509 ASI Aquarium Silicone Sealant is a one-part, RTV Silicone. It cures into a durable, long-term rubber that is aquatic life safe.

Due to it’s exceptional tensile, elongation and tear strength it has been used for decades by leading aquarium manufacturers in production use as well as repair. ASI 509 Aquarium Sealant has excellent clarity and offers excellent primerless adhesion to glass. ASI 509 Aquarium Sealant can be used in both saltwater and freshwater tanks to create a waterproof seal. Because it is a thick sealant, it can be applied to Vertical and overhead applications without sagging or slumping.


  • Aquatic Life Safe
  • Made For Aquarium Manufacturing & Repair
  • Excellent Adhesion & Clarity
  • Creates A Durable, Waterproof Seal
  • Excellent Tensile Strength & Versatility
  • One-Part, Easy To Use & Tool
  • Extremely Resistant To Degrading, Non-Yellowing
  • Use In Salt Or Fresh Water Aquarium

Water Immersion Study

Days Immersed In WaterForce Required To SeparateFallure Mode (Cohesive Optimal)
1212 (psi)Cohesive Failure (Excellent)
7209 (psi)Cohesive Failure (Excellent)
90206 (psi)Cohesive Failure (Excellent)
180208 (psi)Cohesive Failure (Excellent)
300203 (psi)Cohesive Failure (Excellent)

Physical Properties

Physical PropertiesTest MethodResult
ViscosityASI Test Method700,000 cps (Spindle 7, 4 rpm)
Skin Formation TimeASI Test Method10 minutes (70°F, 50% RH)
DensityASTM D14758.5 lbs./gal
HardnessASTM C66127 (Shore A)
Tear StrengthASI Test Method45 (Die B, Ibs./in)
Tensile StrengthASTM D412520 psi
Elongation at BreakASTM D412500%
Application TemperatureASI Test Method-35°F to 150°F
Gun GradeASI Test MethodPass (Non-Slump)
QUV TestingASTM G154Pass (10,000 hrs.)
Service TemperatureASI Test Method-50°F to 400°F
Typical Cure RateASI Test Method24 hrs. (1/8" bead)

Strength will start to develop immediately and continue increasing for 7 days after application. ASI recommends testing strength and adhesion on the 7th day. ASI 509 Aquarium Sealant suggested application temperature range: -35°F to 150°F. ASI recommends waiting for full cure (7 days) prior to using the aquarium.

Information on this data sheet can change without notice and it is therefore not recommended that these figures be used in spec writing. If you have any questions contact manufacturer‘s sales and technical service department.

Conforms / Meets / Exceeds

  • FDA Regulation No. 21 CFR 177.2600 VOC Compliant (23 grams/liter AST D2369)

Common Substrates

  • Glass
  • Most Acrylics
  • Aluminum
  • Metals
  • Most Woods
  • Some Plastics
  • Porcelain
  • PVC
  • Steel

Common Applications

  • Aquarium Manufacturing
  • Terrarium Manufacturing
  • Glass Viewing Panels
  • Sealing/Bonding Aquarium Filters
  • Aquarium Repair
  • Terrarium Repair

For a complete list of applications & substrates or more product information, please contact us.

Speak with a sales engineer to discuss 509 ASI Aquarium Silicone or any of our other products or manufacturing services! Use our contact form or call 800-325-7040 now.