bad marks on stone

[Concrete guy]

Sorry don't understand

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.

 

[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?

 

[Concrete guy]

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?

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.

 

[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

 

[Qwerty]

I've had similar happen and in my case it was dust from the builders that had settled on it in a damp atmosphere and almost appeared to etch itself onto the tile. Mine came out with cleaners though, so a bit stumped in your case!

 

[jonnyc]

I've had similar happen and in my case it was dust from the builders that had settled on it in a damp atmosphere and almost appeared to etch itself onto the tile. Mine came out with cleaners though, so a bit stumped in your case!

Could be this .some one else also mentioned tannin.

 

[Concrete guy]

Well lets hope they eventually even out.

They could actually be re brushed. That's what these are for:-

 

[jonnyc]

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

 

[Concrete guy]

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

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.

 

[jonnyc]

Sounds like a last resort option .how much do these cost and how many would I need