Questions about thinset mortar.

19 years ago

Some of these questions might seem stupid, but I'd like an answer from those who have used it because I'm about to undertake a project and one of the places I buy my stuff from hires people who don't know a darn thing about the department they work in the store. (They recently hired a friend of mine for the flooring department simply because she answered an 'area' question correctly on a survey. She knows nothing about flooring.)

I know from reading previous posts that it can be used as an adhesive and also be used as a 'grout'and that it does not need to be sealed. If my assumptions on these points are wrong, please let me know.

- Do you simply mix with water or are there other additives which must be mixed in?

- Can you mix small quantities at a time?

- How long before it sets and the pieces are 'glued'?

- How long can you have thinset in a bucket before it is no longer good to use?

- How long before you can place outside to the elements?

- Can you add colouring (water based paint) and if so does this affect the integrity of the product?

- Can this stuff withstand freeze and thaw and be left out in the winter?

My plan is to purchase some stepping stones, glue some porcelain tiles in a fish pattern to them, grout, then place a path around our home symbolizing a school of fish. The main issue here is that taking these stepping stones inside every fall would be out of the question so they would have to remain outside.

Any info would be great!

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Comments (4)

LinLee
19 years ago
Hi Tiffy,
Ok...I'll bite.

- Do you simply mix with water or are there other additives which must be mixed in?
*If you buy a "modified" thinset the additives are already in there...recommended for glass. And yes, you simply mix it with water.
- Can you mix small quantities at a time?
*Yes. You'll add the dry mix to the water, not the water to the dry mix. Usually I'll do about 1/2 cup of water then add 3 to 4 times that amount in dry mix. You'll
want a fairly stiff mix. I'll tip my mixing pot upside down and when it doesn't move I'm done adding dry mix.
You'll then let it slake (just sit there) for 8 to 12 minutes. Th thinset that you buy will tell you the time frame.

- How long before it sets and the pieces are 'glued'?
*That's all dependant on the humidity and the mix. If you're working on a vertical surface I'll usually have some painters blue tape to hold the pieces while I carry on. But after about an hour the tape can be removed however the thinset is not dry. I would wait about 48 hours before any grouting to allow the thinset to cure.

- How long can you have thinset in a bucket before it is no longer good to use?
* Personally, I've found it to set up too much at about the 25 minute mark. Make sure to stir it up often to keep it workable. The thing that you don't want is a dried skin surface.
- How long before you can place outside to the elements?
Once the grout is cured in about 48 hours then sealed (If that's of interest) it's supposed to be ready for the elements. I'd myself give it a week or so to dry before exposing it...but that's just me.

- Can you add colouring (water based paint) and if so does this affect the integrity of the product?
*Sorry...I have no experience in this.

- Can this stuff withstand freeze and thaw and be left out in the winter?
Yes. If the base that you're are using can be left outdoors and you use a thinset and a grout for outdoors than it is perfectly safe.

I hope I haven't confused you even more.
Good luck!
Linlee
pea_
19 years ago
I feel your pain about the answers received from the store, I've caught the salespeople wrong on numerous times.

-I use 2 different thinsets, one is already polymer modified and one isn't. I mix both the same and not had a problem...just water, you could add a polymer additive if you get a nonmodified thinset but I've not found it is neccesary.

I use thinset the day I mix it and in small batches. Thinset once applied to a stone is workable for 1-2 hours at most if mosaic is handle after that your tile will fall off and you will need to apply more thinset. Thinset generally cures in 24-48 hours. I usually then grout mine with grout, wait another 2 days, then seal, wait 24 hours and put where I want outside.

I can't answer your coloring question or the weathering question(I'm in Florida, mine don't freeze.)

p
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chickeemama
19 years ago
tiffy your questions where not stupid, I got answers to questions I didn't even realize I had!!! Thanks girls!!
joyy
19 years ago
there's also rapid set thinset if you're in a rush but it's more expensive than the regular stuff. obviously, it sets up a lot faster so that means less of a window of working time - which means you'd need to make smaller batches of mortar.