As I understand it: Thinset, a portland cement product,
IS a mortar. Mortar being something that sticks things together.

Thinset is a cement-based mortar - some with and some without polymer or laytex admixtures. I use it for all outside mosaic adhesives and grout, except when I'm in a GE II mood for adhesive. I use Quickcrete brand waterproofer - a water-based sealer for masonry etc. - that is when I'm not too anxios to start gluing and remember to seal.

OK, thanks! I thought I was right about both of those things but I was starting to doubt myself!! Ever have one of those days??

The more I think I learn the less I think I really know!!!

Same here. I also think I better go find that receipt, got something I do believe needs to be returned. I kept hearing everyone talk about sealer and I've not been sealing anything. So...I go to Lowes and buy grout sealer, don't think that is what you all have been talking about huh!!!

lilym,
No, you're right. Grout sealer, stone sealer etc.

I'll warn you and then let you fly like we all have to . . . .

Terra cotta soaks up and holds water like a sponge. Unless every teeny weeny square inch of the pot is sealed tight it will expand and contract and grout and tesserae go flying off at an alarming rate . . . .

Fly!

Allright, So I guess I'd better go with a glazed pot, my original plan. See, I learn so much from you gals!!

Guess it depends on the climate. The huge Mexican pot I mosaiced by the swing patio I completely forgot to seal it inside and just didn't seal the outside. Didn't remember that inside sealing stuff until I got it planted w/a dwarf Gardenia. I was soooooooo afraid over the winter cuz we had freezes, but it didn't crack. That's not to say it won't, I know, but it's ok so far. If it does, I'll take the dirt out, put it back together w/mortar, mosaic over the seam and SEAL that sucker. The large pot I had on top of the blue pedestal wasn't sealed either. I DID empty it for the winter, but left it outside. The one behind the blue pedestal I used the Quickcrete waterproofer, and I left it planted all winter. The reason these are holding must be the climate here. I know there's a possibility of cracking, and I'm gonna TRY to remember to seal if I should do anymore clay pots. I have sealed a birdbath TBM.

Glasshappy, I have made several birdbaths from terra cotta trays. Here is what I've done:
- I seal it first with diluted Weldbond all over.
- Then I paint the bottom of the tray with white acrylic paint - and this is basically to provide a base color for glass.
- After it's mosaiced and grouted, wait for a few days then I seal it with H&C concrete sealer.

I have not had any problems at all with this process. I live in North Florida where we have a few nights of freezing temperatures, and lots of heat and humidity the rest of the year.

Ok, what I bought is Aqua Mix Grout Sealer. The salesman said it's purpose is just to keep the grout from getting dirty and/or stained and had nothing to do with keeping water out etc..
The bottle just says:
Repels Food, Dirt & Grease
Interior or Exterior Use.
I figure I'll use it on the table for sure.

I'm like Slow I've never sealed any of my terracotta and they have been out in the weather year round but we don't freeze only Heatttttttttt....but I think I'll start sealing just for safety sake Annie

I don't seal my terra cotta either. I've got pots out there that have been in the yard six+ years. Maybe being in Florida where the temps don't plunge to freezing is the reason mine have been fine. I do seal the grout tho and it does bead the water some.

p

LIL: That's what I've been telling y'all, so finally just quit. Sealing grout is ONLY to make the grout stain resistant, NOT waterproof it. And even at that, for example on kitchen counters, it should be done every year. NOT in this house! I spritz on bleach for that purpose, but that's why I don't seal my work afterwards. The mortar I use is impervious to sealer anyway - not necessary.

Okie dokie.