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.
IH Hood Video
Several other posts have documented the work I performed on my 1993 International Truck Hood. I also took some video and recently got it all put together and posted on Youtube. Hopefully you can learn a couple of things.
The SMC hood was ground in preparation of work, and then I used epoxy and fiberglass to complete the work and restore the structure and shape back to original for this truck hood.
Effects of Clear Gelcoat
One of the really cool effects that fiberglass parts can use clear gelcoat. The basic process starts with a properly prepared mold that is waxed and ready for production. The part build begins with a layer of clear gelcoat. Several manufacturers have this product available, and it is sprayed on the same as pigmented gelcoat.
Once the clear gelcoat is tacky, the visible effect is placed down. This can be a wide range of materials and patterns, depending upon the desired outcome. I have a table that has ground granite rock specks.

Granite Table Top
These granite specks are placed down uniformly and consistently to give an acceptable finish. Then some opaque gelcoat is used to finish off the look and help bind it together. After this is cured, the fiberglass buildup is added to the desired strength and structure to give the desired finished part.
This clearcoat can be sanded and buffed much the same way as the opaque gelcoat, though sanding though to the underlying effects would be disastrous.
One of the drawbacks to this style of part comes when an unknown mistake occurs with the detail layer. If contamination or uneven materials have visual problems, the whole part is built before the part is removed from the mold to find these problems. The shape and structure are complete, but surface defects that cannot be repaired relegate these parts to the trash heap. Extreme care must be taken in the detail application stage to prevent this action. Practice and experience with test panels can help minimize these sorts of problems.
Clear gelcoat can provide a very unique and interesting surface medium. A whole new look can be accomplished using existing fiberglass molds, gelcoat spraying equipment, and lamination schedules.
