Sikasil GP-101 High-Performance Silicone Sealant

Sikasil GP-101 is a general purpose, one-component, non-sag RTV acetoxy silicone sealant for general sealing and bonding. It cures from moisture in the air to a soft elastomer (Shore A 20, 400% elongation), accommodates ±25% joint movement per ISO 11600, and comes in a 295 ml cartridge in seven colors. Stone fabricators commonly use it on natural stone, with one exception: quartzite and certain white marbles can stain, so we steer those jobs to a neutral cure silicone (see Natural Stone and Countertop Fabrication below). Chemical Concepts sold it before as Bondaflex #100, and it is the same general purpose acetoxy silicone now supplied under the Sika name. Made in the USA.

Key Product Details

Natural Stone and Countertop Fabrication

In our experience, Sikasil GP-101 is commonly used on natural stone, and stone fabricators buy it for countertop work. The exception is stain. Acetoxy cure silicones like GP-101 can stain quartzite and certain white marbles. On those stones we recommend a neutral cure silicone: Silco RTV-7500 or Sikasil N Plus.

• Test a scrap of the actual stone before you run a joint, and again whenever you change stones.
• Use a neutral cure silicone on quartzite and on white marble.
• Sika’s data sheet lists natural stone such as marble, granite and quartzite as not recommended for GP-101 because of staining, so the scrap test is your protection.
• Call us with the stone and the joint, and we’ll tell you which silicone fits.

How RTV Acetoxy Silicone Sealing Works

Sikasil GP-101 cures from moisture in the air, so there is nothing to mix. The steps below follow Sika’s directions.

• Prep the surface. It has to be clean, dry and free of grease, oil and dust. How you treat the substrate decides how long the bond lasts.
• Check temperature. Sikasil GP-101 applies between 5 and 40 °C (41 and 104 °F). Substrate and sealant work best between 15 and 25 °C (59 and 77 °F).
• Size the joint. Joints must be properly dimensioned, and joints deeper than 15 mm must be avoided.
• Dispense it with a hand, pneumatic or electric piston gun.
• Tool inside the 15 minute skin time. Press the sealant against the joint flanks to wet the bonding surface. Sika says no tooling agents are to be used.
• Let it cure. Cure slows at low temperature because the air holds less moisture. Sika’s curing speed diagram in the TDS shows cure depth at 10 °C and 23 °C.
• Leave it unpainted. Sika says Sikasil GP-101 cannot be overpainted.
• Clean up. Remove uncured sealant from tools with Sika Remover-208 or another suitable solvent. Cured sealant comes off mechanically only. Wash skin right away with industrial hand cleaner and water, and keep solvents off skin.

Where Not to Use Sikasil GP-101

• Painted joints. Sika says it cannot be overpainted.
• Submersible applications.
• Concrete, fibrous cement and mortars. Sika says not to use it on these because of acetic acid.
• Contact with lead, copper, brass or zinc, because of corrosion.
• Contact with some organic elastomers such as EPDM, APTK and neoprene, where it may discolor.
• Structural glazing and aquariums.

Sika lists Sikasil GP-101 for experienced professional users only, and says tests on your actual substrates and conditions have to confirm adhesion and material compatibility. The full data is on the Sika Sikasil GP-101 product page.

Performance in Production

• ±25% joint movement per ISO 11600, Shore A 20 hardness and 400% elongation give a soft seal for joints that move.
• Sika lists superior UV and heat resistance, and service temperature runs from -40 to 180 °C (-40 to 356 °F).
• A 15 minute skin time at 23 °C (73 °F) and 50% r.h. means you tool right after you gun the bead. Plan your run around it.
• Sika rates it very good for gunning and tooling.
• It is solvent free.
• A 1.1 MPa (160 psi) tensile strength suits sealing and general bonding. If a joint carries structural load, test the bond first or call us about a structural adhesive.
• A 24 month shelf life, stored below 25 °C (77 °F), makes it easy to keep on the shelf.
• Some colors are listed under NSF/ANSI 51 for food equipment materials. Sika’s TDS says the listing depends on color, so confirm the color you need.

Common Applications

• Natural stone and countertop fabrication, with a scrap test first and a neutral cure silicone on quartzite and certain white marbles.
• Food equipment assembly, using a color Sika lists under NSF/ANSI 51.
• Appliance assembly.
• General sealing of windows.
• HVAC sealing.
• Truck and trailer sealing.
• RV sealing, including awning components.

Available Sizes

Translucent is also available in a 5 gal pail made to order. Call us for current availability.

Frequently Asked Questions

What is Sikasil GP-101 used for?

Sikasil GP-101 is used for general sealing and bonding. Sika lists food equipment and appliance assembly, plus general sealing of windows, HVAC, trucks, trailers and RVs, and stone fabricators commonly use it on natural stone. It is an RTV acetoxy silicone, so it cures from moisture in the air with no mixing.

Is Sikasil GP-101 the same as Bondaflex #100?

Yes. Sikasil GP-101 is the general purpose acetoxy silicone Chemical Concepts used to sell as Bondaflex #100. Bondaflex Sil 100 GP and Bondaflex #100 are the old names, and the product now ships under the Sika name.

Can you paint over Sikasil GP-101?

No. Sika says Sikasil GP-101 cannot be overpainted. If the joint has to be painted, call us about a paintable sealant.

Can you use Sikasil GP-101 on natural stone?

Yes, it is commonly used on natural stone, with exceptions. Acetoxy cure silicones can stain quartzite and certain white marbles, so test a scrap of your stone first and use a neutral cure silicone on those. Sika’s data sheet lists natural stone as not recommended because of staining, which is why the scrap test matters.

What silicone should I use on quartzite or white marble?

Use a neutral cure silicone. We recommend Silco RTV-7500 or Sikasil N Plus for quartzite and certain white marbles, where an acetoxy cure silicone like GP-101 can stain. Test a scrap first, and call us if you want help picking between them.

Is Sikasil GP-101 NSF listed for food equipment?

Yes, for some colors. Sika lists it under NSF/ANSI 51 for food equipment materials and says the listing depends on color. Sika’s data sheet does not say which colors are listed, so confirm the color you need before you specify it.

How fast does Sikasil GP-101 skin over?

Skin time is about 15 minutes at 23 °C (73 °F) and 50% relative humidity. Tool the bead inside that window. Cure runs slower in cold or dry conditions, and Sika’s TDS includes a curing speed diagram at 10 °C and 23 °C.

What colors and sizes does Sikasil GP-101 come in?

Seven colors: clear (translucent), white, transwhite, bone, black, aluminum and almond. Each comes in a 295 ml cartridge, 24 per case, with a 24 month shelf life stored below 25 °C (77 °F).

Questions on fit for your sealing application, or on which silicone suits your stone? Call (800) 220-1966 or email [email protected].