Formaing the plastic

Forming the plastic:

Before the plastic is formed all the edges need to be filed, smoothed off with sandpaper and polished on the polishing machine. The forming of the plastic is the last thing to be done on this project, all the filing, smoothing and polishing needs to be completed and when the plastic is formed the project is complete and nothing else needs to be done.

There is a choice of two different types of plastic, one is thick (6mm perspex) and is difficult to cut and finish and it takes a lot longer to finish and get ready for forming. The other plastic is 3mm high-density polystyrene foam and is easier to shape and prepare for forming.

Forming the 6mm perspex

The images in this section refer to the 6mm perspex. When the perspex is ready for forming it is put into the oven at a temperature of 200 degrees C for 9 minutes. If the perspex is in the oven longer then this time or at a higher temperature it will start to deform and air bubbles will appear on the surface. If this happens there is nothing you can do the fix the problem – BE CAREFUL.

When the perspex is at the correct temperature it is removed and placed into the jig, which is located on the desk, the perspex at this stage is very hot and gloves must be worn. The perspex is then placed on the jig, which is a “G” clamp with a specially made base and either a square or circular centrepiece. The top of the clamp is turned and the centre piece is held firm and not allowed to move, the required shape is then developed. Very little pressure is put onto the clamp. The further you turn the clam the more the perspex will shape, at this stage it is your own personal judgement as to how far the clamp is turned.

The perspex will take about 9 minutes to cool down enough for you the handle and remove from the jig.

Forming the 3mm High Density Foam

All procedures for this plastic are the same, the designing, the cutting the filing and the polishing except it takes a lot shorter time to complete.  The main difference in this plastic is the time it take to form the plastic and to cool it down.  The plastic is placed into the iven at 200 degrees C for 1 minute and is then removed and shaped in the same way as the thicker plastic.  The working time from taking the plastic out of the oven to forming it and letting it cool down is about 2 minutes, so you need to be working quickly.  This plastic if left in the oven for any longer thay 1 minute will melt and be completely useless.