Here are a few vacuum bagging tips I have learned at work that may help with your projects.

1 keep your vacuum bags hydrated. I keep them in a bag with a damp cloth

2 when you are sealing the bag with vacuum tape make sure no glass or carbon threads get on the tape. They will cause a leak by wicking air into your bag

3 As you are sealing the boat, put a pleat into the bag anytime there is a vertical height change. (i.e. the rocker on the hull or the bow and stern)

4. Any con-cave surface is a potential bridging area. You always want to put pleats in the bag at the inflection points of the curve so that as the bag is drawn down the bag is held tight against the part rather than “bridging” across the part. Any bridge is sure to create a void in the laminate or in extreme cases can puncture the bag.

5. A good bag should hold a vacuum after the compressor turns off for 1 min without dropping more than 2 in. HG. Our vacuum bags are kept at 30 inches and we try to get them “dead” so that there is no drop at all.

6. Use bleeder to soak up excess resin. Be careful not to suck resin into your vacuum pump. We us a trap between the part and the pump to prevent this.

7. You don’t need those fittings that go through the bag. We use a pipe fitting whos end is wrapped in breather felt and a couple of wraps of vacuum tape sealed into a pleat to enter the bag.

There are probably 50 more tips but this should get you started. Let me know if you have specific questions. I do 5-10 bagged parts per week in our boat shop.

Regards,

Jack