How to: Molding a silicone case for the BI1 board with a 3d printed form

Silicone molded BI1

As alternative to the 3d printed form a flexible form made with silicone could improve the handling of the BI1. Some adult toys are made of silicone or at least are coated with silicone. Silicone cases are easy to clean.

We use a 3D printed form where we will fill in the silicone. The form comes in two parts that have to be fixed to one another by tinkering wire. Download the form from Tinkercad or Thingiverse.

The board has to be prepared. Put the USB connector into the board and seal the connector on the board with wax.

Put the wires between battery and board. Fix them with tape.

In addition the board has to be hooked to the form. For this we use a USB connector which is plugged in the USB port of the board. Then the USB connector is fastened to the form.

Use a silicone which will become solid and hard after moulding. This property of silicone is indicated by the shore A value. Silcone with a low value is flexible. We have used silicone with shore A 45.

Instructions:

Print out the 3D form. The surface should be as smooth as possible. Take some tinkering wire and fix the two parts of the form.
Fix LiPo and vibration motor. Put some glue on the board. First secure the cables of the vibration motor on the board. Then put the LiPo above. The cables of the motor are between the LiPO and the board.
Put some plasticine on the switch top. This should prevent the silicone to flow into the switch. After the moulding remove the plasticine.
Put some wax, glue or tape over the holes of the USB port. It is very important that the silicone doesn’t flow into the USB port or between port and connector. If this happens it is hard to unplug the USB connector without destroying the female USB plug on the board. If this happens it is impossible to recharge the battery.
Connect the USB port with a USB cable. Now fix the cable with tinkering wire to the form. Check carefully that the board (and motor) doesn’t touch the form.
Now mix the both components of the silicone. Pour the silicone very slowly into the form. Air bubbles could be problem if you don’t have a vacuum tube to remove the bubbles. Blowing air into the form could help to remove at least some of the bubbles.
When the silicone is solid remove the form. Remove overhanging part. Remove the platicine from the switch. Carefully remove the USB plug – don’t force it. The board could be seriously damaged.