Terra Cotta Pot – Decorative Paint Project Question
What Is The Best Method To Seal Off The Interior
Of A Terra Cotta Pot?
I received an email from Leslie asking:
This is a fantastic website, extremely helpful. I have found the articles in the Decorative Paint Techniques category very informative. THANKS!
My question: I am using gauze fabric and modpodge and then painting over it with airbrush metallic paint on the outside of the terra cotta clay pot. Any ideas what to use to seal the inside of my pot, so that when dirt goes in and the pot is watered, it won’t effect the outside of the pot?
Thanks so much. Leslie
My reply:
Hi Leslie:
Thanks for the compliments, I really appreciate you taking the time to tell me. 
About sealing the inside of a terra cotta pot, there are two ways you can approach this:
#1) Apply a number of coats of an acrylic or latex paint to seal off the inside. (Easier for brush clean-up than oil-base paint.) You can also use a clear spray, like Krylon acrylic. Or, try a polyurethane. Anything, basically, will “seal off” the interior.
#2) The “safest” route to really make double-sure that whatever you’ve applied and/or painted on the exterior of the pot won’t be affected is to use a plastic inner pot to plant in.
I’ve never had a problem with the exterior paint bubbling or flaking off of terra cotta pots, as I do always liberally spray about 3-coats of Krylon onto the interiors … but then again, I haven’t ever used fabric and modpodge on the outsides.
If I were you, I’d make sure to apply a generous base coat of paint on the outside of the pot, too. Unless that would keep your fabric and glue from sticking properly?? That base coat on the outside will also act as a moisture barrier.
If you do use a brush-on paint or spray paint for the interior of the terra cotta pot, I’d make sure to cover all the surfaces extremely well.
Does this help??
Sounds like a fun project. Good luck!
Leslie wrote back:
Dear Claudia: Thanks so much for getting back to me. Your information was wonderful and very helpful!!! I’ll definitely try that technique on the pots. I’m going to do some experiments first to see just how they do outside. I’ll do this before I decide to sell them, so my clients won’t have any problems. All the best, Leslie
My reply:
You’re welcome. Like I said, an inner plastic pot that actually holds the dirt and plant would be the very best bet to increase the longevity of your artistic applications!
And providing a plastic inner pot would let you off the hook “legally” if you are selling your pots … meaning you clearly state on a little label that your embellished terra cotta pots are NOT guaranteed to last forever if someone places dirt and a plant directly into them.
If it were me … I would cover myself in that way if selling them retail. You’ve warned them up front and provided the plastic inner pot … no unhappy customers on up the road!
Just my 2-cents. Claudia
April 13th, 2009 at 9:14 pm
I hear that WD40 or 2 in 1 oil is good for sealing terra cotta containers. Do you know if these work? If so, should they be applied to the outside or the inside, or both?
Thanks for any help you can provide.
April 15th, 2009 at 10:34 am
Hi Doug:
In my humble opinion … DO NOT use either product on terra cotta thinking they will “seal” the pots.
In all my years of reading hundreds of posts and forum threads on other reputable sites that pertain to this very subject, I have NEVER seen one mention of someone trying this, or more importantly doing this with success.
If you want to seal a plain terra cotta pot (meaning you won’t be painting a decorative finish on it), then I will suggest using a clear Krylon spray paint, for ease of application. I’ve never ever had trouble using Krylon as a sealant.
Or, you can buy a clear brush-on polyurethane sealant.
I hope this helps.
On a side note: of course you could try testing each product on 2 small pots to see what happens.