# Unexpected Chemical Reaction in Art!

**URL:** <https://boards.straightdope.com/t/unexpected-chemical-reaction-in-art/157422>\
**Category:** Factual Questions\
**Created:** [February 25, 2003, 4:36pm UTC](https://boards.straightdope.com/t/unexpected-chemical-reaction-in-art/157422 "2003-02-25T16:36:19Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\
**Post date:** [February 25, 2003, 4:36pm UTC](https://boards.straightdope.com/t/unexpected-chemical-reaction-in-art/157422/1 "2003-02-25T16:36:19Z")

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My wife is an Early Childhood Educator. For art projects, it is common for her to mix Tempera paints with Elmer’s glue for colored glues. (Of course, now you can buy it, but you can make it yourself.) Anyhow, this time she mixed the paint with an unmarked white glue. Before she knew it, she had created “The Blob”! The mixture started “erupting” in slow motion doubling in volume and overflowing the container. A vinegar-like smell was noted. It is obvious the increase in volume was caused by the escaping gas.

It is suspected the glue was actually a decoupe glue. Does anyone know what happened here? - Jinx

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**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\
**Post date:** [February 25, 2003, 4:43pm UTC](https://boards.straightdope.com/t/unexpected-chemical-reaction-in-art/157422/2 "2003-02-25T16:43:15Z")

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The glue may be decouche glue? decoupe? Tomayto, Tomaahto!  
(I can hear the French already cringing as some silly American slaughters their language! Sorry!) - Jinx

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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:** [February 25, 2003, 5:02pm UTC](https://boards.straightdope.com/t/unexpected-chemical-reaction-in-art/157422/3 "2003-02-25T17:02:46Z")

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A bit of googling reveals many reference to “pH neutral” white glues, which leads me to suspect that some white glues are acidic. From the odor you mention, the culprit is probably acetic acid. Some [tempera-like paints contain calcium carbonate](http://www.sewanee.edu/chem/Chem&Art/Detail_Pages/Pigments/Calcium_Carbonate) which will react with the acid in the same foamy fashion as bicarbonate (baking soda) and vinegar.

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [February 25, 2003, 5:28pm UTC](https://boards.straightdope.com/t/unexpected-chemical-reaction-in-art/157422/4 "2003-02-25T17:28:24Z")

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I believe the name you are looking for is _decoupage_. 🙂

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**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\
**Post date:** [February 25, 2003, 6:45pm UTC](https://boards.straightdope.com/t/unexpected-chemical-reaction-in-art/157422/5 "2003-02-25T18:45:50Z")

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Thanks, QED! That’s the ticket! 😉 - Jinx