Custom Sizes, Any Quantity… From Single Prototype to Full-Scale Production..
Custom Sizes, Any Quantity… From Single Prototype to Full-Scale Production..
Most common elastomers break down rapidly above 120 degrees Celsius. Standard rubber seals harden and crack after very short heat exposure. For these applications, silicone rubber bellows have no real equivalent. They retain all core properties across an extremely wide temperature range. No other flexible sealing material comes close to this level of performance.
Most design engineers now specify silicone rubber bellows for any high heat role. They remove all risk of unexpected and costly seal failure. This makes them the default choice for most demanding industrial applications.
Most standard industrial silicone bellows operate continuously between 200°C and 250°C. This range holds for thousands of hours of uninterrupted running time. For short peak exposure they will reliably withstand up to 300°C. The pharmaceutical grade bellows are tested to ensure zero extractables at operating temperature.
The specialised high temperature grades handle brief peaks up to 350°C. The same material also remains fully flexible down to -65°C. No other common elastomer comes close to this operating window. It will not crack, harden or permanently deform across this range. The medical silicone bellows can be supplied with full traceability for every production batch.
Most other elastomers break their molecular bonds above 120°C. Silicone has a silicon-oxygen backbone instead of carbon. This bond is around 50% stronger than the equivalent carbon bond. It does not suffer thermal degradation at normal operating temperatures.
Oxidation proceeds at a negligible rate even at 250°C. The material retains all of its original elasticity at peak temperature. It also has very low thermal conductivity compared to most materials. Viscosity changes remain stable and predictable across the full range. This consistent performance makes it an ideal base material for medical silicone bellows.
Metal bellows were the standard for high temperature use for many decades. Silicone bellows offer significantly better flexibility across all temperatures. They do not suffer from fatigue cracking after millions of cycles. The FDA bellows are available in all standard and custom sizes.
The material is around one seventh the weight of equivalent stainless steel. Installation takes a fraction of the time required for metal assemblies. They provide far superior vibration dampening for moving machinery. The long term maintenance requirements are non-existent. This lack of particulates makes them the first choice for pharmaceutical grade bellows.
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Silicone Grade Specifications |
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Grade Type |
Max Temp (°C) |
Shore A Hardness |
|
Standard VMQ |
200 |
40-80 |
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High Temp PVMQ |
250 |
50-70 |
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Ultra High Temp |
300 |
60-80 |
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Low Temp Grade |
200 |
30-60 |
|
FDA Compliant |
180 |
40-70 |
The actual maximum temperature of a finished bellow depends on far more than base material. Six separate factors combine to determine the performance of any unit. The food safe rubber bellows are suitable for continuous contact with all food types.
1. Durometer Rating
Softer lower durometer materials generally have lower heat resistance. Harder 70 and 80 durometer silicones offer the highest continuous temperature rating. Selection of a durometer is always a balance between flexibility and heat performance. This balance is important for FDA bellows used in process equipment.
2. Additive Compounds
Specially formulated additive packages can boost continuous temperature by 30°C. These additives do not alter the elasticity or other physical properties of the material. They work by slowing the oxidation process at very high temperatures. Units manufactured for high temperature process use are autoclavable silicone bellows.
3. Wall Thickness
Thicker wall sections transfer heat more slowly through the material. This can create internal hot spots that reduce the effective maximum temperature. Thinner walls provide better heat dissipation and higher performance. The USP Class VI bellows are the standard for all clean room applications.
4. Design Geometry
The sharp internal corners and tight folds create localised stress hot spots. These points will degrade far faster than the rest of the bellow structure. The good design eliminates these features to maximise operating life.
5. Curing Process
The exact curing method used determines the final bond structure. The properly post cured material will operate 20°C hotter than equivalent uncured material.
6. Quality Control
Consistent production and testing ensure every unit meets the stated rating. Small variations in processing can result in large variations in final performance. Their consistent production is a critical requirement for USP Class VI bellows.
We manufacture high performance silicone rubber bellows for extreme temperature applications. All of our medical and process products are FDA 21 CFR compliant bellows. We engineer custom solutions that meet exact specific heat resistance requirements. Our expertise covers aerospace, automotive and industrial sectors. Thermal performance is the primary design driver for all of our products.
We hold full material approvals for food safe rubber bellows for all food processing applications. We test every design to confirm performance at maximum stated temperature. No unit leaves our facility without full validation of all thermal properties.
We can adjust any design to meet specific temperature requirements for any application. We also supply a full range of pharmaceutical machinery bellows for all common equipment lines.
1. How hot can silicone rubber bellows get before they fail?
Standard grades run continuously between 200–250°C for thousands of hours, with short peaks up to 300°C. Specialised high-temp grades can briefly handle up to 350°C — and stay flexible down to -65°C.
2. Why doesn't silicone break down like regular rubber at high heat?
Silicone has a silicon-oxygen backbone instead of carbon, and that bond is roughly 50% stronger. So oxidation and bond breakdown happen far more slowly, even at 250°C.
3. Are silicone bellows better than metal bellows for hot environments?
Yes — they're about a seventh the weight of steel, resist fatigue cracking, dampen vibration better, and don't shed metal particulates over time.
4. What actually determines the heat rating of a finished bellow?
Six things matter beyond the raw material: durometer (hardness), additives, wall thickness, fold geometry, curing process, and quality control. Each can shift the real-world max temperature.
5. Can silicone bellows be used in food or pharma applications at high heat?
Yes — FDA-compliant and pharmaceutical-grade options are tested for zero extractables, are autoclavable, and meet USP Class VI standards for clean-room use.
Conclusion
The silicone rubber bellows do not break down at high temperatures. It will retain flexibility and sealing force for many thousands of hours. It does not suffer permanent deformation even after repeated thermal cycles.
The engineers no longer need to compromise between flexibility and heat resistance. They provide consistent and predictable performance over very long service lives. They reduce unplanned downtime and cut long term maintenance costs. They work equally well at extreme high and extreme low temperatures.
Silicone rubber bellows stay flexible and strong across a much wider range of temperatures than any other common rubber. If you need bellows for high heat, cold or food grade applications, we can help you specify the correct silicone grade for your exact requirements. All quotes are completely free and with no obligation. Reach us any time at +1 917-730-4350 or email info@customrubber-bellows.com.
