up where we left off from making our own rock climbing hand hold
molds, we'll now walk you through how to cast them. We have two
different types of molds, first the a standard mold with a silicone
stem and secondly a mold where we use the actual bolt to act
as the stem to our hold.
you are going to use a bolt for the stem it is very important
that you mold release the bolt. Alumilite's casting resins
will bond to metal unless it is mold released. We use Stoner
Urethane Mold Release which works exceptionally well for
making sure the bolt releases from the casting.
the bolt back into the stem hole after it has been sprayed
with mold release.
next step is to mix Alumilite casting resin. The mix ratios
of most of our resins are 1:1 by weight or by volume. Mix the
resins thoroughly until no swirls are left in the mix container.
The resins are non toxic and very easy to use. They mix and
pour like water making them extremely user friendly. Mix the
resin thoroughly for 20-30 seconds.
the resin is mixed thoroughly, pour the resin into your molds.
On the right you can see the mold that is using a silicone
stem and the mold on the left has the bolt as the stem.
resins will change color as the materials cure. This is at
the 90 second point with the Alumilite Regular. The resins
go from a translucent coffee color to an opaque tan color (natural
color with no dye added - obviously if you add dye, the before
and after cure colors will change).
after the resin changes color, remove the bolt with a pair
of vice grips or pliers. I would recommend doing this within
a minute or two of the resin changing color. If you wait too
long, you will have to unscrew the bolt.
another minute or two, flex the mold, and remove your first
hold. You can see there is a slight bit of light green picked
up in the hold. The light green is the foam from the original
foam hold. You will only pick up a slight amount of foam in
your first couple holds. The foam that is being picked up is
solely due to the silicone grabbing hold and encapsulating
some of the foam when it was seeping into all the pores and
texture of the foam original. When you pour the resin into
the mold, it bonds and picks up the foam and pulls it out of
the mold. If you are looking to make more of the same hold
in the future, take your first clean casting and put it in
a shoe box to be used for your master the next time you need
to make a mold.
you can see the original hold castings (tan with slight green
areas) along side of two more colored castings (one green and
one blue) made out of the new mold. So now you can design and
make your very own rock climbing hand holds. Both mold methods
work exceptionally well. If you are looking to do long term
production runs of holds, you may want to consider using the
bolt method. If you are just starting out and are looking to
experiment with making your own holds or just want to make
enough to fill a wall or two, I would definitely recommend
the easier method of simply pouring the rubber around the original
and using a silicone stem.
How to make
the Mold for this piece >