Anyone know what these marks are on marble tile left by the spacers?

[jeffreythomas]

I'm installing marble tile and everywhere there was a spacer there's marks left. The marks are dark half circles on each tile, I'm pointing to a set with the spacer. It's been 3-4 days, I put a fan on it thinking it was wet, still there. I read that acidity can react with the marble and leave water marks? The spacers were left in some places max day and half. It does seem less of a mark the quicker I removed the spacers. The spacers are the flexible kind. I tried light scrubbing. I also still have some tiling to do, are the hard spacers less likely to do this? Not sure why the pictures rotated once I uploaded them. I friend recommended a stone cleaner, said that maybe the oil in the spacer leeched in.

[dgbldr]

Jeff, are you a professional tile installer or homeowner/DIYer?

[jeffreythomas]

I worked on tiling crews when I was younger. I mostly do carpentry, but have done several tile jobs in the past few years. I do home renovations. I was working with someone more experienced as well on this project. I used large format/stone white thinset. Why do you ask?

[jeffreythomas]

Also the project is my own shower, I got the tiles on craiglist and I'm fine with the little chips.

[dgbldr]

I asked because I don't know the extent of your knowledge and experience.

If that is real marble, did you seal it prior to installing? What sealer did you use? Do you have the manufacturer's instructions? Do they require sealing with a specific product before installation? In my experience, they typically require using a "porous" type sealer with marble.

[jeffreythomas]

Yes, it is real marble. I haven' t worked with it before this. Everything I read says to seal it before grouting, but not before installing.

[dgbldr]

Look at the manufacturer's instructions. Very likely they require sealing prior to install. Most do. Marble is very porous so very easy to absorb stains, even some thinset can stain it. Very likely something from the spacers leached into the marble.

[jeffreythomas]

Thanks for the response. I got them from somebody off craiglists, no manufacturer information. It seems debated upon whether to seal before or after install. Which install can mean just thin set, or thin set and grouting. Someone did bring up a point that sealing it could effect the ability of the thin set to grab the tile. It does appear to be more generally agreed to seal before grouting though. I bought some hard white spacers to finish, the previous were blue soft ones. I think that should help prevent more marks. My biggest concern now is removing the existing marks. I'm trying some home remedies I have been reseaching. I made a polstice out of diluted hydrogen peroxide and baking soda, applied to a little area out of sight. I found some products that seems similar to that but specifically made for it, like Mangia Macchia. It removes oil stains, by leeching them out as it dries, then you scrape it off. Hopefully it works!