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high-quality sealer for bottoms of pots?

updated wed 24 jul 02


Anne K. Wellings on mon 22 jul 02

On Mon, 22 Jul 2002 21:30:13 EDT writes:
> Anne, in the Clayart archives, back in Feb., you replied to a post
> about
> vitrifed claybodies, you wrote :
> << I use a high-quality sealer on the bottoms of pots intended to
> hold liquid
> or go
> in the microwave.>>
> I just found out that nearly ALL my cone 6 & 10 pots and vases I
> made of a
> certain claybody, for a couple of craft shows are seeping even
> though, like
> your pots, the glaze does not look crazed!
> To salvage these (since there is about 30 pieces) instead of tossing
> them all
> out, can you tell me what sealer you use and where you get it from?
> I hate the thought of all the pots I sold already that I assured
> people were
> watertight. Ugh!
> Thanks for any help.
> Imzadi

Yes, I'm glad you asked, as I've been wanting to share this information.
The sealer I use is called Lifeguard Concrete and Masonry Sealer and is
somewhat hard to find. I used to get it at Homebase, but the store here
closed, and now I hear it is available at Hardel's here in Olympia, WA.
(The gallon I bought earlier seems to be lasting forever.)

Here is what I got from a search on the company; they can tell you where
to get it in your area.
Lifeguard Waterproofing, Inc.
Cameron J. Mulford,
Tel: 714-712-7383,
Email :
Showcasing its Lifeguard Waterproofing Sealant, a penetrating sealer
based with RTV rubber that has a 30-year warranty. Room temperature
vulcanizing (RTV) is the key to the sealantís durability in waterproofing
concrete slabs, masonry walls, landscaping stone and other porous
I spoke to the guy on the phone and he told me it is heat safe to 400 F.
and food safe after curing for about a month. He was easy to talk to, and
thought my use of the product was suitable.
I like the product because it forms a good seal from the bottom of the
pot only. The clay still looks and feels exactly like clay, maybe a tad
smoother, but when you run water over it, it beads up dramatically. Using
the Giffin Grip, applying it to pots with a brush is a snap.
The drawbacks are that it has strong fumes and is not water soluble so
must be cleaned up with mineral spirits. You need good ventilation in the
room, maybe wear a respirator.
I have also known people to use Thompson's Water Seal on the bottoms of
pots. I have tried Easy Seal and didn't think it worked well.
I think it is very common for people to think their pots are vitrified
and their glazes are watertight, and to find out it's not the case. I'm
sure I have sold seeping pots without knowing it. Of course, it would be
best to solve the technical clay, glaze, and firing problems that are
causing this, but that's not always practical when you've got an
immediate demand for your pots as they are and don't have time to make
Good luck!