Make non-toxic fake window frost for winter decorations and crafts using a simple mixture of urea and water. Decorate windows, mirrors, ornaments, or other surfaces. Unlike real frost, the fake frost does not melt. It washes away easily with water without harming the glass. Here’s what you do.
Fake Window Frost Materials
The key ingredient is urea or carbamide. This chemical is available at garden supply stores and online.
- 300 grams urea (carbamide)
- 50 milliliters hot water
Make Fake Window Frost Crystals
- Pour 300 grams of urea into a cup or glass.
- Stir in 50 milliliters of hot water. Not all of the urea dissolves and that’s fine.
- Dip a paintbrush, paper towel, or kitchen towel into the liquid and paint it onto a window, mirror, or other glass or plastic surface. For full coverage, coat the surface twice.
- After a few minutes (as the surface dries), watch crystal frost patterns appear.
- Start with very hot tap water. The amount of urea that dissolves depends heavily on temperature. So, if you use lukewarm or cold water you might not get enough chemical dissolved to form pretty crystals.
- Consider wearing disposable gloves. Urea is not harmful, but it can irritate skin and feel itchy.
- Warm water rinses the solution off your skin and dissolves the crystals off of surfaces.
- If you like, make the crystals permanent. After they dry completely, spray the surface with a sealant or top coat.
Grow Urea Crystals
Since you have urea, another easy project is growing urea crystals. In fact, if you don’t use all of the fake frost solution, you’ll grow crystals in your container. But, if you want a nice mass of crystals, follow these steps:
- Pour hot water into a small container.
- Add urea until no more dissolves. You have a saturated solution when you have undissolved solid in the bottom of the container. The solubility of urea in water is 545 g/L at 25 °C. It is much more soluble at higher temperatures.
- Filter the liquid through a coffee filter into a clear container so you can watch the crystals grow.
Slow cooling produces the largest crystals. Fast cooling produces smaller crystals very quickly.
About Urea or Carbamide
Urea or carbamide is an organic compound with the chemical formula CO(NH2)2 or CH4N2O. Its systematic name is carbonyl diamine. Urea is crystalline, colorless, odorless, and non-toxic. Usually, you find it as clear to white crystals or powder. Humans and other mammals excrete it in urine, but it is most often encountered as plant fertilizer. Other uses of urea include resins, catalytic converters, road de-icers, hair removal, skin lotion, and food additives. Although it is not toxic, urea can cause skin irritation. If you get it on your skin, rinse it off with water.
- IUPAC (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. doi:10.1039/9781849733069-FP001 ISBN 978-0-85404-182-4.
- Meessen, J.H.; Petersen, H. (2010). “Urea”. Ullmann’s Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a27_333
- Yalkowsky, Samuel H.; He, Yan; Jain, Parijat (19 April 2016). Handbook of Aqueous Solubility Data. ISBN 9781439802465.