Your Source For Epoxy Resin Throughout CANADA
Picking the right epoxy resin for your project is paramount to a successful pour. A river table will require a thicker pour (slower curing) resin compared to coating applications like bar tops and table top epoxy. One of the major differences between resin choices is the rate at which the hardener and the resin reacts and ultimately cures. Table top epoxy usually cures much quicker than a deep pour casting resin. To better help you decide which kind of resin is best for your project, lets dive in a little more...
How To Pick The Right Resin
Picking the right resin is dependent on the project. Will you be coating tumblers, applying epoxy to a bar top or countertop, or will you be creating resin art or jewelry? Each application may require a different type of resin. Table top epoxy is the most popular epoxy resin and is used for coating applications. As the name implies, table top epoxy resin is often used for thin pours on the tops of tables or bars, but is often used for a variety of other applications as well.
Conversely, casting resins are usually much thinner in viscosity and slower curing. This makes castings resins more appropriate for casting deep pour applications like molds, jewelry, and thick river table pours. Thinner resins often cure significantly slower than coating (table top) epoxies, therefore, allowing you to more up to a few inches at a time. That being said, casting resins can often take twice as long to cure compared to coating applications. Each time of resin comes with its own advantages and disadvantages. Although each brand of epoxy resin needs is different, we can usually make the following generalizations.
Table Top vs Casting Resin
Table Top Epoxy
Understanding Epoxy & How To Use It
Epoxy Vs Resin:
Often confused or misunderstood is the difference between epoxy and resin. Epoxy resin is a two-part component, composed of a base resin and a hardener or curing agent. Although the terminology is frequently used interchangeably, epoxy and resin are usually referring to the two-part mixture of a Base Resin & Curing Agent. When combined, the resin and hardener become an epoxy resin which mixes as a liquid and cures as a hard plastic-like material.
How To Measure & Mix:
Properly measuring and mixing epoxy is critical to a proper cure. Incorrect ratio measurements or incomplete mixing are the two most common causes of problems when using epoxy. Coating epoxies like table top and bar top are often 1:1 by volume mixtures. This is 1 part base resin and 1 part curing agent by volume. These are the easiest mixing ratios to measure out. Although 1:1 by volume is the least complicated ratio, ALL RATIOS should be measured with graduated mixing containers to ensure completely accurate measurements.
Casting resins often come in a variety of ratios including 2:1, 3:1 and can even utilize alternative catalysts, which can be an even more complicated ratio/measurement. Utilizing graduated mixing containers is always a great idea when measuring more complex ratios. Alternatively, many epoxies can also be measured by weight. Whether measuring by volume or weight, following the directions precisely is the key to a properly cured project.
Inadequate mixing will also lead to uncured or tacky epoxy. Many coating epoxies require mixing for 3-5 minutes or even longer. When mixing by hand, mixing for 5 minutes can seem like forever. However, failure to mix completely will often leave tacky or soft areas in a finished product. Many will often mix for 3-5 minutes and then pour into another clean, dry mixing container and mix for another 1-2 minutes. It is also important to remember to scrape the sides and bottom of the mixing container to ensure proper mixing. However, when pouring the mixture, do NOT scrape the sides and bottom as this can increase the likelihood of scraping improperly mixed material onto your project.
Mixing volume should also be considered when mixing. Many epoxies have a maximum recommend mixing quantity. The reason for maximum mixing quantities relates to adequate mixing and consideration for an accelerated reaction. For example, mixing more than 1 gallon (half gallon resin and half gallon catalyst) at a time, reduces the likelihood of a complete mixture. Additionally, if mixed epoxy is left in a mixing container beyond 5 minutes (after mixing) and accelerated reaction could occur. An accelerated reaction may cause the epoxy to heat up, yellow, crack or ultimately not cure. Furthermore, many epoxy brands suggest mixing by hand for smaller amounts, and using a power mixer set to hand speed for larger quantities.
Project Prep Work
Understanding a working surface can be the difference between a project with excess bubbling or a project with a smooth, glossy finish. Some surfaces are more porous than other surfaces. If a surface is not properly sealed, air/moisture can release into the epoxy causing bubbles or a hazy finish. Concrete and wood can be extremely porous, which requires proper preparation. A very thin seal coat of epoxy can often be the best way to seal a surface. By pouring a thin coat, the epoxy can soak into the porous areas and air can easily rise to the surface and ultimately pop. When in doubt, its best to always pour a seal coat before your flood coat.
