If there’s one product that should be part of any construction toolbox, it’s silicone sealant. This material is highly durable and flexible and offers a convenient way to seal gaps.

But can you melt silicone? Read on to learn more about silicone sealant’s thermal properties and how it stands up to temperature extremes.

A Great Option For Harsh Weather Conditions

Silicone sealant is an adhesive commonly used in construction and DIY projects today. Its primary ingredient, silicone, is composed of multiple elements capable of resisting weathering, UV light, and, notably, heat.

Unlike many other organic materials,silicone can maintain its structural integrity under a wide range of temperatures. Most silicone sealants can withstand temperatures as high as 260 degrees Celsius (500 degrees Fahrenheit) and as low as -60 degrees Celsius (-76 degrees Fahrenheit). As such, it’s ideal for surfaces that are exposed to extreme heat or cold.

Does it Melt?

Melting refers to the process by which a solid substance transitions to a liquid state. This transition does not occur in silicone sealants the same way it does in substances like ice or wax — it lacks a defined melting point.

So, while silicone doesn’t technically melt, it does undergo a process called degradation. When exposed to temperatures beyond their threshold, silicone sealants experience thermal degradation, a chemical process in which the bonds within the silicone polymer begin to break down.

This doesn’t result in silicone becoming liquid, as would be the case in traditional melting, but leads to a loss of the sealant’s properties, such as elasticity and adhesion.

Can You Melt Silicone Back Together?

No, not really. While thermoplastics can be melted and reshaped multiple times, thermoset materials like silicone are specifically designed to retain their shape and strengtheven under high heat conditions.

Once cured or set, this material becomes chemically cross-linked. In other words, it’s impossible to re-melt or fuse back together in the way that materials like plastic and wax are. If you want to repair or join silicone objects, you’ll have to purchase a special adhesive capable of bonding to the surface and creating an adequate seal.

Factors Influencing Heat Resistance

Silicone’s heat resistance depends very much on the type in question. Some formulations stand up to temperature extremes much better than others. For example, some high-performing sealants are capable of withstanding higher temperatures thanks to fillers that boost their thermal stability.

Finding a Sealant That Can Withstand the Heat

Because they don’t melt, silicone sealants are often the preferred choice of those looking to seal gaps or create bonds on various surfaces. But how can you be sure a sealant really does what it claims to? What factors should you consider before buying?

Here’s how to ensure you find a melt-free, high-quality product.

Evaluate the Temperature Range

While all silicone sealants offer a high degree of heat resistance, some are particularly suited to withstand hot conditions. Sealants are generally rated by the maximum and minimum temperatures they can endure without degrading.

Be sure to choose a sealant that lists this information on the packaging. Pay close attention to the specific temperature range advertised. For instance, if you plan on using the sealant in an environment where temperatures frequently reach 300 degrees Celsius, you’ll want to look for a sealant that can withstand temperatures of at least 300 degrees.

Research Chemical Composition and Performance

Every sealant is a little bit different. Different applications require different chemical compositions, so be sure to look for sealants that are specifically formulated for heat resistance. These sealants typically contain additives that enhance theirability to withstand high temperatures without losing their adhesive properties or becoming brittle.

Look for Adhesion and Flexibility

Heat resistance may be your top concern, but don’t sleep on adhesion and flexibility. The best sealants have no problem adhering to a variety of surfaces, forming strong, durable bonds. Make sure the sealant remains flexible after curing — this helps accommodate any thermal expansion or contraction of the bonded materials.

Consider Curing Time and Ease of Application

Some products are notorious for having long curing times. Thankfully, silicone isn’t among them, but certain types can still take several days to fully set. Choose a sealant that aligns with the timeframe of your project and will allow you to complete it on schedule and without hassle.

Pay Attention to Certifications and Industry Standards

Quality silicones adhere to the highest industry standards. Avoid overlooking the product’s certifications, as these can be a strong indicator of quality and reliability. Remember, too, that the cheapest product isn’t always the best product. Poor quality leads to poor workmanship, which can end up costing you more in the long run, so don’t be afraid to shell out a little more for a decent sealant.

Read Brand Reviews

In addition to researching the product’s certifications, consider browsing manufacturer reviews to ensure you’re buying from a reputable seller. Most websites feature dedicated review pages, but if you can’t find one for the manufacturer in question, try looking on Google.

Other Considerations For Using a Heat-Resistant Sealant

Handy though they are, silicone sealants are not without their downsides. Before committing to a product, make sure you know what you’re getting and what, if anything, you’ll be sacrificing for a strong seal.

One of the main things to think about is environmental impact. Some silicone-based products contain chemicals that are harmful to the environment. When these sealants degrade or are improperly disposed of, they can release toxic substances.

To limit your carbon footprint, be sure to look for eco-friendly sealants. An increasing number of manufacturers are developing environmentally-friendly products, leaving buyers with more options than ever before.

Another less-than-ideal characteristic of silicone sealants is their impact on human health. They often emit volatile organic compounds (VOCs) during curing, which can be harmful if inhaled in enclosed spaces. The good news is this is fairly easy to get around by ensuring adequate ventilation during application. You might also try looking for a low-VOC or VOC-free sealant.

Will your sealant adhere to the material in question? Make sure to choose a product that can bond well to the surface you’re working with. This material is highly flexible and compatible with multiple types of surfaces, but it’s still a good idea to check the details.

Take acetoxy sealants. They cure with the release of acetic acid and can corrode certain metals. For this reason, they may not be suitable for use on sensitive surfaces.

Finally, consider the shelf life and storage condition of the sealant. Be aware that some products have a limited shelf life and can degrade if stored improperly. Check the expiration date and make sure you’ll be using it before it expires.

Silicone Depot Has the Heat-Resistant Sealant You Need

New and improved silicone sealants are entering the marketing all the time, leaving consumers spoiled with choice. The only downside to that is it becomes harder to make an informed decision — after all, you don’t want to waste your money on an inferior product that’s going to damage your project.

Silicone Depot offers quality sealants capable of withstanding extreme temperatures, including thisHi-Temp Red & Blue 100% RTV Silicone Sealant & Gasket-Maker capable of withstanding temps of up to 650 degrees Fahrenheit.

Give us a call today at 812-824-8000 for help finding the perfect sealant for your project.