Introduction

With this Instructable we want to explain the way that we fabricated a toilet seat with a resin and fiberglass mold. This piece is part of a bigger product Detachable Toilet Seat, but for its complexity and work time it deserved a single explanation. During the Instructable will be some references to the other project.

Materials

Foam (PU, insulation foam)
Fiberglass (fine and rough)
Topcoat Polyester (PE)
Polyester resin with the hardener
Metal piece (explained how to manufactur it in ...)

Tools

Brushes
Syringe
Hammer
Knife
Sandpaper

Machines

CNC machine
Miltitool (Bosch)

Step 1: Cad Files

Prepare all the cad files with the desired shape of the seating. Install the right parameters which will be necessary to cut it in the foam with the CNC milling machine. Here we attach the files we used for this (made in Siemens NX, prepared files in protomold), which you can download and modify if this is necessary.

Step 2: Prepare Foam

Take a piece of insulation foam and cut it in the right dimensions. These measures will depend on the CNC milling machine that is going to be used. In our case, we had to divide the foam piece and produce it in 4 parts, as shown in the picture.

Once the machine has finished with all the parts, it is time to place it in a wood base, fix them together and sand it until it doesn’t have imperfections.

Step 3: First Layer

Put a first layer of fine fiberglass with the PE resin in the foam mold with the help of a brush. When it’s totally covered, let it dry. When it has dried, sand the reinforced mold again until it’s totally smooth.

Note: to facilitate the work, cut the fiberglass in strips or pieces that fits in your mold and prepare the polyester resin previously. The preparation of the resin will be done as described on the packaging (in our case, we mixed 2% of hardener of the amount of resin with this one).

Step 4: Topcoat

Put a layer of the Polyester topcoat on the mold and, like in the previous step, make everything smooth, using wet sandpaper.

Step 5: Release Agent for Composites

Put several layers (5-6) of mold release agent for composites, then the mold is ready for the lay-up.

Step 6: Lay-up

For the lay up, start with adding 1 layer of fine fiberglass while dabbing the resin on top of it. When this is dry, add a layer of rough fiberglass and saturate with the PE resin. Make sure that the fiberglass is equitably distributed all around the mold.

Note: to facilitate the work, cut the fiberglass in strips or pieces that fits in your mold and prepare the polyester resin previously. The preparation of the resin will be done as described on the packaging (in our case, we mixed 2% of hardener of the amount of resin with this one).

In the video you can see how we did this step and the next one, recorded in a time-lapse.

Step 7: Metal Pieces

Place the already made welded metal pieces (the producing of this is explained in the instructable Detachable Toilet Seat, as the rest of the process that the seating will follow) in the right place inside the mold and put some more fiberglass layers on the top of the plate, so these will be fixed to the seating. Then, finish the lay-up with a layer of rough fiberglass and, on top of it, a layer of fine fiberglass, always fixing the pieces of fiber with the resin. Let this dry.

Step 8: Separate From the Mold

Separate the fiberglass seating of the foam mold (in our case, the foam didn’t survived and we needed extra tools like a hammer and a knife, to separate it). Clean it and remove all the extra material.