Problem Solver: Vacuum Technology

 The pump is drawing in air.

Oil mist may occur until the pump reaches full vacuum. Check that the system is completely airtight so the pump can reach the final vacuum and the oil mist disappears. Filters can be used to capture mist during pumping.

a. There is a vacuum leak.

b. The pump has no oil.

b. Also check that the pump has enough oil. At rest, the oil should reach halfway up the sight glass, this means almost the entire bottle of oil is in the pump. Without sufficient oil, the pump will not be properly lubricated, which can lead to the pump blades burning. This is not covered by the warranty.

Incorrect pump selection.

The small BILTEC vacuum pumps all reach a deep vacuum of about -0.99 bar. These pumps cannot be adjusted to generate a lower vacuum (less deep). If you need a lower vacuum level, choose a vacuum system with a pressure switch and buffer tank, such as the BILTEC PS9/80.

An alternative is to use mechanical vacuum regulators, which work like a pressure regulator on a compressor and allow you to adjust the vacuum manually.

 The pump has consumed oil.

 Refill the pump by removing the fill cap and adding oil. Ensure the oil level at rest reaches halfway up the sight glass.

Incorrect unit set on the pressure switch.

Press the rightmost button to activate setting mode.

Press the 3rd button to change the unit. This can also be seen on the gauge, the 3 LEDs to the right of the display.

Press the rightmost button again to return to operating mode.

Incorrect combination of settings or buttons pressed.

Reset the pressure switch (see instructions below). Then set it correctly.

a. Vacuum set too high.

b. Leak in the system.

a. The pump can reach a maximum vacuum level of -0.85 bar. Do not set the vacuum higher than -0.85 bar.

b. Check the entire system, including the object being vacuumed, for leaks.

Vacuum leak in the system.

Check the entire system for leaks, including the object being vacuumed.

a. Insufficient vacuum.

b. Resin is too cold.

c. Resin type is harder to degas.

a. Ensure you use a pump with sufficient vacuum level and capacity. Also, check the system for possible leaks.

b. Make sure the resin is warmer. Note: this will shorten the working time.

c. Consider using a different resin. Our RESION UV Epoxy (EP101UV) is excellent for degassing.

a. Choose a more easily degassed resin, e.g. RESION UV Epoxy (EP101UV).

b. Allow some air into the container so the resin settles back down. Then rebuild the vacuum and repeat if necessary. Gently lowering the vacuum chamber onto the table can also help, but make sure no resin spills and the mixing cup remains stable.

 Resin type is harder to degas.

Consider using a different resin. Our RESION UV Epoxy (EP101UV) is suitable for degassing.

Remaining bubbles will implode when the vacuum is broken.

 Degassing takes too long or resin cures too fast.

Choose a slower-curing resin or work faster.

There is a leak somewhere in the system.

Carefully check the entire system for leaks. If necessary, use an airtight base plate for extra protection. Note: plywood is not airtight!

Too little vacuum film has been used.

Create a pleat in the vacuum film at each inside corner. This ensures enough film is available to reach properly into the corners.

The resin cures too quickly.

Laminated without sufficient care.

Work very carefully and apply an excess of resin to the first layer. This creates an upward resin flow that helps carry air bubbles out.

Too little bleeder or too much resin was used.

No perforated release film was used

Too much vacuum pressure.

Use an adjustable vacuum pump such as our vacuum system PS9/80, and set it between –0.45 and –0.55 bar. Combined with perforated release film, this ensures optimal results for wet bagging.

The mould edge is contaminated with resin.

Sealant tape will not adhere to wet resin. First clean the edge with a cloth or bleeder, then use a Cleaning Wipe or baby wipe for optimal adhesion.

Smooth fabrics.

Use spray adhesive for vacuum infusion to keep the fabrics in position.

Too little vacuum film used.

a. The resin cures too fast.

b. The amount in the mixing bucket is too large.

a. Use a resin with a longer pot life and/or work at a lower temperature. For example, use Universal epoxy with slow hardener.

b. At first, the resin is drawn quickly into the laminate, but this process slows down. Ensure the resin buckets are nearly empty by the end of the infusion.

a. No infusion mesh used.

b. Too few runners.

a. Use infusion mesh and appropriate vacuum infusion materials. Very dense carbon UD and glass mat (CSM) can be more difficult to process.

b. Use enough runners and position them close together for optimal performance.

a. Incorrect strategy.

b. Insufficient vacuum.

a. Make sure runners are always laid apart and never towards each other. Also treat inside corners as runners, as resin tends to flow faster there.

b. Ensure an excellent vacuum. A good vacuum solves many problems.

The core material is degassing.

Make sure the core materials are completely dry. Keep the laminate under vacuum for several hours before infusion to compensate for pressure differences in the core. This helps dry the laminate, especially materials like aramid and balsa, which absorb a lot of moisture.