Vacuumed Resin Infused

The Vacuum Resin Infusion Process (VRI) 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. This process is aided by an assortment of supplies and materials.

HAND LAY-UP, reinforcements are laid into a mold and manually wet out using brushes, rollers, or through other means. An improvement on that method is to use a vacuum bag to suck excess resin out of the laminate.

VACUUM BAGGING greatly improves the fiber-to-resin ratio, and results in a stronger and lighter product as VRI requires experience in this area and uses many of the same principles.

VACUUM INFUSION builds upon these principles, providing further improvements to the lamination process.


Vacuum infusion provides a number of improvements over traditionally vacuum bagged parts.

These benefits include:

Better fiber-to-resin ratio

Less wasted resin

Very consistent resin usage

Unlimited set-up time



Vacuumed Resin infused construction is used in the making of all our Bullet Boat Hulls

VRI offers a better fiber-to-resin ratio than vacuum bagging. A typical hand lay-up usually results in excess of 100% fabric weight by resin. Resin alone is very brittle, so any excess will actually weaken the part. Vacuum bagging can reduce this number significantly; however, it is still not ideal and can lead to additional problems.

While vacuum bagging certainly improves on the hand lay-up, there is still a hand lay-up involved. Because of this, the laminate will always begin in an over saturated state. Vacuum pressure will remove much of the excess resin, but the amount removed still depends on a variety of variables including reinforcement, resin, time factors, and others.

Vacuum infusion takes a different approach, in that a vacuum is drawn while the materials are still dry. From that point, resin is infused using vacuum pressure. Rather than starting with excess and drawing resin out, VRI starts with none and pushes resin in. Ideally, any excess resin that is introduced will eventually be sucked out into the vacuum line. As a result, only the minimum amount of resin is introduced. This lowers weight, increases strength, and maximizes the properties of fiber and resin. Parts constructed using VRI can approach prepreg levels of resin content.

Due to the nature of VRI, resin usage becomes very predictable. While a standard lay-up varies in resin content due to the human variable, VRI is remarkably consistent. Even when creating a large product, resin usage will be predictably similar upon repeated attempts.

Click here to see more on the infusion process!