bad marks on stone

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bad marks on stone

Discuss bad marks on stone in the Australia Tiling Forum area at TilersForums.com.

J

jonnyc

just started a new job with a mandarin stone 500x random .
cant remember the name .
Darren ( freeze) do you recognise this one.Ive been put on their recommended list for weybridge!!!
stone beautifully cut square and even thickness.
client received stone a month ago and brought in to house and stacked the tiles slightly offset on top each other so that they were easy to pick up.
when bringing stone in to area to be tiled can see that the parts of the tiles that were exposed to air and sunlight have changed colour.
this is clearly visible on photos.
any ideas about how to get rid of these marks or what causes them
having flagged them up i have been asked to fix regardless in the belief of client that what was hidden from light / air will change colour when exposed and fixed .
i ve thrown the whole innards of cleaners in my van and wont touch it 2014-04-18 12.30.07.jpg 2014-04-18 12.30.31.jpg 2014-04-18 12.29.38.jpg nd wont touch it
 
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C

Concrete guy

jonnyc said:
Sorry don't understand
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Assuming no one has done anything dumb here like presealing and stacking.

The exposed bits have dried at a different rate to the non exposed bits.

Don't mess around with chemicals, it won't make a blind bit of difference.

Stick a tile in an airing cupboard for a day or two and see if its appearance changes.
 
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J

jonnyc

You will notice that the edges that were exposed are darker than the parts of stone that were covered.you would expect this to be reverse way round.if there were any moisture in stone it would be in the middle sections .put a hair dryer on the stones makes no difference .
tried wexa,wax off ,outdoor cleaner and oxy clean crystals but none work.ii have had this before when exposed edges of tiles in a crate are left outside.
always seems to happen with grey stones.something to do with oxidation?
 
C

Concrete guy

jonnyc said:
i have had this before when exposed edges of tiles in a crate are left outside.
always seems to happen with grey stones.something to do with oxidation?
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If this is a dense as I think it is, which dark limestones tend to be, a hair dryer wouldn't make any noticeable difference.

Oxidation is possible, if it is that I'm not sure how you'd chemically deal with it. It would probably require re honing. Or as the rest of the stone is exposed for a month it would create the same patina, but then you'd need to leave it unsealed for a month.

Call Mandarin, see if it's known problem with this product.

It almost reminds me of Mexican Saltillo when it was stacked to dry you'd get distinct patches of light and dark, which in that case was UV light bleaching. What you have though is the reverse, which is odd.
 
J

jonnyc

It's called Blenheim by mandarin.i checked stone with damp meter and dry.its lightly brushed so can't be re honed.
had a similar problem with Jura grey few years back when builder covered floor with cordex over building card for whole winter with heating on.it sweated and left brown zebra stripes on floor . Could not get out chemically and had to grind and repolishing whole floor.
client is convinced it will even up but I'm not sure
 
C

Concrete guy

jonnyc said:
Can you re brush just parts of a stone and when Doing so does it take a fraction off the surface.what do you attach the bits to
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I'd be inclined to brush an entire tile rather that part, it would even the process.

Yes it does remove some material, how much material would be dependent on how coarse a brush you use. These are diamond filament brushes available in different grades.

The one pictured above has a captive M14 nut so would fit on any hand held polisher, Flex, Makita etc.
 
C

Concrete guy

jonnyc said:
Sounds like a last resort option .how much do these cost and how many would I need
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It is a last resort option. So let#s hope the customer is right and things sort themselves out.

It's not a stock item for us, we can order them in though.

How many you'd need would be determined by how many tiles you have to refurbish, the degree of brushing you need to match and the size of head required.

Stonegate stock these, this link gives you and idea of costs.

Broken Link Removed
 
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C

Concrete guy

jonnyc said:
It could be this stone.looking at images on google some are very similar.is azul same as mole sons blue
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Azul simply means Blue in Portuguese/Spanish.

Therefore Azul Valverde = Blue Valley.

Azul Moleanos is generally known here as Gascogne Blue.

Valverde and Moleanos are different quarries, both in Portugal. The blue occurs in seams within the beige bedrock, which is often why you can find blue/beige mixed colours.

You get a number of different shade of these products dependent on which quarry/seam it comes from.

I'd generally ignore whatever name Mandarin give it, they tend to make them up rather than use recognised regional names for their stone. It stops people Googling to find the products cheaper elsewhere.

If you do a lot of stone it's not difficult to buy direct.

I used to deal with these people a great deal:-

http://www.airemarmores.pt/

They are actually the quarry owner and producer, so a lot of the smaller producers would be buying blocks from these people to start with. Orders can be from as little as 100m2 and they will organise truck freight for you.

This firm is also very good:- http://www.dimpomar.com/en/ particularly for some of the nice Portuguese marbles from the Estremoz region. Generally a longer lead time though.
 
J

jonnyc

Ats .the stone does vary from blue to grey beige mix.most probably one or the other.doesnt matter that much.what I do find interesting is that I have no one on this forum or another has come across tiles getting brown marking when edges are exposed to sunlight.i have come Across this many times but in every other instance I have never fixed pieces with these marks or cut them off.this is first brine I gave been instructed by client to lay as is.
 
F

Freeze

Sorry John, have not been on, flat out at the moment, have worked the last 16 days straight through so only just seen this post, I have fixed Blenheim a few times, and have seen this problem before but not to this extent, more like picture framing. Had that issue with a showroom floor I did with Blenheim, and was told just to fix it leaving out the really bad pieces, I tried loads of different chemicals but didn't change the appearance at all, I thought at the time it was moisture, and over time it did improve, but was still visible, I wouldn't be happy with fixing that before I had a solution, let me know what Mandarins advice is on it
 
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