Hand Lay Up

The largest number of reinforced plastics composite products are produced by the hand lay-up process. A few examples of this processes uses are: boats, portable toilets, picnic tables, car bodies, diesel truck cabs, hard shell truck bed covers and air craft skins and interiors. The hand lay-up process is labour intensive plus the plastic resins produce toxic fumes requiring well ventilated facilities and protective equipment for workers.

Below you can find an instruction of production of boats using hand lay-up process:

Hand Lay Up Application Process
Basalt Fiber Tech Hand Lay Up Application Process©2015 - Designed by Lucas Sant'Anna
  • 1Preparing the mould: Remove any dust and dirt from mould. If mould is of plaster, wood, or new fiberglass, apply soft wax and buff with soft towel. Spray or brush with PVA, parting compound and allow to dry.
  • 2 Applying the gel-coat: If gel-coat is to be brushed on, allow first coat to cure and then apply the second coat to make sure there are no light spots. If gel-coat is to be sprayed on with a gel-coat gun, spray up to a thickness of .015" to 020".
  • 3 Lay-up skin coat: Brush catalysed resin over gel-coat, then apply the mat and reinforcing fabrics. Resin-rich areas weaken part where rollers will not reach, brushes must be used.
  • 4 Resin Finalization Work with roller adding more resin where necessary until all white areas in mat fibers have disappeared and all air bubbles have escaped.
  • 5 Trim: Trim edges and make sure there is no resin bridging the line between the mould and the part. Sand this edge where necessary. Continue separation by pulling and flexing.
  • 6 The Final Product is now painted and completed with accessories.

The hand lay-up process produces parts from an open fiber reinforced mould. The mould surface is treated with several layers of release wax and then spray coated with a pigmented polyester resin called a gel coat. The surface of the mould will be duplicated by the gel coat. Over the gel coat, Basfiber® is layered. Each layer is saturated with polyester resin that is specifically formulated to cure at room temperature. The polyester resin must be catalysed 2% by weight. The catalyst is a toxic and corrosive peroxide. Each Basfiber® layer is pressed by hand with rollers to work the polyester resin into the Basfiber®. Three to nine layers are added and allowed to cure depending on the desire strength of the part. Once the polyester is cured, the part is removed from the mould. The part requires trimming and post mould surface preparation. In the production of a high performance airplane, both carbon fiber and epoxy plastic are used.

Hand lay-up parts can consist of any size or configuration. Moreover, the process does not require any special tools. Parts can be easily fabricated as a weekend backyard project. Moulds can be easily modified, cut into part for prefabrication and applied to create various surface textures. The rigid properties of the final product require that under cuts and straight wall be eliminated. Any openings must be machined in post moulding operations. All corners must have somewhat large radius. The structure is often stiffened with the additions of honeycomb, balsa or rigid foam blocks.