone there are are sharp edges, heavy rotating objects, etc.

    Of course using electrical tools in a wet environment requires certain precautions, ideally using tools with grounding wires connected to GFCI circuits. A lot of electrical sanders these days are double insulated and have no grounding wire. I don't know what happens when you squirt water inside a tool like this, but I assume that it is not risk free for the operator. Personally, I prefer to use air tools in wet environments, since then you don't even have to think about it.

  11. #11
    Join Date
    Apr 2002
    Location
    Syracuse, NY USA
    Posts
    9,691
    Post Thanks / Like
    Likes (Given)
    19
    Likes (Received)
    579

    Post

    my sculpture teacher in art school worked with marble and serpentine [old grave stones he got from cemeteries when they converted to flat plaques. THe serpentine is extremly hard and took foreever to carve even with air tools, but it polished easily it seamed [I wasn't doing it] the marble was fairly hard because it was old bur carved easily with hand chisels, really carves easier than hard wood in many ways. But I remember him sanding with wet and dry paper for days and days on a small piece, but he would get a fairly high polish. I know he used only wet and dry paper.
    The Egyptians carved the sepentine with a second piece with just rubbing it, they had no hard metals, so when you see a 20 ton serpentine sculpture from Egypt, just remember that there must be tens or hundreds of man years in it.

  12. #12
    Join Date
    Oct 2003
    Location
    ohio
    Posts
    1,342
    Post Thanks / Like
    Likes (Given)
    55
    Likes (Received)
    135

    Post

    well I am in the dog house till I get it right.This is what is up.I laid marble tile in the master bath last weekend.The last two pieces at the doorway were giving me problems getting them level.(I am a bit too fussy)I managed to break the mating corners on both tiles when I was pressing too hard on them.I adjusted the pieces and finished setting them in the morter.I had rented the wet saw the day before and had all pieces precut so I couldnt recut a couple of pieces.
    Well there is a slight sharp edge sticking up at the joint where the tile broke.I tell wife not to worry I can "fix" it. :rolleyes: That is when I tried to wet sand it and polish.She said to leave it alone but I had been challenged by my damn fussiness. [img]smile.gif[/img] I now have the dull spot right in the doorway that is the size off a baseball. I have wet or dry paper up to 2000 grit for sanding auto clearcoat so I will work my way up to that.I figured you were wondering what I was into so there it is.If it doesnt ever shine like it was originally I am going to hear "I told you so" [img]tongue.gif[/img] for a long time Thanks Guys..

  13. #13
    Join Date
    Oct 2003
    Location
    East Peoria, IL, USA
    Posts
    5,386
    Post Thanks / Like
    Likes (Given)
    337
    Likes (Received)
    789

    Post

    I recently talked to some marble and granite installers. they said they repair acid etching and stains on site with the wet diamond pads, and that they polish bull nose trim and stuff with them too. pretty much the only thing the use for finishing anything. the ebay pads look to be a good deal.

  14. #14
    Join Date
    Oct 2003
    Location
    ohio
    Posts
    1,342
    Post Thanks / Like
    Likes (Given)
    55
    Likes (Received)
    135

    Post

    I looked at the ebay pads.What do you mount them On?A 4" angle grinder?

  15. #15
    Join Date
    Sep 2004
    Location
    Pt. Pierre Trinidad (Work)
    Posts
    89
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    23

    Post

    Norman, the thing that I would worry about in your situation would be blending the newly polished spots into the rest of the counter. The rest of the counter top is naturally have picked up a random finish from things being moved across it over time. When you step in and try to bring a few small spots up to a fresh high polish they may look even more glaring then when you started. Then you only option would be to try and polish out the rest of the top no fun. You may want to just leave it alone. My 2c.

  16. #16
    Join Date
    Dec 2004
    Location
    SF Bay Area
    Posts
    2,188
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    57

    Post

    The diamond pads are velcro-like on the back. I'm pretty sure they will stick to a standard 5" hook-and-loop pad. I have a hook-and-loop pad that I think is intended specially for these pads and the hooks are more heavy duty than the hooks on a regular sanding pad (for hook-and-loop sandpaper discs), but I think a regular hook-and-loop sanding pad will probably work fine.

    It seems like your other choice is to replace the broken tile? Did you consider that? Can't you just break out the defective one, cut new ones to fit, and re-set them? Might be more predictable (though I suspect you'd have fine results with grinding)

  17. #17
    Join Date
    Jun 2004
    Location
    Tualatin, OR USA
    Posts
    131
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Post

    I have two sets of the diamond pads that I use on granite. The ones on ebay look like a reasonable set and the price looks great. However, a normal 4" or 4 1/2" angle grinder is way too fast to run these pads. They should run somewhere below about 2500 rpm or you just burn the heck out of the rubber and run a strong risk of pulling the pad loose and frisbeeing it over the horizon. I know because I tried it and did that once. I've since picked up a low speed polisher that runs the pads really nice. For backing pads I have three. One is a hard rubber disk with hook and loop made for them, one is a foam backed hook and loop pad made for them and one is a foam backed hook and loop I picked upat a woodworking supply. They all work well, but the hard rubber pad works best to keep flat surfaces flat and sharp corners sharp.

    For detailed polishing, lapidary abrasives work well. Specifically silicon carbide loose abrasives on soft leather in grit steps up to 5000 followed by tin oxide or cerium oxide polishing abrasive. The cerium oxide is green and can stain porous or cracked marble though.

  18. #18
    Join Date
    Apr 2004
    Location
    Antelope Valley,Calif.,US of A
    Posts
    115
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

  19. #19
    Join Date
    Mar 2005
    Location
    Somerset, UK
    Posts
    5,023
    Post Thanks / Like
    Likes (Given)
    508
    Likes (Received)
    1734

    Post

    Somewhat OT, but while you’re laboriously polishing your stone, spare a thought for the people who whittled this church out of solid granite 800 years ago:-

    http://www.gisdevelopment.net/applic...rchg0012pf.htm

  20. #20
    Join Date
    Dec 2004
    Location
    SF Bay Area
    Posts
    2,188
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    57

    Post

    I would agree that you don't want to run these pads on typical 10,000+ rpm right angle grinder, but for occasional use they work fine on 5,000-7,500 rpm disc sanders. For example, I run them my 7,500 rpm Fein random orbit sander without any problem. Those are no-load ratings and most sanders drop to probably half the rated speed once any load is applied. Of course, you have to keep them wet.

    But if you're doing it regularly, of course you want a tool designed for the job. If you want to buy a tool for the job, here's a good starting point:
    Granite City Tools


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •