Crusader 2 model build
BUILDING THE PLUG
Building a large scale test model from scans created from the original wooden tank test model is a time consuming and labour intensive process even though technology has given us a head start. The scans were used to produce a series of vertical and horizontal cross sections which were laser cut and then mounted on aluminium tubes to create the ‘skeleton’ of the model plug. Each section is then filled with high density foam before being cut back to rough shape with a hot wire. Much sanding is then carried out to take things back to the outer edges of the skeleton. Body filler is then added and cut back until all surfaces are smooth and true. This is followed by four heavy coats of high build primer, flatted with wet and dry using a guide coat then another four coats. This is followed by a guide coat again even though the surface is already like glass. When polished for a final time it will ready for dividing up to take moulds. This has to be repeated for the sponsons.
Here are a series of photographs showing that progress from plans through to almost complete Plug. This is just the first stage. The Plug is used to create the Moulds which in turn will be used to create the final Body Panels for creating the 1:6 scale test model identical in form to the original wooden tank test model.
In the first set of pictures, the scan of the tank test model of Crusader 2 has been used to create cut-outs which have been assembled to build the buck for the model.
With the bones of the buck assembled from the plan, high density foam is then glued in before being trimmed back to the general outline shape with a hot wire. The extremities of the “bone” structure define the shape.
Here, the body filler is added and cut back until all surfaces are smooth and true.
And with the plug for the hull complete, the whole process has to be repeated for the sponsons.
Model builder Len Newton explains part of the process: