Since mass casting methods are only practical for smaller tools, because of factors such as weight, cost, and shrink, epoxy fiberglass layups are much more common to construct larger tools and molds.

We’re going to demonstrate a very basic layup, using our Freeman 705 epoxy surface coat and Freeman 605 laminating resin to construct a simple, rectangular layup on a flat board. The basic principles shown here will apply to nearly all epoxy fiberglass layups, regardless of their size and complexity.

Our board has already been treated with Freeman Wax Release and PVA Mold Release. For proper application procedure, please refer to our other video on this subject.

Applying The Surface Coat layer

We begin with our application of the surface coat directly on our part. We are applying this with a white bristle throwaway brush whose bristles have been cut in half in order to create a stiffer brush. Notice we aren’t applying this like paint, but rather we are flowing it on, creating a layer of material between 1/32 and 1/16 of an inch thick.

These materials do get hot when they cure, so we are careful to avoid large puddles of material.

Normally, you’ll want to apply two surface coat layers to make sure your part is covered with at least 1/16 of an inch of material. This is especially important when you are working on vertical surfaces. Plus, you will want the surface coat layer thick enough in case you need to perform any touch up work later. If a layer of surface coat is too thin this may expose the fiberglass cloth underneath if any repair work needs to be complete on the tool face.

The almost tack-free state

Before applying each additional layer of surface coat, our goal is to reach an almost tack-free state. This is the point where no material comes off on our glove, yet our finger does leave an indentation in the material itself…as shown here.

The reason for this is we’re setting up for the next layer of material. You want the first layer to be hard enough that the second surface coat does not push thru the initial layer, but is not fully cured so good adhesion is obtained between the two layers.

Earlier, we had tested the material and found the epoxy to still be too tacky – notice the material coming off the part and onto the glove.

Applying The First Layer of Fiberglass Cloth and Laminating Resin

Before applying the laminating resin, we cut our fiberglass cloth to the correct width and length using standard scissors.

Of course, we also need to mix our laminating resin. Since this is an uneven ratio material, we followed that procedure. For more information, please refer to our other videos on weighing and mixing materials.

With our surface coat having again reached the almost tack-free state, we are ready to apply the layers of fiberglass cloth and laminating resin.

We are using two brushes. The cut brush will be used to apply the cloth.

And here you see the long brush being used to apply the liquid material. This material is a little thinner than the surface coat and again, we are flowing this on to obtain a uniform wetting of the tool surface.

Finally, we set the first layer of fiberglass cloth over the resin and we use the cut brush to bring the resin through the cloth. We are applying just enough pressure to get it through, but not too much to disturb the surface cost underneath.

Applying Additional layers of Fiberglass Cloth and Laminating Resin

We can apply additional layers of cloth and resin as quickly as we can, noting the gel time of the resin. When we brush out each layer, we are careful not to stretch out the cloth, which could warp our tool.

We can apply up to 12 layers or about 1/4 inch of material onto our part in one session. After 12 layers, we must allow the heat to dissipate before applying another session of up to 12 layers. Otherwise, the excessive heat from the laminating resin may warp our tool.

For additional sessions, we would need to prepare the surface for the first laminating adhesion layer. One way is to wash off the tool as it will feel a little greasy and then sand it a little. Another way is to take cotton flock and sprinkle it over the last layer before we go, then the next morning we would blow off the excess and then start applying the resin.

Demolding

To demold our tool, we are simply wedging a putty knife under the tool and gently lift. Notice the PVA film that we had applied to the board before the surface cost. Most of this film can be peeled off with your fingers and since the PVA is water soluable, you can wash off the rest to finish your tool.

Paste Laminating is a tooling process designed to lessen the considerable time it takes to lay up medium-sized tool without sacrificing strength or stability.

Those who have followed the epoxy laminating system to lay up a dozen or more layers of fiberglass cloth have experienced the biggest drawback of that system, which is time. In this process, you apply a 1/2 inch thick layer of paste laminate material, such as our Freeman 1020, between layers of fiberglass cloth, creating a very strong, yet lightweight tool in much less time.

This project is going to be a three-part mold with curved parting lines. To form the parting lines, we’re using Freeman’s 3/8 inch high temperature sheet wax. We’ve chosen the 266 series high temperature wax instead of our 165 series lower temperature wax because it is much easier to bend and flex by hand. We are adhering the wax strips with Plast-Econ modeling clay.

