5 Axis Filament Winder

Filament winding is a process that can be used to create round fiberglass shapes with exceptional strength characteristics.  Used for piping, tubing, and tanks, filament winding is normally an automated process that has computer-controlled equipment to place glass and resin around a mandrel- the piece that functions as the mold.

There are many variables that can be modified for filament winding, and these will affect the strength characteristics of the finished piece.  The angle of the glass, number of passes (thickness), use of glass mat, and type of resin will affect the finished product strength characteristics.

I found a short video that demonstrates the equipment and the process.

As you can see, the glass is applied in a consistent manner across the part, allowing for uniform strength characteristics.  As you can see, this is yet another process that the composites industry uses to create useful products with advantages over those of competitors.

Vacuum Bagging Video

Vacuum bagging is a process that requires unique materials and processes, but can be simple to operation in an ongoing basis.

There are many advantages to vacuum bag molding, a few of which include:

• Improved resin/glass ratio
• More consistency across the laminate and part -to -part as compared to open layup
• Containment of air emissions from the resins

As compared to hand layup and chop layup, there are a few disadvantages, including

• Higher consumable material cost
• Higher capital equipment cost
• Difficulty with superior surface finish

Some parts are more suitable for vacuum bag molding than others.  It also depends upon which process it is being compared with.

Vacuum bag molding requires an extremely tight seal between the mold and the bag.  Molds with multiple pieces or holes for inserts can be difficult to complete a seal.

Parts that are overly large and complex can present challenges with placing resin and reinforcement before the cure cycle starts.  The bag must be completely sealed and under full vacuum before the curing cycle of the resin begins.

The basic premise of vacuum bag molding is that the air is removed from the bag, allowing the atmosphere (air on the outside of the bag) to push the bag onto the part on the mold, compressing the layers of resin and reinforcement.  Many misinterpret the process as “sucking the extra resin out.”  We are merely allowing the laminate to be compressed by the weight of the air above us in the atmosphere to consolidate it before cure.  The excess resin is usually absorbed by extra layers of sacrificial material inside the bag.

Moldless Car Body

Building a custom car body with fiberglass can be achieved without using a mold! This will be a truly custom, unique vehicle. It will take lots of planning and hands-on work, but is very possible as shown in these YouTube videos.

There of course are several ways to go about building a basic structure to use for the basic shape.  This video gave lots of good ideas and examples of materials that are relatively inexpensive.

The second part of the video shows some of the actual fiberglass work.  This video of less than eight minutes does not nearly do justice to the amount of work and effort that went into finishing this project!  It was great that the author documented his work and shared with all.  This was a major project that is not for the faint of heart.

He does a very good job explaining the process and materials used in this construction. Every project is unique, however. When discussing the thickness of the fiberglass skin, there are many variables that determine the finished strength. The number of layers to use is dependent on the amount of underlying support structures, part geometry, and required load bearing capacity of the structure. Some areas may need to be stronger for impact resistance and structural loads.

The video author discusses only using epoxy resin with Styrofoam as opposed to polyester resin which will react with the Styrofoam.  Polyester resin can be used if separated from the Styrofoam with an additional layer.  While I have only seen it advertised, there are new spray on primer materials available to cover the Styrofoam and allow polyester resins to be utilized afterward.