Let's Play With Fiberglass

by Steve Sharp

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Step 7

The piece has been laid up and looks good. Now peel ply is called for. Take a piece of the dacron cloth and lay it over the last ply. Work the resin/epoxy up through the dacron cloth exactly like working the resin/epoxy through the fiberglass cloth. Don't add any extra resin/epoxy. Smooth the dacron cloth with a squeegee working the excess resin/epoxy out to the edges and off the work piece. Note how smooth the surface is, this is good. Look for any imperfections, bubbles, areas that are not wet out completely, they will be very visible. Once you are happy, set the piece aside to cure, clean up, take the significant other out to dinner, go for a cruz, have a cold one, whatever. Allow the piece to completely cure (12 hours minimum, less if placed in a heated box of some type).

Step 8

Day two. The resin/epoxy has cured, time to see the handiwork. Peel the peel ply off carefully. It should come off very easily resulting in a nice smooth piece with the texture of the dacron cloth. This is the desired surface as if more fiberglass has to be laid to this piece the surface is already to accept the next lay ups. Also, the surface is ready for filler and finishing. If the peel ply isn't used the surface will have the fiberglass cloth weave visible and will require sanding with 36 grit sandpaper to break the smooth glaze from the resin/epoxy.

Step 9

This one is important for locating the part you just made after it's trimmed out. Using a 1/8" drill, drill several holes around the fiberglass lay up and through the solid piece below. Don't drill through the foam as it's going to be discarded. The holes have to be through the fiberglass lay up and the base material. Cleco fasteners will secure the piece on final assembly, the holes are for alignment and will be covered when the piece is finally taped in position.

Step 10

Carefully remove the piece from the duct tape. Slowly work your fingers between the fiberglass and the duct tape, it will release itself from the tape, just be careful. Also, watch those edges, that edge of the lay up is now a skin saw. Gloves help reduce the risk of blood letting.

Step 11

Trim the edges of the lay up with scissors, Wiss type compound tin snips work pretty well also. Allow 1" minimum all around the edge. Trial fit using the Cleco fasteners once trimming is completed. Trim, file, sand, cut as required to get a good fit. Ah, you're lookin' good now!!

Step 12

You now have the completed pieces ready to mount, everything fits as planned. This is critical for a good bond to the base material. Sand the base material and the 1" flange of the piece you just made with 36 grit sandpaper. Break the glaze and get the surface roughed up. If the base has gel coat, sand through it to the fiberglass below. Blow the parts clean with an air hose or vacuum the dust away.

Step 13

Time to get messy again. Put your gloves on again (both pair) and mix up a small amount of resin/epoxy per the directions. Using a rag or paintbrush apply a small amount of the resin/epoxy to the sanded surfaces of both the base surface and the lay up flange. Now mix some flox into the resin/epoxy. You want a "wet" mixture, about the consistency of mushy peanut butter. Smear this mixture onto the 1" flange you left on the lay up. You want enough to allow for some squeeze out. Press the lay up in place, align, and secure with Cleco fasteners. Fender washers (3/16") make nice back ups for the Cleco fasteners and help distribute the load somewhat. When you're happy, remove the excess flox and set the piece aside to cure - 24 hours again.

Step 14

Day three. After the flox has cured trim any excess off, a Dremel works fine here. Also, dress any of the base material away on the back side that isn't flush with the lay up. There should be a fairly smooth blend between the base and the lay up. Sand the 1" flange and 1" out onto the base material with 36 grit, get through that gel coat. Sand both sides as we will be laying up fiberglass tapes to secure everything together in the next step.

Step 15

Now you have something, time to finish and get on to more important things. The piece you made is secured to the base material and it looks pretty good. However, it needs to be securely bonded. Go back to the fiberglass cloth and cut strips about 2" wide and long enough to go completely around the lay up flange. Cut enough for both the inside and the outside. Make sure the cut is along the bias (45 degrees to the fiber directions). Put on the old gloves again, mix up some resin/epoxy and maybe a small batch of resin/epoxy & flox if there are small voids to be filled (as far as that goes microspheres could be used here as well).

Using another paintbrush wet out the sanded areas and lay the 2" strips of fiberglass cloth with the fibers at 45 degrees to the edge of the lay up. If there is a small void throw in some flox you just mixed up, it will all cure together. You want to lap 1" onto the lay up and 1" onto the base material. Two plies should be good. If you have to splice pieces make sure the splices on the bottom tape and the splices on the top tape are not at the same location. When you're happy with the taping lay down some peel ply and work out all of the air bubbles and work out the excess resin/epoxy. Repeat this process for the other side of the piece. Set the piece aside and work on something else (didn't the lawn need to be mowed?).

Step 16

Four days into the project, the resin/epoxy has cured. That's four days of small jobs, maybe eight hours of work total. The lay up you created is now a permanent part of your ride. Sand, fill, and finish as required and you're done. There is one problem, after learning how simple it is to work with fiberglass you will start thinking about other things you can make using these techniques. In reality the work is never done.

Have fun!!!

Steve Sharp (aka. Airdriver)

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