The Repro Laminating System
Repro Surface Coat
and
Laminating Resins
are a popular choice among our customers who are making a
medium-sized tool and don’t need the strength of an epoxy.
To demonstrate working with a Repro surface coat and
laminating resin system, we will create a tool based on
this part. The frame is made of pine wood and the entire
part has been treated with one coat of Freeman Wax Release
and one coat of PVA mold release. For proper application
procedure, please refer to our other video on this subject.
Our Repro Surface Coat and Laminating Resin system has
several advantage over using an epoxy, such as the easy 1
to 1 mix ratio, the lower cost, and the shorter gel times
allow an entire tool to be created in 75 minutes, as
opposed to overnight. Also, by using fiberglass strand
instead of cloth, it is easier to fit the tool around
intricate parts.
Applying
Repro Surface Coat
The
Repro Surface Coat
starts out thinner than an epoxy, so we want to start out
by covering the areas of our part with the highest detail
and the corners.
If the viscosity was too thin, such as for applying
material on vertical walls, we would wait a bit and it will
thicken up.
We will be applying two layers of surface coat, so we’re
not as worried about getting everything the first time
around.
We’re not worried about excessive build-up (as in epoxy)
because Repro doesn’t produce a lot of heat.
After three minutes, notice how the liquid is already
thickening up, making it easier to apply to vertical
surfaces.
The gel time is determined by what point the material is so
thick that it will no longer self-level.
The almost tack-free state will occur in about 15-20
minutes, and then we are ready for the second coat.
Again, we started on the areas requiring the highest
detail. We can also apply this layer more liberally.
Apply
Laminating Resin and Fiberglass Strand
With our surface coat again at an almost tack-free state,
we’re mixing up a small amount of our laminating resin.
Then we apply one coat directly on top of the surface coat
to act as an adhesion layer.
Next, we’re ready to mix the
laminating resin
with the fiberglass strand. First, we mix the two sides of
the laminating resin like any other 1:1 ratio liquid
tooling material. Then we pour the mixture into a larger
cup and begin adding the
chopped fiber.
We can make this as wet or dry as we like. The drier you
make it, the lower the resin content, which will lessen
both the heat and the shrinkage. However, we’ll want make
sure these enough resin so it is still sticky.
Here we have our finished “dough-like” material. The top of
our tool is still wet from our adhesion layer as we begin
to apply it everywhere. We work it into the smaller areas
with a paint paddle.
There will be more material used here than with an epoxy
layup, so we can expect a little more shrink, but it is
will more controllable and uses a lot less material than a
mass cast – which is why mass cast parts are usually used
only for smaller parts.
As we progress, it may be difficult to see exactly how
thick our tool is. We want 1/4 to 3/16 of an inch. Notice
how much easier it is to apply this thick of material than
it is if we were using numerous layers of fiberglass cloth
– this is one of the primary advantages of Repro Surface
Coat and Laminating Resin.
As our mixture starts to dry, it is even easier to work
with. We can even form it with our hand.
Demolding
Here we are unscrewing the backside of our mold. Then,
after turning the mold back over, we gently tap four wedges
to begin separating our tool. It is important to lift the
tool evenly. If you lift from an angle, we may create a
negative draft, which we don’t want.
Once the tool is removed, we have to remove the PVA mold
release by dampening a cloth and wiping off the entire
surface of our tool.