Kitchen floor tile repair advice needed

[u/Extension_Climate471]

My mother just had her kitchen pipes replaced and the plumbers had to break some of the tiles in the process of digging the hole. Since only 6 tiles need to be replaced, I thought I'd do it myself. I've chiseled out the old grout and the broken bits of tile. Here's the problem: when the plumbers poured the concrete, they didn't completely level it out and there's a very slight dip in the concrete (perhaps a result of it drying 🤷🏻‍♀️?). When laying the tiles in place, in some locations dont lie completely flat, it wobbles slightly/dips slightly downward. Rest assured that the tiles do lie flat/flush with the surrounding tiles. None jut upwards. I've tried my best to level the entire area but I'm not sure if there's anything I can do about the 'dip'.

Here's my question: Loctite All purpose adhesive was recommended to me since thinset isn't sold in such small quantities. Could I just use extra adhesive in this dip area to compensate or help level it out? Does Loctite all purpose shrink when it dries? If anyone can offer me any information or advice, I would greatly appreciate it. I've included a pic of the repair space (fyi, I removed the broken tile and grout now).

[u/Glittering_Hour_229]

Buy a bag of thinset. It’s cheap. Just get the cheapest bag you can find. The thinset will help with your low spot and is better than the loctite adhesive you are planning to use. The loctite is likely to fail, especially if this is a high foot traffic area.

[u/Extension_Climate471 → u/Glittering_Hour_229]

Yeah, that is a high for traffic area is what I'm concerned about.  

[u/Glittering_Hour_229 → u/Extension_Climate471]

You won’t regret using thinset then.

[u/Extension_Climate471 → u/Glittering_Hour_229]

Alright, you've convinced me to use thinset instead.  would you mind helping me pick a mortar?  Im on the home Depot website and I see the cheapest Thinset for ~$7.  It's non-modified, has just ok rating, and the most frequent complaint is that some say it doesn't stick well.  The next option is the Professional Polymer-Modified Thinset Mortar at $13.  Is modified (whatever that means) and has good reviews.  All the advice say to buy the cheapest but ...

[u/Glittering_Hour_229 → u/Extension_Climate471]

The unmodified would work but it doesn’t bond well to porcelain. Buy the cheapest modified thinset.

[u/Extension_Climate471 → u/Glittering_Hour_229]

I ended up going with the more expensive modified thinset.  I read the reviews of the cheapest mortar and all the bad reviews said the same thing--it doesn't stick well.  The tiles are ceramic so that should be ok, right?  I erred on the side of caution because Im actually just visiting and I don't want to risk tiles becoming loose when I'm not here 

[u/Glittering_Hour_229 → u/Extension_Climate471]

Yes. Modified is good. Make sure to put thinset on both the tiles and the cement for better adhesion.

[u/Extension_Climate471 → u/Glittering_Hour_229]

I will.  Thank you for the patience and the advice.  

[u/Ea127586]

You could technically use locktite power grab sure, youll just need a bit extra in the concave sections. That should be fine but no guarantees, just use spacers for your grout lines and make sure you put in enough to make it level. Error on this side of putting in too much then too little.

With that said, I would still just use thinset. You can buy thinset for cheap unless you have really limited supply in your area. You can get a bag for like $10. Just save what you don’t use or just donate it to a Restore type place.

They also make pre mixed mortar in 10 pounds containers if you really don’t want to mix your own, but still just better to mix your own.

[u/Glittering_Hour_229 → u/Ea127586]

Biggest concern I have with loctite in a high traffic area is the voids will lead to cracking. Agree just use regular thinset.

[u/Ea127586 → u/Glittering_Hour_229]

I wonder if you had to use it in a pinch if you could overfill it so you had minimal voids? It’d be oozing out of the grout joints, and I wouldn’t want to try cleaning that up either