Suzannah

[Suzannah]

I will try and let you know thanks

 

[Suzannah]

I don't know, how can I find this out?

 

[user123]

Lime!!! could be!! - remind me, Andrew, is lime acidic or alcaline?

 

[user123]

I don't know, how can I find this out?

When you scratch slate with a nail, you get a white powdery scratch...with granit you'd have trouble scratching it..

 

[SandyFloor]

Lime!!! could be!! - remind me, Andrew, is lime acidic or alcaline?

Alkaline

 

[Suzannah]

yeh it was a white powdery scratch

 

[user123]

thanks Sandy, just checked, too, alkaline it is.... hmmm, don't think it's lime grout then as it would have got cleaned off with the acidic grout cleaner, would you agree? So we have slate, as Susannah did the scratch test, and what? I'd still go for the salt test, Susannah, and then let us know what happens...

 

[enduro]

We used Aqua Mix Phosphoric acid cleaner and it worked very well. Just test a small area overnight, follow instruction carefully. www.tradetiler.co.uk a forum sponsor should have some. This can be used on slate

 

[Suzannah]

tried that it hasn't worked any other ideas?

 

[Suzannah]

the salt i meant not the Aqua Mix Phosphoric acid cleaner

 

[Ajax123]

I agree with MG that it is probably acid burn. The HG stuff is made with Phosphoric acid which is pretty strong. It looks to me like you have either taken off a "film" of something that was on the tiles or you have taken off the original dressed finish as the areas that are grey look like natural blue slate colour (which is a light grey).

Whilst I sort of agree with the salt theory I think a simple strearate based cleaner and a good old fashioned scrubbing brush might also do the tirck (i.e. soap and hot water).

Have you cleansed the whole slate or just the edges? Did you dilute the cleaner.

I did this with an old quarry tiled floor may years ago and a similar thing happened i.e.the edges stayed white and discoloured. I used to work in the food industry where the cleaning guys used mechanical scrubbers (like the old fashioned school caretaker) which I ended up using and after a couple of passes and lots of rinsing it came up a treat.

Remember it's an old floor so it is worth working on.

 

[user123]

Ok, rewind... after what Ajax said.. yes,the acid does worry me really... as it is the acid you put in the first place that caused this... I will think some more... it's a beautiful floor and the point with the elbow grease and soap (alkaline) is a valid one... hmmm...

 

[The Legend; Phil Hobson RIP]

This is a very interesting post, I am intrigued:welcome:

 

[Suzannah]

Hi, yeh I just cleansed the edges and yes I diluted it but not as much as I should have!
Ok I will spend all tomorrow scrubbing and let you know how I get on Thanks

 

[Ajax123]

sorry it took me a while to type it .........

the HG grout cleaner is made with phosphoric acid