What's the best way to seal a cracked toilet tank?

bravenrace wrote: You guys are just making me more determined to find a way to seal the leak. Seriously, its not pressurized, and although i know there is head pressure, still nobody has told me why I can't fix a leak in a ceramic toilet tank.

Because it is basically glass. It is hard to bond to and the different coefficients of thermal expansion make it hard to keep the glue attached. Also because the same expansion and contraction cycle (every flush) tends to make the crack spread.

If I HAD to make such a repair, I would use a urethane epoxy. The stuff is flexible when cured and tough. We use this stuff at work:

http://www.henkelna.com/product-search-1554.htm?nodeid=8797913579521

I would also have a vacuum at one side of the crack and pull the adhesive through to make sure I had full penetration.

Lower the water level in the bowl via the float to under the crack. Problem solved!

You will also save tons of water for the environment, and, you will get the added workouts of plunging incomplete flushes all the time!

KyAllroad wrote:

bravenrace wrote: You guys are just making me more determined to find a way to seal the leak. Seriously, its not pressurized, and although i know there is head pressure, still nobody has told me why I can't fix a leak in a ceramic toilet tank.

Two reasons really. One is that porcelain is a ceramic which is fired in a kiln. Once cracked it will never be exactly the same and while it could theoretically be superglued back together (if you could get the glue to wick completely into the site of fracture), as long as there was ANY flaw or imperfection you are running the above mentioned risk of water damage (theoretically tens of thousands of dollars). All to prove a point and save the $32 it costs to buy a new one. Broken windshield: replace. Cracked brake rotor: replace Broken toilet tank: sorry, I don't want to sound defeatist and I do understand the urge to be able to fix anything but given the risk/reward ratio, replace.

Finally an answer that makes sense. Thank you. The rest of you are just smart asses.

Finally an answer that makes sense. Thank you. The rest of you are just smart asses.

trucke wrote:

Finally an answer that makes sense. Thank you. The rest of you are useless smart asses.

FTFY, er, FTFM, umm, FTFY&M

Toyman01 wrote: Super thin cyanoacralate. It will wick into the crack and seal it. Get the good stuff, not the cheap "super glue."

I have to add that this was a very helpful response, even though it was severely lacking in details. Nevertheless, I'm going to try it after I throw in the towel.. you know, into the tank to dry it.

Standing by for results...

bravenrace wrote:

Toyman01 wrote: Super thin cyanoacralate. It will wick into the crack and seal it. Get the good stuff, not the cheap "super glue."

I have to add that this was a very helpful response, even though it was severely lacking in details. Nevertheless, I'm going to try it after I throw in the towel.. you know, into the tank to dry it.

Sorry for the brief response, I was on my phone at the time.

CA glue. Cyanoacrylate glue is commonly known as super glue. The cheap stuff you get a Walmart sucks. The good stuff is available at hardware stores and hobby shops. They make several thicknesses. Super thin, medium, thick and gel. You want the super thin. It's thinner than water and will wick into the crack. Wick it into the crack until it stops taking it. At that point the crack will be sealed and will be stronger than the porcelain around it.

The best glues used to be made by Bob Smith Industries and available at hobby shops. The thin is in the blue containers.

Don't buy more than you need. It has a shelf life measured in months, even if the container isn't open.

Keep your CA in the shop fridge, next to the beer, for longer shelf life.

Who wants to hear a cracked toilet story??? I got called out to replace a toilet about 12 years ago. It was in one of those old roadside single unit motel/low rent efficiency apartments just off Cape Cod. Renter was a hard core biker guy that lost a leg in a motorcycle accident a couple years prior. Unit was built on a slab and the bathroom was one step down, about a 6" drop. Guy gets up and takes a shower. Goes out into the bedroom/living room area and gets dressed. Goes back into the bathroom to brush his teeth. Instead of taking his crutches, he just hops on one leg. When he hops down into the bathroom, the floor is wet and he slips. Goes head first into the toilet tank smashing it to pieces. Knocks himself out cold and ends up face down bleeding wedged between the bowl and the wall. Water continues to try and fill the tank, but the tank is smashed. Water slowly fills the bathroom up to the level of the living room and eventually spills out under the front door into a common area. Someone busted in the door and found the guy, still alive but unconscious and close to drowning. I got another one about my dad falling down a flight of brick stairs while carrying a toilet. Toilet shatters and severs every tendon in the palm of his hand. Pretty cool seeing fingers pointing at 90* straight up and away from the back of his hand.

tr8todd wrote: Pretty cool seeing fingers pointing at 90* straight up and away from the back of his hand.

You're definition of "pretty cool" must be different from mine. That gives me the heebie jeebies.

In college, my roommate thought it was fun to throw water dynamite in the urinal next to someone that was relieving themself. Usually, the water would just splash on them. One time though, the urinal exploded into several pieces of porcelain and I showed him how to glue it back together with liquid nails. It was ugly, but didn't leak.

Funny thread this.
I'd replace the tank.

I faced this same thing, only my toilets are the non politically correct 3 gallon version so the tanks are NLA. So I used 'Seal All', which is even gasoline proof. Worked like a charm, as it always does. Comes in a yellow tube, it dries clear.

In reply to Curmudgeon:

Thanks! I didn't do anything with it last night for reasons I won't go into, but I found that Autozone has it, so I'll pick some up tonight and try it out. Thanks again, Curmudgeon.

In reply to RossD:

That idea "stinks".

If I had to keep it in service, because I really couldn't afford a new one? Wrap it in duct tape, the whole tank, with good tape. Then it's less likely to eventually explode and get water everywhere, and dump more water from the fill valve, probably when you aren't home

In reply to Kenny_McCormic:

Thanks. That was so helpful.

bravenrace wrote: In reply to RossD: That idea "stinks".

A sprinkle of lime every time

Keeps ths E36 M3ter from getting bitter.

In reply to bravenrace:

Don't get me wrong here, I love the idea of not having to replace it, it's just not practical in this case. The risk of a flood outweighs whatever the tank costs.

In reply to Datsun1500:

In case you haven't noticed, I want to keep my current tank, not buy a new one.

Have you guys really not heard of Goop?

If had this and a roll of duct tape on the Titanic, it would still be sailing.

In reply to Datsun1500:

That's great! Maybe you can have your own thread about that, instead of pretending you know more about my situation than I do.