Vacuum Infusion Process by Tim Marquadt
Vacuum Infusion 101 VIP for dummies!

4/21/06 - Tim Marquardt

When building a fairing or other composite part, there are a number of ways to impregnate the fiberglass, carbon fiber or other materials with the liquid resin. Commonly a brush or squeegee is used to evenly distribute the resin and evenly wet out the material before vacuum bagging the part to remove the excess resin and compress the materials. 

The Vacuum Infusion Process (VIP) is a technique that uses vacuum pressure to drive resin into
a laminate. Materials are laid dry into the mold and the vacuum is applied before resin is
introduced. Once a complete vacuum is achieved, resin is literally sucked into the laminate via
carefully placed tubing. 

Benefits of Vacuum Infusion
Better fiber-to-resin ratio. Better than normal vac bagging
Less wasted resin
Very consistent resin usage
Unlimited set-up time; independent of resin gel time!

Potential Pitfalls
Complicated set-up
Easy to ruin a part
Trial and error

VIP Set-up and Equipment

For the purpose of this brochure, we will be focusing on one general set-up idea with the notion
that resin will be infused into a center point in the laminate. From there, resin will be pulled
outward via vacuum pressure. The final arrangement of materials should look something like

General Reminders
Regardless of any particular arrangement of materials, there are a few items that are important to
Be sure to include a Resin trap in the vacuum line between the mold and the vacuum
pump if there is any possibility that resin can enter the vacuum line while still infusing.
Any material that will be later removed (such as surface flow media or spiral tubing)
should be placed on peel ply. Otherwise, it will be infused into the part.

A Common Variation
In the following example, spiral tubing is used for both the resin feed and the vacuum line. Resin
will enter on one side and fill the length of the tubing very quickly. At that point, resin will begin to
flow across the laminate. While this approach is simpler to set up, the resin will need to travel
across a longer distance. Depending on what materials and equipment are used, this distance
becomes a significant factor. However, on the up-side, the inside surface texture of the finished
part will be consistent.

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