subject: How To Make A Plastic Shell For A Robot Beetle [print this page] How To Make A Plastic Shell For A Robot Beetle
You don't need to have access to expensive vacuum molding equipment to make a professional looking body for your robot.
All you need is a large plastic soda bottle, a wooden mold and your kitchen oven.
When a soda bottle gets hot it shrinks, so if you have a wooden mold inside it will shrink around it and form a shell.
1. You will have to find a plastic soda bottle that is longer than the base of your robot. Use the largest one that you can because the bottle will shrink a lot.
2. Make a drawing of the shell shape that you want. Try to keep the design as simple as possible. Nice smooth curves will give the best results, so no spikes.
3. You will need a block of timber to make a mold from. Try to choose nice clear softwood such as a pine. Hardwood is too difficult to shape unless you have some serious woodworking equipment, whereas you can shape the softwood with a few hand tools and a lot less effort. The timber needs to be the same length and width as your robot, the height of the block will depend on your shell design.
4. Trace the outline of the shell onto the six sides of the block. The top view of the shell on the top of the block, the side view on the side, etc.
5. Cut the shape out of the wood block and use a plane or chisel to remove any excess and then smooth the whole shape with sandpaper. Remember that whatever the mold looks like is what the finished shell will look like.
6. Remove the label from the soda bottle and rinse it out with water.
7. Cut the top off at the point where the straight section of the bottle ends, before it curves down to the cap.
8. Put your mold into the bottle and wedge it in place with some pieces of wood so it pushes tight against the bottle on the top and bottom of the mold.
9. Put the bottle onto a flat metal baking tray. Heat up your oven to about 300- 400 F(~230C) and carefully put the tray in.
10. When the plastic gets hot enough it will start to shrink onto the wooden mold. Once it starts it happens pretty quick so keep an eye on it. When it has finished shrinking use some oven mitts to take the tray out of the oven.
REMEMBER IT WILL BE HOT!
11. After the plastic has cooled you can remove the mold and cut away the excess plastic. Leave some extra at the bottom where the shell fits onto the robot to make it easier to attach.
It might take a few attempts but if everything works as planned you now have a great looking molded shell for your robot.
You can either leave it clear or paint the inside black for a great effect.
