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FD18 Putty Liquid Gap filler Material for thermal interface
A blue circle is filled with evenly spaced horizontal black lines, creating a striped pattern reminiscent of LED modules. The lines make the blue color appear as alternating light and dark blue horizontal stripes within the circle against a white background.

FD18 – Gap Filler Putty

Liquid non-hardening silicone gel with heat conduction

FD18 is a soft and compliant, ceramic-filled, silicone based thermal gel like putty that is ideal for applications where large gap tolerances are present.

Thal Article Number: FD18

Performance Materials: Gap Filler Putty

FD18 – Gap Filler Putty

FD18 delivers superb thermal performance and electrical isolation properties.

The unique viscous formulation of FD18 eliminates bleed and pump-out during operation.

The compounds compliant nature result in little or no pressure exertions between   mating surfaces and differences in the bond line at the interface are also controlled more easily.

FD18 is applied like grease and easily via manual, semi-automatic and automatic dispensing.

Ordering Example

Very nice to work with. This is exactly what we were looking for for our project!


FD18 – Gap Filler Putty specifications

Properties Unit FD18 Test Method
Base material
Ceramic filled silicone gel
Light grey
Thermal resistance @ 0.25mm layer
ASTM D5470
Thermal resistance @ 0.5mm layer
ASTM D5470
Thermal conductivity
ASTM D5470
Operating temperature
-40 up to 200
Dielectric strength
Volume resistivity
> 1014
ASTM D2240
mPa.s (cP)
4,000,000 to 8,000,000
Viscocity @ 23ºC, Brookfield RV, TC spindle Helipath @ 0.5 rpm
Outgassing TML
wt % / vol%
0.34 / 0.92
Outgassing CVCM
wt % / vol%
0.09 / 0.24
Flame rating
Standard packaging
10, 30 and 55 syringes 100, 170 and 305 cartridge
Performance Materials: Gap Filler Putty

Interested in FD18 – Gap Filler Putty?

Thal Technologies, located in Almere, has been a pioneer in thermal management and LED lighting solutions for over two decades. Our commitment to innovation and excellence drives us to deliver top-tier thermally conductive and electrically insulating materials across a spectrum of electronics applications.

As industry leaders, we excel at tackling complex challenges in thermal management. Our comprehensive approach encompasses consultation, design, assembly, and manufacturing, ensuring that every solution is not only effective but also seamlessly integrated.

At Thal Technologies, we understand the critical importance of precision and reliability. Our tailored solutions are designed to enhance performance and efficiency, making us the partner of choice for businesses seeking cutting-edge thermal management and lighting solutions.

Request a quote or come visit us in Almere, the Netherlands. The coffee is already brewing! We look forward to discussing how we can assist with your needs.
Marko Widman Thal Technologies
Marko Widman
Office Sales T.I.M.
Frequently Asked Questions

FD18 – Gap Filler Putty frequently asked questions

Welcome to the FAQ section for Thal Technologies’ Thermal Interface Materials. Here, you’ll find answers to the most commonly asked questions about our high-performance thermal solutions. Whether you’re seeking detailed information about our product offerings, customization capabilities, or technical support, this section is designed to provide you with the information you need. If your question isn’t addressed here, please feel free to contact us directly. Our team of experts is always ready to assist you in finding the best thermal management solutions for your specific applications.

We offer a wide range of thermal interface materials, including thermal tapes, gels, gap fillers, liquid gap fillers, adhesives, pastes, phase change materials, and graphite films. Each type is designed to enhance thermal conductivity and electrical insulation. Please refer to our specific product pages for more information or talk to one of our experts. Also, feel free to request a free sample or sample box. 

Yes, we specialize in customizing thermal interface materials to meet your unique specifications. Our team can tailor materials to any shape or form required and adjust formulations based on your specific needs.

Our thermal interface materials are used in various industries, including power electronics, IoT & sensing, aviation, automotive, energy, and LED lighting.

We adhere to strict quality control processes and comply with international standards such as ISO 9001. Our materials undergo rigorous testing to ensure they meet the highest performance and reliability standards.

Yes, we provide rapid prototyping services to quickly develop and test custom thermal interface materials, allowing for efficient iterations and adjustments based on your feedback.

Absolutely. We can combine, tweak, and customize materials to meet specific client requirements, ensuring the final product perfectly aligns with your application needs.

You can request a custom solution by contacting us via email at or by phone at +31 (0)36 202 60 60. Our team will work closely with you to understand your needs and develop a tailored solution.

Our thermal interface materials provide enhanced thermal conductivity, electrical insulation, and reliability. They are designed to improve the performance and efficiency of your electronic systems.

Yes, we offer ongoing support to ensure your thermal interface materials continue to perform optimally. Our team is always available to provide technical assistance and address any issues that may arise. 


For further inquiries or to discuss your specific thermal interface material needs, please contact us at or +31 (0)36 202 60 60.