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birdbath - to seal or not to seal

Posted by wishdish (My Page) on
Fri, Mar 27, 09 at 11:32

I have a birdbath that I believe is cast colored terracotta. It has that familiar terracotta sound when I tap on it and it has a design on it, so I know it was cast in a mold. It also is a light cream color and the color goes all the way through. So, I'm ready to start glueing stuff on, but don't know if I should do something to it first (after a good cleaning of course). I read that you can glue right on it, that porous is a good thing. But then I read that some people seal terracotta first before attaching shards. I do know not to use Weldbond. Or, I guess I could cover it with a thin coat of thinset. So, what should I do? Of course, I want to get to the fun part and am hoping it's okay to just go ahead and start attaching. I'll be using thinset for that.


Follow-Up Postings:

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RE: birdbath - to seal or not to seal

Here is a very good instruction to sealing terrcottaa frined did in another four..
MOSAIC TERRA COTTA FLOWER POTS

Make sure to clean off any dust from your terracotta pot.

Supplies and Tools:
Terracotta pot,
Oil base primer
Paint brush
Tesserae of your choice for your design
Thin set
Plastic palette knife
Plastic mixing bowls
Grout
Sealer
Handy tools: pool noodles, soft cloth, dental pick

Terracotta should be sealed with a oil based primer.
I use Behr primer sealer. Make sure to seal both the
inside and out side of your pot, and dont forget to get the drainage hole. Allow to dry 24 hours.

Its very important to seal your terracotta properly!

Prepare your glass pieces/tiles for the design you want to create on your terracotta pot.

You want to make sure that you are using a waterproof adhesive for attaching your design to your terracotta pot.

Adhesive you might want to use are a silicone, or thinnest.

I prefer thin set; its a cement-based adhesive. It can be mixed with water, or you can use a liquid admixture admixture is latex or polymer additive in liquid form that gives added flexibility. Some thin set already has a polymer or latex additive already mix in. Check your label and read your instructions.

Some thin set tips mix in a small plastic cup to the consistency of cake frosting. Allow thin set to slake for 10 minutes before you start working to allow the chemical reaction to take effect.

Make sure to mix it from the bottom so no dry bits are left
behind. Make small batches at a time. Thin set sets in about 20 min.
Once thin set is mixed dont add any more powder or
liquid.this is called re-tempering and will break down the chemical process, causing the thin set to be weaker.
If it starts to get too thick to use, throw it away and mix more.
Allow thin set to slake for 10 minutes
Thin set takes some getting use to for spreading; using a trowel shaped plastic palette knife is a handy tool.

And please remember thin set is a cement, and does have a memory. If a tesserae has been in place for 10 min, dont bump it or move it. If you do, put a bit of fresh thin set down.
The cement remembers the old position and will not grip nearly as well.
If the thin set has squished over the top of your tesserae, make sure to clean it off before it dries; its very difficult to remove once it hardens.

Now that your design is adhere to your terra cotta pot, youre ready to grout.

Mix your grout remember to let it slake for 5 min before you apply it to your project. Your mix should be cookie dough mixture. Dont have your grout really thin and soupy.

Working with rubber gloves cover your project with your grout, making sure you push it into the spaces between your tesserae. Allow to sit till you see the grout starting to dry.

I use a dry grout method of cleaning up.
When your piece is ready to clean up, sprinkle a bit of dry grout on your project.

Take a small pool noodle or a soft cloth, clean off all the excess grout on your project. Once you have it all cleaned off and youve inspected it and made sure your lines are all cleaned leave for 24 hours.

Your last step is cleaning off any haze that was left from the first cleaning. Use white vinegar for this last cleaning,
Dont be in a hurry to seal your project, allow your terracotta pot to dry completely.


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RE: birdbath - to seal or not to seal

Although I have never used this particular sealer, I highly reccomend sealing. I always just used a terra cotta sealer.
Not sure which one, but I got them at Home Depot.
I just checked the garage and I don't have any at the moment to get the name, sorry.
Looking forward to seeing your work.


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RE: birdbath - to seal or not to seal

Oh, I have to respond to this post, even though I'm so tired from an all-day trip. DO NOT seal w/an oil-based primer. Oil and water don't mix. Experience here. Not necessary to seal terra cotta b/f using thinset. Read the directions on your thinset pkg. I use Mapei UltraFlex II, and it plainly says that it does not work w/oil-based products. Sorry, NANA. I don't know what instructions you're quoting, but I had a real failure using an oil-based sealer w/thinset. That AND using Weldbond as a sealer for an outside project have been my only failures for outside projects.


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RE: birdbath - to seal or not to seal

Thanks for the replies. If I do choose to seal (might not since I'm using thinset), what do y'all think about Thompson's Water Seal? I think I might actually have some of that in the garage!


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RE: birdbath - to seal or not to seal

NO! DO NOT USE THOMPSON'S WATER SEAL! There is a chemical in it also that loosens the hold of the thinset. This may not happen initially but it will happen. The only outside failures I have had is using Thompson's. Get TileLab Sealer and do as Slow says and thinset right on your substrate, grout and then seal..That's all it will take. Nana, I can't agree with the oil based primer either as I think it would react with the thinset also.
Good luck on your birdbath....post pics.


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RE: birdbath - to seal or not to seal

I am so glad you guys got in here. I couldn't remember about the sealer!
I thought someone had warned me against oil based sealers!
Whew, another project saved!
Now maybe I won't forget next time and can offer some advise!
You got all the best advise Wish......get started, we are waiting............


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RE: birdbath - to seal or not to seal

Thanks. I'm just going to go ahead and start attaching with the thinset - right onto the birdbath and seal with the tile lab after. That's what I do with my stepping stones and they're holding up great, but they're concrete. I was hoping I could just go without pre-sealing the terracotta as well. So I'm happy. Gonna get started tomorrow!


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