# Help on sanding down stone pool coping?



## shadysprings (Mar 28, 2009)

Hey Masons,
I did some pool electrical repair and being asked if I can help sand/grind down a couple pieces of stone tile coping that has sharp edges.

Anyone know if this can be done? And what's the best way? I'm doing it for free so hoping to not spend too much or any money?

Here's a picture of what I'm trying to round off or bullnose.









I think rock is quartz? But I don't really know. It's pretty hard though. Not like sandstone.


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## Captainsls (Nov 8, 2007)

The picture doesn’t show the stone too well, but a full-nose bit for an angle grinder might give the profile they are after. The issues I would foresee are 1) it becoming a much larger task than you anticipate and 2) the texture left by grinding/profiling wont match up to the rest of the stone.


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## shadysprings (Mar 28, 2009)

Captainsls said:


> The picture doesn’t show the stone too well, but a full-nose bit for an angle grinder might give the profile they are after. The issues I would foresee are 1) it becoming a much larger task than you anticipate and 2) the texture left by grinding/profiling wont match up to the rest of the stone.


I can take a better picture. would a profile shot be better, or just a closer look at the stone.

When you say full-nose bit on an angle grinder, is this like a router setup? Ar we talking some kind of diamond bit or something?


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## Captainsls (Nov 8, 2007)

Something like this is what I was thinking:

http://www.mkdiamonddirect.com/product.sc?productId=1717&categoryId=131

Course you could half-nose it as well depending on the bit you purchase.


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## shadysprings (Mar 28, 2009)

Captainsls said:


> Something like this is what I was thinking:
> 
> http://www.mkdiamonddirect.com/product.sc?productId=1717&categoryId=131
> 
> Course you could half-nose it as well depending on the bit you purchase.


i see thanks. the stone thickness is 1" so i see there are 3cm full bullnose bits. Do you have any idea if these bits will hold up to this hard stone? i assume you keep it wet. at $200 a bit, I can't afford much more than one of them.

Any idea if there is anything cheaper. Maybe just a way to "sand" off the sharp edges?


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## Captainsls (Nov 8, 2007)

I have not used them myself. I have a friend that makes his own bullnose for travertine coping and he uses something to that effect. 

This would be for milling all of the coping on the entire pool though. If you just had one or two offending pieces, I might just take the angle grinder with a masonry blade and smooth 'em out just a bit. Perhaps pick up a piece of the same stone at a local supplier and give it a test run first though just to see if you are happy with the results.


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## stonecutter (May 13, 2010)

I do a lot of custom on-site fabrication with all kinds of stone including making and profiling pool coping. The biggest challenge you will have with a milling machine like that MK is that the surface and the edge of the stone will prevent the guide from sliding smoothly along as you work it...this will effect the profile. A hand held angle grinder was mentioned but you want one that is wet feed and variable speed..this will keep you from burning up an expensive profilerbit . Alpha,makita and metebo some very good brands. Alpha makes a profiler called a "B" type with different sizes for round-over or bullnose and are priced accordingly. They travel along the top of the stone with a nylon guide and grind into the edge. Since the guide only rests on a small portion of the stone it is less of a problem than a full guide set-up. If you need to you can touch up the profile with a diamond cup grinder..but be extremely cautious and only use one that is fine grain to avoid overshaping. You wil have to polish or sand the edge after you profile because the grind with be lighter than the rest of the stone..similar to what happens whe you chisel or cut stone. Hand diamond pads work well for finishing or if the stone is soft, common sandpaper will work...just be prepared to go through a lot because it clogs up quick.


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## Tinstaafl (Jan 6, 2008)

And this is going to be done for free?


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## shadysprings (Mar 28, 2009)

stonecutter said:


> I do a lot of custom on-site fabrication with all kinds of stone including making and profiling pool coping. The biggest challenge you will have with a milling machine like that MK is that the surface and the edge of the stone will prevent the guide from sliding smoothly along as you work it...this will effect the profile. A hand held angle grinder was mentioned but you want one that is wet feed and variable speed..this will keep you from burning up an expensive profilerbit . Alpha,makita and metebo some very good brands. Alpha makes a profiler called a "B" type with different sizes for round-over or bullnose and are priced accordingly. They travel along the top of the stone with a nylon guide and grind into the edge. Since the guide only rests on a small portion of the stone it is less of a problem than a full guide set-up. If you need to you can touch up the profile with a diamond cup grinder..but be extremely cautious and only use one that is fine grain to avoid overshaping. You wil have to polish or sand the edge after you profile because the grind with be lighter than the rest of the stone..similar to what happens whe you chisel or cut stone. Hand diamond pads work well for finishing or if the stone is soft, common sandpaper will work...just be prepared to go through a lot because it clogs up quick.


