Silicone Primer Wacker AV (SLM 74300)
The mixture forms a rigid film of silicone resin when exposed to humidity at ambient or elevated temperature and adheres firmly to the substrate. The catalyzed silicone rubber applied to it then forms a tight bond with this resin film during vulcanization. This primer is suitable for all addition silicones (Silicone addition...) variants from our web shop.
Most silicones often do not chemically bond to a surface. Therefore, to promote adhesion, a primer must be used.
Even silicone formulations modified with large amounts of silicone liquid, of the kind commonly used for making pressure pads, develop excellent adhesion to aluminum or plywood carrier plates when SLM 74300 (Primer AV) is used.
This primer works on:
Metals (such as aluminum, lead, iron, steel)
Some plastics (such as PETG, Nylon, acrylic, epoxy, PVC)
CAUTION: The primer has an ignition temperature of 3°C (from 3°C flammable gases are produced). You must therefore be very careful!
To obtain a ready-to-use mixture, mix components A and B in the ratio 2 : 1.
Due to the low viscosity of the components, this can be achieved by simply shaking the closed mixing vessel.
The final mixture has a pot life of about 2 hours. After that time, we cannot guarantee good adhesion.
Therefore, it is important to mix only the amount that can be processed in that time frame. With 1 g of ready-to-use mixture, an area of approx.
100 cm2 of plywood or 500 cm2 of aluminum can be primed.
The mixture of A and B may release small amounts of hydrogen gas. Therefore, never close the mixing container tightly.
Preparation of the substrate
The surfaces to be primed must be dry and free of grease, oil or other contaminants.
The surface should first be cleaned with a non-polar solvent such as mineral spirits (at a boiling range of 80 °C to 140 °C), followed by a polar solvent, preferably acetone.
Loose particles should be removed and very smooth surfaces roughened by grinding.
Application of primer.
The primer is best applied with a brush, although dipping or spraying is also possible. On relatively smooth, non-absorbent surfaces such as aluminum, the primer should be applied as thinly as possible and without air bubbles. On very rough or absorbent surfaces, such as plywood, the coating should be applied quite generously.
Applying the rubber
An advantage over ordinary primers is that the catalyzed silicone rubber can be applied immediately after the primer has been applied. No drying or heating is required.
The catalyzed silicone rubber must be applied to the primer layer no later than after 7 hours, otherwise a decrease in adhesion may occur.
Usually after 6 hours sufficient adhesion has developed to allow the pads to be removed without problems.
Components A and B of SLM 74300 are best stored between 5 °C and 30 °C in the tightly closed original packaging. The "best before" date of each batch is shown on the product label.
Storage after the date indicated on the label does not necessarily mean that the product is no longer usable. In this case, however, the properties required for the intended use should be checked for quality assurance reasons.
Component B of SLM 74300 may develop hydrogen gas or hydrogen-containing oligomers in the presence of certain substances. Please observe the safety data sheet.
The mixture of A and B may also release hydrogen gas. Therefore, do not seal the mixing vessel properly.
H225 Highly flammable liquid and vapour.
H304 May be fatal if swallowed and enters airways.
H315 Causes skin irritation.
H318 Causes serious eye damage.
H336 May cause drowsiness or dizziness.
H361d Suspected of damaging the unborn child.
H373 May cause damage to organs through prolonged or repeated exposure.
H411 Toxic to aquatic life with long lasting effects.
P-Code Precautionary Statements
P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
P233 Keep container tightly closed.
P271 Use only outdoors or in a well-ventilated area.
P280 Wear protective gloves/protective clothing/eye protection.
P273 Avoid release to the environment.
P243 Take action to prevent static discharges.
P301 + P310 IF SWALLOWED: Immediately call a POISON CENTER/ doctor.
P331 Do NOT induce vomiting.
P305 + P351 + P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P310 Immediately call a POISON CENTER/ doctor.
P304 + P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
P312 Call a POISON CENTER/ doctor if you feel unwell.
P302 + P352 IF ON SKIN: Wash with plenty of soap and water.
P332 + P313 If skin irritation occurs: Get medical advice/ attention.
P391 Collect spillage.
P370 + P378 In case of fire: Use extinguishing powder, alcohol-resistant foam or carbon dioxide to extinguish.
P403 + P235 Store in a well-ventilated place. Keep cool.
P501 Dispose of contents/container to waste disposal