Views: 2 Author: Site Editor Publish Time: 2021-07-30 Origin: Site
An alternative method of applying fiberglass cloth is to place the fabric or tape directly on a surface that has already been coated with wet epoxy. As mentioned, this is not the preferred method, especially with large pieces of cloth, because of the difficulty removing wrinkles or adjusting the position of the cloth as it is being wet out. However, you may come across situations when this method may be useful or necessary.
1. Prepare the surface for epoxy bonding. Pre-fit and trim the cloth to size. Roll the cloth neatly so that it may be conveniently rolled back into position later.
2. Roll a heavy coat of epoxy on the surface.
3. Unroll the glass cloth over the wet epoxy and position it. Surface tension should hold the cloth in position. If you are applying the cloth vertically or overhead, you may want to thicken the epoxy slightly with filler, then wait until it becomes sticky. Work out wrinkles by lifting the edge of the cloth and smoothing from the center with your gloved hand or a squeegee.
4. Apply a second coat of epoxy with a foam roller. Apply enough epoxy to thoroughly wet out the cloth.
5. Remove the excess epoxy with a spreader, using long overlapping strokes. The cloth should appear consistently transparent with a smooth cloth texture.
6. Trim the excess and overlapped cloth after the epoxy has reached its initial cure. The cloth will cut easily with a sharp utility knife. Trim overlapped cloth, if desired, as follows:
a.) Place a metal straightedge on top of and midway between the two overlapped edges. b.) Cut through both layers of cloth with a sharp utility knife. c.) Remove the top-most trimming and then lift the opposite cut edge to remove the overlapped trimming. d.) Re-wet the underside of the raised edge with epoxy and smooth into place. The result should be a near-perfect butt joint, eliminating double cloth thickness. A lapped joint is stronger than a butt joint, so if appearance is not important, you may want to leave the overlap and fair in the unevenness after coating.
7. Coat the surface with more epoxy to fill the weave before the wet-out reaches its final cure stage.
Any remaining irregularities or transitions between cloth and substrate can be faired by using an epoxy/filler fairing compound if the surface is to be painted. Any additional fairing done after the final epoxy coating should receive several additional coats over the faired area.
Note: A third alternative for more experienced users is a variation of both methods. Apply the fabric after a wet-out coat of epoxy has reached an initial cure. Follow the first three steps of the Wet Method, but wait until the epoxy cures dry to the touch before positioning the fabric and continuing with Step 3 of the Dry Method. Apply the fabric before the first coat reaches its final cure phase.