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Having 2 models as reference and few more ideas on some cosmetic and
dimensional changes it was time to build full size plug. There are number of
ways to make a plug or a buck for some and there are numerous reasons to use one
method over the other.
The plug displacement method
One of the earlier methods used among kit car builders and especially one off
builds was to make a plug out of from a foam or a combination of sort of
skeleton then covered with foam and filler or mesh and filler to get the desired
shape of the car resembling of the final product. Once the plug was made it was
prepared to a state where fiber glass was applied and it was used as the final
body shell from which the plug was pulled out. This gave a fairly finished
surface on the inside of the body and rough finish on the surface. The body then was sanded down and filled
in as the fiberglass never had a
smooth surface. This process never produced any sets of molds and was only used
to make one set of body panels. Problem with that is that it only makes a single
set of panels, there is no provision for door jambs, hood or trunk recesses and
would have to be made after the panels are cut out. The method is still used for
one off parts and some builders that do not want to go through making a plug
then pulling molds from it and making panels.
CAD
Running few years ahead. The probably most expensive way is to have the body
designed in CAD as either single full size plug or individual body parts with
all mounting and overlapping and have it CNC machined from a block of material
like foam then coverer the surface with resins and have it machined again to
gain a smooth mirror like finish from which molds can be made. In turn the molds
can be used for making endless number of identical copies of the parts.
Working with CAD files and opting out the CNC machining to reduce cost.
Original CAD 3 dimensional file is sliced where a 2 dimensional cross
section is obtained. The 2 dimensional slices are then used as full size or
scale versions projected to a full version on piece of wood and outline drawn
then cut out to make formers. Those formers are then assembled together with
spacers so that it would resemble full size body. Those formers are then
commonly filled with foam and covered fillers to gain smooth finish. The full
size body is ready it can be used either to make molds or final body shell. One
disadvantage with the formers is that making under cuts or things like door jams
is much harder as some of the formers will be in the way when taking material
away unless the formers where made to have those provisions in them.
Our version, mold from hand made plug.
There was no CAD files to work from so we have approached making the plug
manually by hand. This unfortunately made the process much longer but having a
1:1 scale plug or buck it was much easier to visualize all of the dimensions and
contours.
After the scaled down prototypes where made and decided of general design and
layout criteria, the plug has been made out of wooden formers to hold general
shape of the body that was made of 2 sections. The wooden formers where then claded with
styrofoam sheets which in turn where fastened to the wooden
structure provisioning for wheel arches, windows and rear vent opening.
Once rough shape was established where most of the large amount foam was
removed from the blocks, both sections where joined together and placed on
a grid with center line going through the length of the car. Reason for it was
that the line was used as reference for symmetrical measurements left to right.
The Making of plugs:
General body
Doors
Trunk (front)
Font brake splitter
Light front
Lights fog
Light rear
Interior
Dash (main)
Instrument cluster
Steering Column cover
Blovebox
Kick panel Left / Right
Center tunnel
A Pillar
Upper windshield
B pillar lower
B pillar upper
rear center / window
Door panels
? Headliner
HVAC
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