Which type of adhesive is best for mosaics? It depends on your base material, mosaic method, whether you're working horizontally on a table or vertically on a wall, whether your mosaic is exposed to moisture, and personal preference.
Many websites and articles say Weldbond is the best adhesive for indoor mosaics and that it's the preferred glue of professional mosaic artists worldwide. I'm the kind of guy who likes to ask, "Why?" I'm compelled to dig deeper, so my question is: What makes Weldbond so much better than other polyvinyl acetate (PVA) glues (commonly known as white glue), such as Elmer's Glue All? If you're like me, you wonder, "Why do so many mosaic websites say Weldbond is the best mosaic glue, but none of them fully explain what makes it better or why it's better?" I don't know, maybe one mosaic artist heard something about Weldbond and regurgitated it to another artist without knowing the chemical facts. Maybe a mosaic supply salesman makes a bigger profit selling a 4-ounce bottle of Weldbond for $4.50 than a 7.5-ounce bottle of Elmer's for only $1.50.
Let's think about it. White glues are made from PVA emulsions. All basic PVA emulsions have the same properties: water-based, odorless, easy clean-up, colorless, relatively non-toxic, water resistant (not waterproof), and not too heat resistant compared to other adhesives.
Varieties of PVA glues can be developed by adding small amounts of materials to improve specific characteristics. For example, simple clay can improve the glue's high temperature strength. However, the differences in varieties aren't that great because if too much extra material is added, the glue's adhering properties unacceptably weaken.
I tried to determine the chemical properties of Weldbond and Elmer's, but I couldn't find anything that fully defines the ingredients. The Elmer's website says their ingredients are proprietary, so I assume Weldbond's ingredients are also proprietary. I also couldn't find independent laboratory test results that define Weldbond's shear strength, adhesion strength, and cohesion strength. (The key word is "independent.") Same for Elmer's. Therefore, I couldn't compare the two to determine if one truly is stronger than the other in shear, adhesion, and cohesion strength.
For our indoor mosaic applications, do we really care if one brand is stronger than the other by a ga-zillion Pascals? (A Pascal is a unit of pressure equivalent to one Newton per square-meter.) I don't think so. For example, do we care that one brand might support the weight of two elephants while the other brand might support only one? Of course not. All we care about is if the glue can effectively hold a small piece of glass tessera that weighs less than an ounce to our base material without extreme external forces acting on it (e.g., forces such as walking on it or beating it with a hammer). So, in terms of strength, how do we choose whether to use Weldbond or Elmer's for our simple, light-duty, indoor, mosaic art application? The answer is easy--perform our own unscientific experiment.
Read the eBook to see the details and results of my experiment and learn which brand performed better. You'll be surprised at the results. The eBook also explains more about PVA glue, so you'll understand whether it's possible to manufacture one brand significantly better than another brand. So, the question still remains: For our indoor glass mosaic art, is it worth it to spend $4.50 for a 4-ounce bottle of Weldbond instead of $1.50 for a 7.5-ounce bottle of Elmer's? Read the eBook!
Bill Enslen has created lovely mosaic art for 30 years. His new eBook, Mosaic Pieces: Essentials for Beginner and Professional Mosaic Artists, gives you step-by-step details for creating your own mosaic masterpieces. Visit his website and read the free sample chapters at Glass Mosaic Tile Art. Let him show you just how easy it is. With Bill's help, you can do it. Yes, you can!
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