WACKER Primer G 791 A/B – Addition-curing primer for silicone rubber & substrate adhesion
WACKER Primer G 791 A/B – Addition-curing primer for silicone rubber & substrate adhesion
Temporarily sold out
Leave your email address and we will let you know as soon as this variant is back in stock.
Variant: 100 gram Set [50 gram A + 50 gram B]
You will only receive a message about this product, no newsletter.
In stock
Ordered and paid on a working day: usually ships the same day
Delivery to Netherlands: usually within 1 working day
In stock
Ordered and paid on a working day: usually ships the same day
Delivery to Netherlands: usually within 1 working day
- 30-day returns
- Over 100,000 happy customers
- Pay later with Klarna
- Personal advice from material experts
Question about this product? Our material experts are happy to help you choose the right product. Contact us
Premium addition-curing primer for professional silicone-to-silicone and substrate adhesion
WACKER® PRIMER G 791 A/B is a two-component, addition-curing priming system diluted in an organic solvent. The primer is applied to the substrate and, once cured, forms a firmly adhering primer film. When an addition-curing silicone rubber is subsequently applied to the primed substrate and vulcanised, a strong, lasting bond is created between the silicone rubber and the substrate. The two components are mixed in a 1:1 ratio by weight, have an active substance content of approximately 20 per cent by weight and a pot life of 2 to 3 days at room temperature. Component A is opaque to whitish, component B clear and yellowish. The product is mainly used for bonding addition-curing silicone rubbers to already vulcanised addition-curing rubbers.
Key benefits
- ✓ 1:1 mix ratio by weight → simple, predictable dosing of component A and B without complex weighing steps.
- ✓ Pot life of 2 to 3 days at room temperature → generous working time, extendable to approximately 1 week when refrigerated at 6 °C.
- ✓ Active substance content approximately 20 per cent by weight → thin, even film build-up by brushing, dipping or spraying.
- ✓ Curing for 20 to 60 minutes at 100 to 120 °C → rapid vulcanisation of the primer film in an industrial process.
- ✓ Maximum bond strength after approximately 4 days → post-curing at 70 to 150 °C further improves adhesion.
- ✓ Specifically matched to POWERSIL® XLR® 630/640 → particularly suitable for bonding to vulcanised silicone rubber of the same grade.
Typical applications
- → Surge arresters and high-voltage components
- → Cable accessories and cable joints
- → Insulators
- → Bonding addition-curing WACKER® ELASTOSIL® RTV-2, LSR and R plus
- → Bonding WACKER® POWERSIL® RTV-2 and LSR
- → Improving adhesion between addition-cure silicones and already vulcanised silicone substrates
Processing instructions
- Make sure the surface to be primed is dry and free from grease, oil, wax, dust, rust or other contaminants. Also remove any release agent residues from a previous vulcanisation cycle.
- Clean the surface with a non-polar solvent (for example white spirit, boiling range 80 to 140 °C), followed by a polar solvent such as acetone. Roughen very smooth surfaces by sanding until the gloss disappears and remove any loose particles.
- Homogenise component A and component B separately before use.
- Mix A and B in a 1:1 ratio by weight. The pot life of the mixed product is 2 to 3 days at room temperature, extendable to approximately 1 week at 6 °C.
- Apply the primer in a thin layer by brushing, dipping or spraying.
- Vulcanise the primer film for 20 to 60 minutes at 100 to 120 °C.
- Apply the silicone rubber preferably shortly after heating, and no later than approximately 2 days after priming. Keep the primed surface free from contamination.
- In some cases maximum bond strength is only reached after approximately 4 days. Post-curing the cured rubber at 70 to 150 °C further improves adhesion.
Storage and shelf life
Keep opened containers tightly closed and store them in a cool, dry place. The expiry date is stated on the label for each batch. Storage beyond this date does not automatically mean the product is unusable, but its properties must then be checked for the intended application.
About the manufacturer
Wacker Chemie AG is a global market leader in the development and production of silicones for industrial and technical applications.
Professional support
Unsure about the right surface preparation, vulcanisation temperature or combination with a specific silicone rubber? Our specialists will gladly help you achieve a reliable bond. Feel free to contact us for tailored advice.
Product Properties
- Mix ratio1:1Mixing ratio A : B
- Cure time60minutesTime until full cure
Component Properties
- Color AOpaque to whitishColor of component A
- Color BClear yellowishColor of component B
- Viscosity A4000mPa·sViscosity of component A
- Viscosity B85mPa·sViscosity of component B
- Density A0.77g/cm³Density of component A
- Density B0.73g/cm³Density of component B
Application
- Use caseAdhesion improvement between addition-curing silicones and substratesIntended use
- Cure speedFastHow quickly the material can be demoulded
- Cure conditionHeatCondition under which the material cures
Safety Information
GHS classification: highly flammable liquid and vapour (H225). May be fatal if swallowed and enters the airways (H304). Causes skin irritation (H315) and may cause drowsiness or dizziness (H336). May damage fertility or the unborn child (H360FD, component B). Toxic to aquatic life with long-lasting effects (H411). Component B contains a substance of very high concern (1,2-dimethoxyethane). Recommended personal protective equipment: chemical-resistant gloves (fluororubber or PE/EVOH laminate), tight-fitting safety goggles, protective clothing and, where ventilation is insufficient, respiratory protection with an ABEK filter. Use only in a well-ventilated area, away from ignition sources, and do not eat, drink or smoke while working. Wash hands thoroughly after use. This is a summary. Always consult the full Safety Data Sheet (SDS) for component A and component B for complete hazard information before working with this product.| Safety Pictograms | Safety Data Sheets (SDS) |
|---|---|
GHS hazard pictograms
   
Required protection (ISO 7010)
     |
| Signal Word | H‑code | Hazard Statement | P‑codes | P‑statements |
|---|---|---|---|---|
| Danger | H225 | Highly flammable liquid and vapour | P210 P233 P240 P241 P280 P303+P361+P353 P370+P378 |
|
| Danger | H304 | May be fatal if swallowed and enters airways | P301+P310 P331 P405 P501 |
|
| Warning | H315 | Causes skin irritation | P264 P280 P302+P352 P333+P313 |
|
| Warning | H336 | May cause drowsiness or dizziness | P261 P271 P312 |
|
| Danger | H360 | May damage fertility or the unborn child | P201 P202 P280 P308+P313 P405 P501 |
|
| Warning | H411 | Toxic to aquatic life with long lasting effects | P273 P391 P501 |
|
Frequently asked questions
What is the delivery time for my order?
Orders placed and paid on working days are in most cases shipped the same day. Weekend orders are processed on the next working day.
Indicative delivery times: Netherlands usually within 1 working day, Belgium and Germany typically 1–2 working days, other countries depending on destination and carrier. These are guidelines, not guarantees: peak periods, public holidays or carrier delays can have an effect.
What is the return policy?
You have 30 days to return after receipt. Email info@siliconesandmore.com within 30 days of delivery with your name and order number. The full conditions are in our return policy.
How can I track my order?
As soon as your order has shipped, you'll receive a track & trace code by email. It can take up to 24 hours before the code is active.
I have a problem with my order – how do I reach you?
Contact us via our contact page or email info@siliconesandmore.com. We're happy to help you quickly.
Can I order as a business?
Yes. Apply for a business account; we review your application within 3 working days. After that you order while logged in and pay on invoice, with payment terms of 14 days after delivery.
EU businesses outside the Netherlands with a valid VAT number order with VAT reverse-charged (0%, intra-community supply). The VAT number is stored in your business account; it cannot be added to an order after it has been placed.