Thanks for the info. I'm first going to see if I can use a $2.50 4" masonry grinding wheel to smoothen corner. If that doesn't work, then I'll move to the diamond cup grinder. If that doesn't work, I'll probably give up. Try it this weekend.


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## shadysprings (Mar 28, 2009)

Tinstaafl said:


> And this is going to be done for free?


Like always, it's never as easy as it sounds. I'll invest about $100 in this before calling it quits.


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## stonecutter (May 13, 2010)

shadysprings said:


> Like always, it's never as easy as it sounds. I'll invest about $100 in this before calling it quits.


I dont know if you considered the fact that if you ruin the coping, its going to be a considerable headache for you to replace it...not to mention cost. I`m not saying you havent thought this through, after all these may be great customers and you want to build or keep a good relationship. 

If you tackle this job, do yourself and the customer a big favor. Get the right tools! If you have no need after the job is over put the stuff on ebay or craigs list...a guy like me will snatch it up. If you still dont want to go with the method described (about $400) then I have another technique. 

Get a continuous rim diamond blade for your circular saw (wormdrive is best) you can get 7" blades at any big box store for $20-$30 dollars. Then get a 10'-12' 2" x 10'. Pre-cut some wooden wedges or buy some that you will place under the board on the poolside...this will give you an angle . I would screw them into the board and make sure the screw is recessed and the point is still in the wood so it doesnt interfere with the guide as you cut. Lay the board along side the coping..this is for your saw to travel on while you cut and will greatly improve control. Keep your blade down at full depth because the lippage or bumps on the stone will prevent the board from sitting level. If you have excessive wobble in the board use a wood shim or wedge to keep it more stable as you cut. Then just finish your cut by sanding.if the stone is difficult you can use a file to prefinish by rounding out he cut...Depending on your angle, this method can produce a 3/8"- 3/4" roundover edge. Air on the smaller side because that coping doesnt look like it is more than 1 1/2".

Do not try to freehand grind stone if you have never done it before..its not rocket science but why risk ruining the coping? If you go with this new way it will cost you less than $100 dollars...Make the customer aware that no matter what way you do it, the pool is going to get dust and stone chips in it.


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## JBM (Mar 31, 2011)

I would pass on it. Tell the customer the best way to do it is to A: Order new stone with a bullnose, B: Remove the stone and send it out to be fabricated.

If you go at it with a grinder it will come out horrible.


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## stonecutter (May 13, 2010)

JBM said:


> I would pass on it. Tell the customer the best way to do it is to A: Order new stone with a bullnose, B: Remove the stone and send it out to be fabricated.
> 
> If you go at it with a grinder it will come out horrible.


 A)This sure would be easier but its probably not an option if they are asking him to shape the existing stone.

B) Unless the coping is poorly bonded you probably would not be able to remove more than 50% of the coping successfully. Even if you could, the cost would not make it worth doing...especially if you send it out to a shop for edge treatment...this option would cost the most.

If he is careful and doesnt freehand the grind, the methods described will work and look good. 

Shady-pass on it like JB says if you are not confident enough to do the job right..it will save you from an expensive lesson.


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## shadysprings (Mar 28, 2009)

Thanks guys. I'm glad I asked for help here because I'm going to think twice before doing this now.
Taking all the stone off is no an option because I'd have to demo and try to save each piece.
So I may try out a small piece where it's not noticeable first. 

I'll keep you all posted. Thanks for the feedback!


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## shadysprings (Mar 28, 2009)

Thanks for all the suggestions. After thinking it through, I ended up just going to cheap and easy way. I would have loved to finish the edge with a nice polished bullnose using the diamond full nose bit or profiler bit, but I don't know how. Small problem.

But here's what I ended up doing-


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## Tinstaafl (Jan 6, 2008)

That's a much smaller radius than we were envisioning. But if that makes the HO happy, good job. :thumbsup:


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## JBM (Mar 31, 2011)

LOL thats all you wanted to do!!


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## shadysprings (Mar 28, 2009)

JBM said:


> LOL thats all you wanted to do!!


Would have preferred to do a full polished bullnose but this was almost free and took an hour to do.


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## JBM (Mar 31, 2011)

Good job though just taking off that sharp edge. It surprised me to see it like that in the first place.


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## shadysprings (Mar 28, 2009)

Masonry work is tough. I'll stick to high voltage wires


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## stonecutter (May 13, 2010)

LMAO....I guess I made a big deal out of nothing!! At least you have some information if your next customer wants you to fabricate some coping!! :laughing:


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