After sealing the sheet wax with Freeman Wood & Plaster Sealer, we are applying PVA and wax release to the entire part. For proper sealing and releasing procedures, please see our other video on this topic.

The first step of the paste laminating system involves applying two layers of surface coat such as our Freeman 705, with a cut brush. As always, we wait for the material to reach the almost tack-free state before applying additional layers.

The next step is applying three layers of laminating resin and fiberglass cloth, much as you would in a typical epoxy layup. Since we devote an entire video to epoxy laminating systems, we won’t repeat those instructions here.

After three layers, you are now ready for the paste laminate material. We are opening our packages of Freeman 1020 on a plastic covered table. Since each gallon kit will cover about 420 square inches, we know this project will require more than one gallon kit. So we begin by mixing the entire bags together without having to weigh the material. When we require less than one full kit of material, we will weigh the material using 100 parts resin to 33 parts hardener.

This material is easy to mix by hand. The goal is to mix until the material until it reaches a uniform color.

If you mix the paste laminate material too much, it will become very sticky, which will make it more difficult to apply.

Next, using a rolling pin, we roll our material on a plastic-covered piece of wood, which has been specifically built with a half inch clearance in the middle.

With our material now rolled out to a uniform 1/2 inch patty, we cut the material into strips for easier handling and apply the paste to the back of our tool.

Since most projects aren’t exactly rectangular, you may have to cut the material into smaller pieces to fit into small corners and gaps.

Here is our finished application of the paste laminate. We are now ready for our final three layers of fiberglass cloth, beginning with our laminating resin. You do not have to wait until the paste laminate hardens before applying the final layers of fiberglass cloth.

Notice how we are starting at one end of the part and working our way to the other end. This not only allows us to keep track of where we’ve applied our material, but it also helps us recognize which side should reach the almost tack-free state first.

Our first part is now complete and ready to cure overnight. If we had been following the epoxy laminating system, we would still be laying up our maximum of 12 layers of fiberglass cloth per day and then have to finish up the part tomorrow to add the additional layers required to build a strong tool.

Day Two: After 16 to 18 hours, we are ready to create the second part of our mold.

We begin by removing the sheet wax that formed our parting line. Then, using a razor knife, we clean up the edges of our fiberglass layup.

To clean up the clay that was used to attach the sheet wax, we use a fillet shaper tool to scrape the clay and a rag wipe off the remainder.

Next, we attach new pieces of sheet wax to complete the second parting line. Again, we’re using Plast-Econ modeling clay to adhere the wax and our fillet shaper tool to clean off the excess.

After applying the Wood and Plaster Sealer to the sheet wax, we cover the ends of the first part of our mold with masking tape. This is done to prevent the any of the new material from accidentally seeping into the edges of the first part and therefore locking the two parts together.

Finally, we apply our two coats of Wax Release, two coats of PVA and our last layer of wax release. Our wax release will also dissolve some of the excess clay that we hadn’t removed earlier.

The remainder of our paste laminating is exactly as we did the day before, applying two layers of surface coat, three layers of Fiberglass cloth, our 1/2” thick layer of paste laminate, and finally our last three layers of fiberglass cloth.

On the third day, we created our third part just as we did parts one and two and here on the fourth day, our tool is complete and we’re ready to demold. Notice the makeshift stands that we’ve attached to the outside using our Tuf-Fil. This is so we can later turn the tool upside down.

Before we demold, we are drilling holes through the lips of our mold to ensure perfect alignment of our three parts later. We are inserting brass dowels into the holes.

Here we are placing wedges at the parting lines and tapping them with a hammer. Because we followed the proper sealing and releasing procedures, we are able to demold each part cleanly.

Notice the green PVA mold release on our tool, which can be easily peeled off and washed off with a damp rag.

Since we drilled the alignment pins before demolding, we are ensured perfect alighment when reassembling our tool.

Here you see a sideview of the paste laminate. Again, had we created this tool using the epoxy laminating system, it would have taken many more hours, plus an extra three days to create a mold this rigid and strong.

For even less working time, you may forgo the fiberglass layup steps, especially for smaller or less demanding projects. Freeman also offers Freeman 1030, a new lightweight urethane paste material that can be applied with a paddle rather than being rolled out.