I used a proven method of many R2 builders to product the body. In contrast to many other parts shown here, first a negative mould was manufactured. Building the body should take place after you have held the dome in your hands and measured it accurately. To make sure that the body conforms with the dome, it is advisable to build one half of the body completely, then check the measurements again and build the second half of the body somewhat larger or smaller if necessary. It would be most unfortunate, if there was a 5 mm gap after all the hard work put into production.

 

The basic structure of the negative mould was made of wood fibre boards. This is a very large part and so you should pay particular attention to the right angles.

As a base material I used a 2 mm polystyrene sheet and after I had checked all the measurements several times I drew out the layout on the sheet.

It is much simpler to glue on all the vertical outlines, the strips, onto the polystyrene sheet before installing them into the basic structure. I used 1.5 mm x 1.5 mm polystyrene strips from Evergreen. I glued these thin strips with universal thinners. The strips were put on the appropriate place and painted with a small brush dipped in thinners once along the edge. The liquid thinners is drawn between the parts by a capillary effect. Here the thinners reacts with the materials and "weld" them together. The main advantage of this method is that no adhesive remains at the edges since any surplus thinners evaporates within seconds.

The "clamped" polystyrene sheet with all vertical strips. This polystyrene sheet must not be bonded, otherwise it will not be possible to release it from the mould.

Now all the horizontal strips could be glued on. In order to give a feeling of “depth” on the panels I used 1 mm polystyrene sheets.

The finished negative mould for the back body.

Before the gelcoat is laid on, preliminary tests must be thoroughly carried out in order to find the most suitable release agent. If this is not done the whole effort could have been in vain !!!

Install a polystyrene sheet and a wood board on the bottom and on the top. These covers should be only screwed on and not glued, because this would mean that it could not be released from the mould.

The laminate was made out of three layers: The first and the last layer consists of 80g/m˛ glass filament fabrics and the middle layer of 400g/m˛ glass pile fabric.

I wanted to use this part as a master model for a silicon mould and so I installed two diagonal struts to improve strength. These are not normally necessary.

After the laminate had hardened, I removed the negative mould carefully. Some outlines therefore remain in the laminate (refer to: Coin Returns), which can be removed later without much difficulty. Here it becomes clear that this method only enables one or two bodies to be made, because the negative mould suffers damage with every casting.


The fibreglass-master model should be primed, filled and painted, before a silicon mould is poured off of it. I didn't do this and as a consequence all open air bubbles, which were at the surface of the master model, were cast (see "air bubbles"). This meant that all further parts, which I removed from this silicon mould, had double the number of open air bubbles, namely, those, which develop anyway with hand laminates, plus those, which were stupidly cast by the silicon.

In order to be able to manufacture the silicon mould, I used once again my "rotation-trick", in order to lay on a first thin silicon layer.

After the first thin layer has dried which depending upon temperature and silicon takes around 30 - 60 min, the part was inserted into the prepared casting mould (later to become the supporting mould). This silicon process should be carried out together with a friend, so that the masses of silicon are filled in, before the hardening process has progressed too far.

Particularly with such large, and extremely expensive, silicon moulds the supporting mould must be developed in such a way that a "retaining edge" develops in the silicon mould (see "silicon moulds"). The silicon mould hangs independently in the supporting mould and makes the positive connection for later use.

The result of the whole work: A silicon mould ready for the production of some R2D2 bodies.

After renewed checking of all measurements the whole work began again from the start:

Paint and glue on the vertical outlines.

Clamp and glue on thousand further details.

Careful releasing from mould after laminating.

…. be thankful for another part.

 

Carefully cut out the break-throughs.

The two body parts are only fixed at some places with thickened resin and glass fibre shred. One day later the total surface of the seams are over-laminated.

The basic sub-construction was made of multi-layer sheets.

Now the break-throughs for the legs could be cut out. In addition an opening was created, in order to be able to introduce the completely assembled basic sub-construction.

The body was bonded to the sub-construction predominantly with PU foam.

The dome drive wheel.

If you put the body like a "chicken on a spit", an all-round lacquer finish is easily possible.

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