Spray up

Keep the machine clean. Keep it clean so you can read the manometers and discover any leakage if it occur. Put a plastic bag over the machine, if anything else will do. Avoid overspray. Test the resin spray in the spray booth into a waste bucket, and the chopper into an cardboard box in a defined area. Don’t do tests on the floor, save the environment.

Calibrate and adjust the output of the machine according to the products to be sprayed. Remember that low pressure, big nozzle and short distance gives the lowest styren emission. Spray resin, with the tips on, into a waste bucket for 30 seconds. Weigh out the sprayed quantity, and adjust the pressure and the seize of the tip to the desired kg/min. A good value is for the 6000 machine about 4 kg/min and for the 8000 about 6 kg/min. Spray fibers into a waste box, calculate the output to kg/min, adjust the air to the chopper to give you the demanded glass content according to the resin amount. Do this calculation and calibration randomly under production, as most of the spray operators heve a tendency to spray too wet (low glass) laminates.

Adjust the angle of the glass ejector so that the fibres can be caught by the resin stream and wetted out on the way to the mould.

If glass is carried on top of the resin it will give uneven glass distribution and will also make the rolling out operation more laboursome.

Be observant so the fibres are not falling through the resin stream (snowing). That results in low glass loadings and contaminates the workshop.

As said before, minimize styren emission. Avoid overspray. As styren evaporates from wet surfaces, every drop of resin adds to the background emission. To minimize overspray use moulds with wide flanges or use temporary frames.
By using a temporary frame, well treated with relise agent, one can spray up close to “net shape” with a minimum of waste and overspray. This method is specially useful for medium and small seize mouldings.