You can buy knees or build them:
If you buy there are a number of different designs and vendors. All of them make knees that are made from molds, a good
amount of time and money were put into these molds. The materials (fiberglass, silicone, latex) are sometimes expensive,
difficult to find and even toxic. Not always the sort of project that a DIY builder can do at home. And purchased knees will
cost between $300 and $500...
Many people instead build their own knees. They start with a sheet of plywood, cut, bevel, sand & paint, and in a
while they have a set of wooden knees. This can actually be a good design as long as they are hollowed out well to save weight.
It is very common for Plasti-dip to be used as a paint, it gives an appearance of a rubber part much like the TV robot appears
To make knees that are not made of wood simply build a wood knee, paint it with Plasti-dip and then... REMOVE the wood!
Some people may ask why get rid of the wood. It really depends on what sort
of Robot you are building. If its just a “stand in the corner and blink lights Robot” then there is no need to
have woodless knees.
But if your Robot will be a costume then someone’s legs will have
to go thru the knees. And less weight is a nice touch. Of course if your Robot will move on its own then weight and Center of Gravity are very important, lighter knees will help.
Its not that difficult to go woodless. Make a wood knee, sand it and finish it smooth, apply a mold release, apply Plasti-dip,
remove Plasti-dip knee. Repeat as necessary.
The idea is to apply the Plasti-dip thick enough so it can be used alone without the wood. Of course there will be one
small problem: to peel the Plasti-dip knee from the wood mold you will have to make a cut. No big deal, make the cut so it
will be hidden by the inside knee hinge. This can be repaired latter with normal liquid Plasti-dip. And since this knee
will not support weight some sort of means will have to be found to fasten the knee to the rest of the structure.
How to do it:
Follow all precautions on the Plasti-dip can. Work in a well ventilated area!
1. Get your wooden knee ready, its surface should be smooth and clean. Apply
mold release evenly!