# Home maintenance question II: Sealing a crack in a china mug

**URL:** <https://boards.straightdope.com/t/home-maintenance-question-ii-sealing-a-crack-in-a-china-mug/369242>\
**Category:** Factual Questions\
**Created:** [August 18, 2006, 4:25pm UTC](https://boards.straightdope.com/t/home-maintenance-question-ii-sealing-a-crack-in-a-china-mug/369242 "2006-08-18T16:25:36Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![matt\_mcl](https://avatars.discourse-cdn.com/v4/letter/m/7ab992/32.png) [@matt\_mcl](https://boards.straightdope.com/u/matt_mcl)\
**Post date:** [August 18, 2006, 4:25pm UTC](https://boards.straightdope.com/t/home-maintenance-question-ii-sealing-a-crack-in-a-china-mug/369242/1 "2006-08-18T16:25:36Z")

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I think I have this crazy-gluing-broken-mugs-back-together fairly down pat, but I have here a favourite bone china mug (from the British Museum, depicting the Rosetta Stone, if you’re curious) which has somehow managed to develop a crack while remaining in one piece. It’s now starting to discolour on the outer side from coffee, etc. How should I go about sealing it?

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**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\
**Post date:** [August 18, 2006, 5:24pm UTC](https://boards.straightdope.com/t/home-maintenance-question-ii-sealing-a-crack-in-a-china-mug/369242/2 "2006-08-18T17:24:07Z")

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You really can’t.

If you had ceramic glaze and a kiln, you could try overglazing the whole mug and firing it, but that would likely only end in heartbrake as you probably didn’t use a glue that’s heatproof.

Best thing to do is call the darkening around the crack character, or evidence of an honest life, don’t use it for coffee and simply display it.

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [August 18, 2006, 5:33pm UTC](https://boards.straightdope.com/t/home-maintenance-question-ii-sealing-a-crack-in-a-china-mug/369242/3 "2006-08-18T17:33:19Z")

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[QUOTE=gotpasswords]  
You really can’t.  
[/QUOTE]  
Well, you can break it along the crack on purpose, and then crazy-glue it back together. That should stop the seepage. I’ve done this a couple times and despite how wrong it seems, it has worked.

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**Author:** ![constanze](https://avatars.discourse-cdn.com/v4/letter/c/f9ae1b/32.png) [@constanze](https://boards.straightdope.com/u/constanze)\
**Post date:** [August 18, 2006, 10:17pm UTC](https://boards.straightdope.com/t/home-maintenance-question-ii-sealing-a-crack-in-a-china-mug/369242/4 "2006-08-18T22:17:32Z")

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I’ve always heard (but not yet needed to try it out) that if a plate of china or similar has a crack, you put it in pot full of milk (I guess natural milk, but they don’t specify), and gently cook (not boil) it for half an hour to an hour, and somehow, the crack will have sealed.

Obviously, this won’t work for large cracks, and I don’t know if your mug is too different from “normal” china plates…