There are many variables to consider when working with epoxy. Its always best to test a small sample area or test piece before applying mixed epoxy to your final project to ensure you achieve your desired result.
WARNING: Oil-Based Stain & Paint
Most epoxies cannot be poured over top of oil-based stains and paints. Oil based products can take very long (often a year or more) to fully cure. Therefore, oil-based stains and paints should be sealed prior to applying epoxy. A water-based (must be water-based) clear coat can be applied over top of the oil based products. Once the water based clear coat has cured, properly mixed epoxy can be applied. If the water based clear coat leaves a shine or gloss, a light sanding is recommended to ensure that the epoxy properly adheres.
If planning a project which will be poured over a shiny/glossy surface (i.e. formica, glossy paint, etc), prepping the surface by sanding may be necessary. If pouring more than one coat of epoxy and waiting extended periods of time (12+ hours), sanding between coats is recommended as well. If in doubt, sanding is likely a good idea. 320 grit is a great go-to starting grit which will adequately scuff the surface to allow the epoxy to properly bond. If sanding, be sure to thoroughly clean the surface before pouring the epoxy. Isopropyl Alcohol 99% (must be 99%) or denatured alcohol are great to clean with so long as they contain no water. Water and epoxy do not mix. Cleaning the surface properly is extremely important to remove all dust particles and other debris that could mix into your flood coat, leading to poor results.
Avoid Water & Moisture
Water/Moisture and epoxy do not mix. This goes for water-based paints as well. If the slightest bit of moisture/water is mixed in with the epoxy, or if the epoxy is poured over an area holding moisture, this can cause the epoxy to become contaminated. This can often result in the epoxy having a hazy finish. Another consideration is pouring in the evening hours, which could result in moisture/condensation to collect on the surface which will also cause a hazy/improperly cured finish.
UV Resistant Epoxy
Almost all epoxy resin is susceptible to yellowing when exposed to UV. However, some epoxy resins have better resistance to yellowing than others. Factors determining the ability to resist yellowing include raw materials used, as well as the level of UV inhibitors. Although many epoxies are advertised as UV Resistant, most are not meant for permanent outdoor use or exposure to direct sunlight or ultraviolet rays.
The Accelerated UV Exposure image shows how the epoxy can yellow over time. Over time, some epoxy becomes a darker amber color and loses its' clarity. Additionally, the hardener/curing agent can yellow in an unmixed container over time, especially past a year.
Bar Top & Countertop Projects
When picking an epoxy resin for a bar top or countertop project, a few more features must be considered. A bar and table are areas of high use/traffic. Therefore, the cured epoxy should be durable, scratch resistant, yet maintain its' ultra clear appearance. Many coating epoxies offer an impact and blemish resistant finish. However, if the top coat becomes scratched over time, the epoxy can be sanded and poured again. This is the beauty of using epoxy. If sanding and pouring a new coat is not an option, buffing may be a possibility. 3M Finess It II works well for buffing cured epoxy. Be very cautious when considering compounds as some may not be conducive to cured epoxy.
Resin Art & Tumbler Projects
Resin art is becoming more and more popular and applied to a variety of substrates. Art resin projects typically utilize colored epoxy and pigment powders to color the epoxy. Because the epoxy flows and self levels, colors often swirl and mix creating a beautiful piece. Certain colors and patterns can also be combined to create faux marble or granite finishes for countertops, which is becoming a increasingly popular alternative to actual granite or marble.
An even more recent trend in epoxy usage is for tumblers. Again, because the epoxy can be colored, glittered or even metallic pigments added, a variety of customization options exist for tumblers. However, because many coating epoxies are self leveling and take up to 20-30 minutes to gel, many tumbler resin artists utilize a cup turner or a "cuptisserie." A cuptisserie continually rotates a tumbler at a consistent speed so that the epoxy levels evenly across the surface while gelling and curing. After the epoxy has cured, it leaves a smooth, high gloss finish.