TecTopics: CAV-PRIME Best Practices

For a faster, more efficient way to apply primer for various EPDM and TPO pressure-sensitive products, we recommend CAV-PRIME™, a revolutionary system that features membrane primers packaged in a pressurized cylinder. Compared to the conventional method of applying primer from a 1-gallon can, CAV-PRIME provides increased coverage rates, increased shelf life, eliminates spills from kicked over cans on the roof, reduces waste of primer curing in a pail that has been improperly sealed, and decreases prep time for pressure-sensitive products.

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Primer Application

1. See each primer’s individual Product Data Sheet for application and precautions.
2. Adjust the spray gun stop nut and trigger lock to half throttle.
3. Spray a small puddle of primer onto the surface to be primed. “Wet out” the roller cover with the primer.
4. Begin the primer application by triggering the gun and rolling the assembled apparatus on the membrane at a walking speed that allows you to maintain a controlled and straight line. A back-and-forth action may be necessary depending on how wide the primer needs to be applied. Trigger the gun as needed to keep the roller cover wet with primer. Continue to apply the primer, making sure that there will be no dry edges once the pressure-sensitive tape product is in place.
5. Any time the spray gun is idle the trigger lock should be engaged.
6. The tank valve should remain open until the contents in the tank are completely used or when the hose is to be flushed with cleaner.

Storage and Cleaning

1. Store cylinders in a protected, conditioned space with temperatures maintained between 70°F (21°C) and 100°F (38°C). Do not store or heat cylinders where temperatures reach 110°F or higher. Contents are flammable.
2. Semi daily use of the primer will not require the tank valve to be closed between uses. The tank valve should remain open and the system pressurized until you are ready to clean and flush the system. Keeping the gun, tip and hose clean is important for long term performance. Flush the gun and hose with CAV-PRIME Low-VOC Hose & Gun Cleaner if the equipment is going to be idle for more than a few days.
3. To clean the gun and hose, close the tank valve on the primer cylinder. Relieve hose and gun pressure by triggering the gun into a waste receptacle.
4. When the pressure is relieved, remove the hose from the tank using a 9⁄16" open end wrench or an adjustable wrench. Thread the hose onto the CAV-PRIME Hose and Gun Cleaner cylinder and tighten the hose with the wrench.
5. Open the valve on the CAV-PRIME Cleaner canister and begin flushing the primer out of the gun and hose with the cleaner. The primer is flushed from the gun and hose when a light fan pattern is formed and the spray is completely clear.
6. Store the gun and hose as is or disconnect it from the cleaner after closing the cylinder valve and removing relieving pressure.

NOTE: Only use CAV-PRIME Low-VOC Cleaner for cleaning the CAV-PRIME gun and hose. Never use Low-VOC UN-TACK or PVC UN-TACK™. Do not interchange cleaners as other cleaners will react adversely with the primers, rendering the spray gun and hose unusable.

General Tips and Tricks

• Ideal jobsite storage temperatures and cylinder performance are between 70°F (21°C) and 90°F (38°C).
• To keep cylinders warm in cold weather, use a hot box or heated blanket where temperature can be regulated and does not reach above 100°F. Do not use standard heat bands as they do not have temperature controls and can overheat the cylinders.
• When using the backpack, the 6' material hose works best to prevent excess hose from getting in the way during application.
• Regulate primer flow through gun by adjusting stop nut/trigger lock to approximately half throttle. This will reduce splashing of the primer as it is being sprayed onto the membrane.
• Position the CAV-PRIME applicator attachment clamps so that nozzle of the spray gun is just above the roller cover (approx. 2-3" away) so that it is close to the roof surface and spraying in front of the roller while walking forward.

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For more information, check out the following resources:

CAV-PRIME Assembly and Application Instructions
CAV-PRIME Low-VOC EPDM and TPO Primer PDS
CAV-PRIME Sure-Seal HP-250 Primer PDS
CAV-PRIME Accessories PDS
CAV-PRIME Video
CAV-PRIME Setup Video