Gernitex

Tips for spread tow fabrics use

Storage

Store your fabrics in a low temperature and low humidity room or wrap them in a polyethylene film. Although carbon fibers are not vulnerable to hot temperatures and humidity, the sizing agent or binder that keep them together is. Moreover, humidity on fiber surface lower the adhesion strength between fibers and matrix.

Spread tow fabric manipulation

A spread tow fabric is woven from spread tow tapes made of parallel fibers maintained together by a sizing agent. A compromise has to be found between dry tape consistency and fabric ease of impregnation. When handling a spread tow fabric, it is important to use a method that causes the lowest possible friction to the carbon fibers. The eraser ends of a pair of pencils are useful to grip and manipulate spread tow tapes.

Impregnation tips

Use of a spray adhesive

Place the fabric on a clean surface. Adjust the tapes if some are misplaced. Once the appearance is okay, use a spray adhesive to immobilize the fibers. Turn the fabric upside down on the mold surface.

OR

Place the fabric onto the mold, adjust the tapes if some are misplaced. Once the appearance is okay, use a spray adhesive to immobilize the fibers.

Some spray adhesives are designed to dissolve in the resin so that it does not interfere with the curing process.

Impregnation through a more friction-resistant fabric during hand lay up

Place the spread tow fabric on the mold surface. Adjust the tapes if some are misplaced. Once the appearance is okay, on top of the fabric, place another layer of more friction resistant fabric such as a non spread tow one e.g. a very light glass fabric, a peel ply etc. Put the resin on the laminate and spread it to impregnate both fabrics

Resin flow control during vacuum infusion

In order to attenuate a displacement of the fibers, it is recommended to limit resin flowing inside the spread tow fabric regarding in-plane directions. The resin should rather comes from the ‘top’, perpendicularly to the fabric. A thick infusion mesh can help.

Tacky gel coat

Place the fabric on a tacky surface such as a gel coat and gently press it to optimize the fibers adherence to the surface.