Vacuum bagging will add more time and money to your laminate but will be well worth it if you need a light weight, high strength part. Vacuum bagging will provide high quality parts. In this segment, we will discuss some of the fittings that are needed for the vacuum bagging process.
The most important part needed when vacuum bagging is a vacuum pump. There are many pumps on the market that vary in price. It is definitely an investment. There are ones made specifically for large applications and ones that are meant for medium and small applications. The pumps have different styles (diaphragm, rotary vane, oil bath, piston etc.), motor horse powers and CFMs (cubic feet per minute). You will need to evaluate your project to see which pump will work best for you.
Vacuum Port/Coupling- Used to connect your bag with vacuum tubing. A small slit is made in the bag so the port can be placed. Sealant tape can be used to seal off any excess gaps that may exist. The connection must be as tight as possible to prevent air leaks. There are ports that come in one and two parts.
Vacuum tubing- Tubing is most often sold by the foot. It is used to connect the bag and port to the vacuum pump. It can be cut to size. Check to make sure the opening in the tubing matches the opening on the port and fittings.
Vacuum gauge- This part is optional but can be very important in your application. It helps you detect if there is an air leak. It also allows you to measure the air pressure at all times. This is good to know not only for the current part but also so you can replicate the process on future parts. A T-attachment should be used with the vacuum gauge if it doesn't already come with one.
Vacuum regulator- Regulate the amount of pressure used on the part. There are many times when you may want less pressure than other times, such as before the laminate has gelled. A full vacuum could cause too much resin to be pulled out. A vacuum regulator usually comes with a vacuum gauge so you don't have to buy one separately.
Hose Barb- This is optional. It can be used to connect the vacuum hose/tubing to the vacuum equipment.
You can also use a resin trap or create your own. Their are several on the market or you could make one out of a sealed jar. You would just need to add fittings to the lid. A relief valve may be necessary as well. You can pick up one from Home Depot.
Vacuum bagging can be really simple or really complicated depending on what you need. Start simple and practice on small parts. You can decide as time goes on if you need some of the extras.