VACUUM FORMING – Project 001


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Project 001 – Canopy For A Honey Bee King II Helicopter

This project was to try a simple project to evaluate vacuum forming with PETG.

The part I chose is the canopy for an Esky Honey Bee King II helicopter.


First, side elevation and end elevation drawings were done.




Side Elevation and End Elevation


The mould is made larger than the final part so that the edge of the part can be cut along a piece of flat material instead of a corner.





A mould is made of each half. Before the outline of the moulds was cut, two alignment posts were place in each block of balsa. Carbon fibre tubes with 5mm inside diameter were embedded in holes and carbon fibre rod with 5mm outside diameter formed the pegs. This allowed the outlines of each mould to be the made the same shape and also to separate the moulds afterwards.


The cutting lines are marked on the mould. This mould will be used for two sizes of canopy. The larger cut out line is for the Honey Bee and the smaller cut out line is for a smaller helicopter.


After the outlines of the mould were cut, the edges were rounded with files and sandpaper to acquire the desired shape. Care was taken to ensure the edges to be joined together were in line and not at an angle.to each other.

A layer of wood filler was put over the surface of the moulds and smoothed off with sand paper.


A few canopies were made from PETG and one finally with HIPS.


Canopy ‘A’ is the original Esky canopy.


Canopy ‘B’ was made from 0.75mm thick PETG. This was thicker than required.


Canopy ‘C’ was made from 0.5mm thick PETG. The windscreen was painted on.


Canopy ‘D’ has a windscreen glued into it. The windscreen was also made from 0.5mm HIPS painted on the inside. A separate mould was made for the windscreen.


Canopy ‘E’ was made from 0.5mm HIPS.


I found that I obtained better results with HIPS for these reasons.

1. HIPS does not require preheating to removed absorbed moisture before it is formed.

2. HIPS is better at forming tighter curves than HIPS. At the tip of the nose, PETG tended to form ‘fillets’ that had to be filed flat. HIPS forms very tight curves without ‘filleting’.

3. Gluing HIPS is easier when Revell glue for plastics is used.



A few more designs were considered.



I like this red one. The alarmed expression seemed appropriate to the way I was flying then.



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