RayCrete FAQ Answers to the Most Common Questions

Is RayCrete an Epoxy? No. RayCrete is NOT an Epoxy. RayCrete is a two part polyurethane based adhesive that has more in common (chemically at least) with Gorilla Glue and Elmer's Pro Bond than with epoxy.

Is RayCrete as Strong as Epoxy? Not Generally. Many epoxies are used in making air craft bodies. We wouldn't recommend making planes out of RayCrete. The strength of RayCrete is more in line with concrete rather than epoxy.

Can I Work with RayCrete While It is Curing? Yes. RayCrete changes it's consistency over time. When first mixed together RayCrete is liquid enough to pour into the smallest cracks. After 5 minutes RayCrete becomes like a paste that can be applied to vertical surfaces. Between 10-40 minutes RayCrete is like a clay or putty that can be trimmed or carved to reduce sanding time. At only 2 hours RayCrete is like a piece of wood that can be worked with power tools such as disc sanders, drills and lathes.

Does RayCrete Stick to Itself? Yes. RayCrete forms a seamless bond when applied directly to itself. NO surface preparation is needed and it bonds to itself at any time during its curing cycle.

Does RayCrete have any Flammable Vapors? No RayCrete has NO Volatile Organic Compounds (VOCs) and Negligible Volatile Inorganic Compounds. In other words, there are no fumes, no vapors, no breathing hazards. A pleasant change from other pungent smells in epoxy products.

Is RayCrete Safe? Yes. We are at least as safe as other polyurethane based adhesives. In fact we have much less MDI (the chemical compound in polyurethanes that is generally of concern) than the leading polyurethane glues.

Does RayCrete Work Underwater? Yes. RayCrete can be poured into water to form an underwater bond, or it can be applied underwater while it is in the paste stage.

Can RayCrete be Colored? Yes. RayCrete can be colored with any grout coloring power. You can also use titanium dioxide to color it white. Use colored powders, form your local art supply store, to get a wide variety of colors. Water soluble aniline dye can be used to give RayCrete a rock-like appearance.

Can RayCrete be Painted? Yes. RayCrete can be painted and stained. We have not tried out every possible paint or stain, but we have found that water based paints and stains work much better. If you run into a paint or stain that does not take, apply a layer of wood putty or Bondo to give it a surface to grab onto. You may also need to experiment with different (probably water based) primers.

What Happens to RayCrete at Low Temperatures? It Gets Cold. But, more seriously, unlike just about every other two-part adhesive, when it begins to thaw it will continue to cure. We've done this little interrupted curing experiment using dry ice since RayCrete does not freeze until it is well below zero degrees Fahrenheit.

What Does Extended Curing Time Mean? RayCrete changes it's properties from a liquid (0-5 minutes) that flows into the smallest cracks, to a paste (5-10 minutes) that can be used on vertical surfaces, then to a moldable clay material (10-30 minutes) that can be cut or trimmed without altering its strength. RayCrete then hardens to the consistency of hardwood in about two hours. When cured RayCrete can be cut, sanded, drilled, shaved, painted, stained, turned on a lathe, and even nailed without shattering. RayCrete is fully cured in 24 hours. This extended curing time allows you the flexibility you need to make your project right the first time.