Different types of fast setting mortar. Mapei Ultraflex RS.

[916tile]

Does anyone know the chemical that is used in Mapei Ultraflex RS "fast setting"? Its a dream to work with. Like 1-2 hours of pot life but when it kicks it goes off and dries completely almost instantly.
Customs Speedslope mortar has the same chemical, you can tell because the mortar will dry its lighter color and it gives off heat as it cures. You can put your hand on it and feel the heat, and it gives off a faint sulfur like smell.
These two products differ from customs speed set and other typical fast set tile mortars that start to harden up in the bucket quickly, but do not attain a full cure (dry mortar color) for hours afterward. They also do not give off heat as they cure like the Mapei does.
I'm almost positive they are using different chemicals to harden.

[Kman]

I used some a few weeks ago to set in a bathroom in an area in front of the vanities so they could be used the same night. I didn't notice anything different from the others that I've used, although I don't use them on a regular basis, just on certain occasions.

I did notice that it set up in about 2 - 2 1/2 hours, and that was 8x40 tiles over Stratamat (StrataHeat mat, to be specific). I did what I normally do with speed set, which is to dry-fit every piece, then set aside enough pieces to get back into the room and set everything while I work my way back out. It was certainly workable until then end, but I noticed that when I was setting my last few pieces, it wasn't the same consistency when I started. That was over a period of about 45-60 minutes.

If I ever wanted to extend the pot life of rapid set, I would mix in some regular mortar. Mix it dry, then add water and mix again. I could easily get two hours out of it, it just wouldn't set quite as fast, maybe in four hours or so.

[tilemanct]

If you want to try a interesting rapid Thin set try Ardex X32. Thin bed or medium bed. I know what your saying with the Mapei RS. Wait, wait, wait then done!

[MAPEI - Technical Service]

Good morning Isaac!

The chemists are careful what info they give us Tech folks regarding some of the magic we put in our products, so here's what I know:

In our rapid-setting cement products, we use calcium-aluminate cements which cure much faster than traditional portland cement-based products, and give off heat when they do so.
I can't really speak to what the competition uses, or if there are any other additives we may put in ours to speed things up, but R&D has told me the type of cement is the big difference.
Yes, there absolutely is a 'point of no return' when the product goes from pliable to 'uh-oh my margin trowel is stuck in the bucket', but I don't have the scientific answer on why exactly it happens that way.

I hope that helps!

[916tile]

Originally Posted by MAPEI

In our rapid-setting cement products, we use calcium-aluminate cements which cure much faster than traditional portland cement-based products, and give off heat when they do so.

Thank you! That was the answer I was looking for. We recently did a 7000 sf project in Tiburon, which sits on the edge of the San Franciso Bay (very high humidity and cool temperatures). We started out with Merkrete 720 RS, but after 2 days of fighting very short pot life (like 20 mins max before the mud was unusable) and never fully curing after several days, we switched to the Mapei and it was a dream. Like I said, plenty of pot life and then when it kicks, it goes hard. We needed this because we were using leveling clips (8x48 planks), and with the Merkrete, even after 24 Hrs, the tiles were springing back and breaking bond after we popped the Raymondi wedges.
Ever since then we have stocked a pallet of it, and my guys love it. I have never been a Mapei guy, but I am definitely sold on this product and will probably be trying out more of your products.
Also, will you be at coverings? Would like to meet up if you are.

[MAPEI - Technical Service]

Glad to hear that was the info you needed Isaac!
Just remember the great pot life you're getting now when summer rolls around... The hotter the powder, water, or environment is, the quicker these rapid-sets go off!

No I wont be at Coverings this year; I did Surfaces in January, and since Coverings is close enough to MAPEI HQ, the local boys will be handling it this year. I try to make all the shows I can and that I can justify to the Travel Dept. though, so I'll catch you at the next one!

[eurob]

The rapid set mortars -- UFRS -- also work great -- fast setting and cure -- when the production date vs. Installation is in the 1 to 2 month period. The further it gets from the production date , the slower the setting

Ardex X7R is also a great product to use.

[tilemanct]

Isaac
I'm more troubled hearing the "tiles were springing back and breaking bond" more than anything else. How badly bowed were these tiles? Was the substrate so out of spec(1/8" in 10") that you were literally fighting the tiles to lay flat. Leveling clips are great but they cant make up for the "ski camber" of poorly made tiles.

[jadnashua]

In one class, they indicated that other than the specific type of cement used, most of them have some sort of inhibitor in the mix to give it a better pot life. The proportion of that will also affect how fast one kicks off. IOW, most mortars would be faster if they didn't have an inhibitor in the mix.

[916tile]

Originally Posted by tilemanct

Isaac
I'm more troubled hearing the "tiles were springing back and breaking bond" more than anything else. How badly bowed were these tiles? Was the substrate so out of spec(1/8" in 10") that you were literally fighting the tiles to lay flat. Leveling clips are great but they cant make up for the "ski camber" of poorly made tiles.

They were 8x48 Emser Legacy (Italian). Nice porcelain but definitely had a bow in them.