About the Club Member's Area Club Gallery Robot Reference Information Robot Parts For Sale!
    Robot Reference->Construction Tips->Homemade Torso #2  

Homemade Torso #2


By Mike Joyce

I plan to construct a mold from which I can produce accurate one piece fiberglass torsos.  Let me start by saying that this is a difficult project that might be better left to the professionals.  Fiberglass is hazardous and precautions must be taken to ensure fire and health hazards are avoided.

I made a paint & fiberglass booth to work in, note the fan in the bottom right corner, air comes into the basement through an open window, is forced into the booth by the fan and then goes outside through a window inside the booth. The booth is 10'x10'.

After hearing about long term problems of cracking, etc. with torsos constructed of wood, bondo and other materials I decided I would attempt to first create an accurate torso using wood, fiberglass & bondo and then use this torso to construct a fiberglass mold to allow production of one piece fiberglass torsos (the ultimate goal).

Construction of the main torso or "plug" from which the mold will be constructed

The torso plug will be constructed from three main parts:

  1. The Conical tube
  2. The Top Dome
  3. The Bottom Dome

These three parts are separated by two .75" thick rings.

I decided to create three temporary female molds to allow production of the male fiberglass part.  The three fiberglass sections will be connected together by two .75" plywood rings.

The Tube

I cut a piece of sheet metal such that, when curled up it forms a conical tube of the correct dimensions.

Picture of sheet metal before it is cut out.

Picture of sheet metal after it's cut

Frame to hold the sheet metal.

Finished female tube mold,
ready for fiberglass

Removing the mold from the fiberglass.

The raw fiberglass tube

Tube with arm holes & chest
panel cuts, with rings

Another shot of the tube section, arm sockets and chest panel trim still to come

The Top Dome
I make a form from waste sheet rock and plaster.  A sheet metal profile of the dome is cut and attached so that it can rotate in the form to shape the wet plaster to the correct contour.

A picture of the dome profile and rotating assembly

Here's a shot of the female mold for the top dome section

Here it is after the fiberglass has been laid

Here's a shot of the raw top section

The Bottom Dome
I made another form and created a new profile template to shape the female mold for the bottom section.

Here's the bottom section mold, no trim details yet

Another shot of the bottom section

Trim added, ready for fiberglass

Here's the raw completed bottom dome

I decided to paint the bottom mold with a spray gloss enamel to help with the mold release.  On the top one I just greased it up with vasoline and the plaster still stuck to the fiberglass in some places.  Of course it doesn't matter that much as the plaster mold is only used once, but it was messy.

The Arm Sockets

The arm sockets are really difficult!  Here's how I plan to do it.  First cut out the hole in the tube section, then user paper to form the shape of the sides of the socket.  Use this paper template to cut a piece of sheet metal the same size.  Use the sheet metal to form a mold.  Fiberglass this mold and remove it.  Use this (inverse) mold as a master to create two fiberglass sockets.  Install them in the holes and add trim.  Simple eh?!

Here's a shot of the paper template I made

Here's the sheet metal mold ready to create the inverse fiberglass mold

Here's the inverse mold:  I will use it twice to make two arm sockets

Another shot of the inverse mold

Here's the two raw fiberglass sockets with the mold

Here's an close up shot of one of the new sockets

Here's the socket with the Bondo trim added

Adding The Bondo Trim
I used Dave Painter's technique of using foam insulation strips to make the "forms" for the chest area trim.  I then filled the forms with bondo and let cure.  After it sets up, remove the foam and sand the trim to shape.  Remember, since this must be pulled from a mold there will be some "draft", in other words the trim is wider at the base than at the crown.  The original was like this also.

The Pieces Start Coming Together
Here's the plug with a final coat of Duratec sandable fiberglass primer.  (If the primer looks a little rough, it is.  I brush it on fairly heavy to make sure any pinholes, depressions, etc are filled.  When I'm done sanding most of the primer will have been removed.)

The primered torso plug

Another shot of the primered torso plug

Note that I've also added the knob and microphone backplates.  Based on pictures from Michael Davis and my own research using photos and video, I finally decided not to go with the standard flat raised circle.  Instead I think I've come close to duplicating how it really was.  The knob has a ring with a slight depression, the microphone's depression is more pronounced. 

The Ugly Plugling

Here's the finished plug

Another shot of the finished plug

It has been sanded smooth using a multi step process.  80, 120, 220, 320, 400, 600, 1000 and finally 1200 grit sandpaper was used to achieve a glossy smooth finish.  The different colors are green for fiberglass, pink for Bondo, white for glazing compond (to fill small holes) and grey for the Duratec catalyzed primer.  Weird looking, eh!?

12/30/99 That's it for the plug.  About 70 hours, and around $500 dollars later it's done.  Next I will make a mold from this plug.  This plug could be used for a replica as is, once the holes were cut.  But I'm not sure that the wood & bondo would hold up over time without cracks.  Thanks for the support!


Copyright Information Email Me!