In the know: High-Temperature Epoxy
There are countless types of epoxies, so knowing whether heat resistant epoxy is what you really need, can prove to be challenging. Often pipe repairs, vehicle repairs, concrete bondings, and crack castings can present temperature challenges. The last thing you need is an epoxy that will soften when heat is applied.
What Is the Max Temperature of Epoxy?
Heat resistant epoxy can come in several variations. While a DIY epoxy kit will commonly only withstand temperatures up to 150 degrees, there are other epoxies out there that can withstand extreme heat up to 600 degrees. These are specially formulated with fillers like quartz, and offer abrasion resistance and high-heat curing.
With these epoxies being thermally conductive, they are fantastic for encapsulation and potting, as well as for providing exceptional chemical resistance and withstanding steam exposure. These are active and aggressive epoxies that can stand up to shock, prolonged vibration, and extreme heat. The right industrial high-heat epoxy can withstand heat of more than 1500 degrees due to its unique curing agents, carbon fibers, and flexible rod structures. These are commonly found in the components of an aircraft.
What You Need to Know About Epoxy
Epoxy offers unmatched durability, chemical resistance, and strength for bonding. It has a low porosity and is great for using as an overlay. Most are mixed in a two-compound method that must be explicitly followed per kit instruction since each package may vary in approach. Therefore, reading the packaging is essential anytime you are working with a new brand.
It is vital to remember that once the compounds are blended, you are only getting about an hour of pot life, so be ready to use it. Once the pot life has expired, the mixture can become extremely hot and harden relatively quickly. While the epoxy may harden in just a couple hours, actual curing can take a couple of days. Using epoxy in temperatures ranging from 64-85°F is best, with the optimal around 72°F.
Once the epoxy is cured, it can withstand temperatures well below 0°F, however, around 140°F the epoxy will start to soften--it will harden again once temperatures recede. If you plan on using a surface that will come in contact with hot items, using high-temperature epoxies will ensure you don’t have to worry once it is cured.
High Heat Epoxy 101
When epoxy is exposed to higher temperatures, its thermal, mechanical, and electrical properties will change. The glass transition temperature (Tg) of the epoxy can sometimes be affected. This is when your epoxy will turn from a state of glass to rubber.
Sometimes the epoxy properties will not convert back to their hardened state, meaning the epoxy will stay soft. Using the right epoxy is critical for your unique project's needs. You will want to use the heat deflection temperature (HDT) rather than the Tg method when choosing and using a commercial high heat epoxy.
Be mindful that curing these epoxies may require additional heating methods exceeding the Tg. Silicate-based coatings are exceptional to use in high-temperature environments. When using a heat-resistant epoxy, you will get several benefits including: durability, strength, thermal conductivity, stability, flame retardancy, transparency, machinability, UV curability, and even superb flexibility.
Are High Heat Epoxies Clear When Cured?
Heat resistant epoxy is fantastic to use if you want a shiny finish, but not all of them will cure crystal clear, especially the paste type. Some heat resistant epoxies will cure with a yellow tint. You will need to read the packaging and check with the retailer or manufacturer before deciding on a brand, to be sure you get the right one for your needs.
In Conclusion, you can use epoxy for several projects from bonding and sealing to coating. This is a noncorrosive and lightweight method, offering mechanical and conductive qualities. High heat epoxy can be used for mechanical repairs, bonding for vehicles, aircraft devices, and electronic devices. It can withstand steam, shock, and vibration, making it suitable for industrial use. So, if you are looking for an extremely strong, resilient, and dependable bond, sealer or coating agent that can take the heat, high-temperature epoxy may be exactly what you need.