Molding the TimK Torso Plug.
By MikeJ

TimK spent three years of his spare time making, what is in my opinion, the most symmetrical and perfectly detailed torso plug yet created.  I am very honored that he has allowed me to create a mold for him.

Some differences from past torsos include upper and lower dome profiles that are not constant radius curves but instead follow a more accurate, changing radius.  For example the bottom dome drops down almost vertical at first before curving inwards.  These profiles contribute greatly in creating an accurate looking torso.  Also note that the side vents are slightly wider then previously available torsos in order to duplicate the original, instead of the stunt version.  But the most striking improvement is the sharp trim detail which captures the original look.  That detail had been lost in other versions, probably due to multiple recasting with excessive drafting.  It is plain to see that the huge amount of effort Tim spent reviewing the details and cross checking his work with other expert builders, such as CraigR, has really paid off!

Pre mold work
Tim created a specialized jig that helped him shape the torso as if it were on a large lathe.  When I received the torso the surface was fairly smooth, almost "machined".  I estimate that his surface was roughly the equivalent of sanding at 120 grit.  Since the surface needs to be glossy smooth to create a mold I spent a couple of weeks polishing the torso.  I worked the surface using 220, 400, 800, 1200 and finally 1500 grit sandpaper.  After that I used a polishing paste followed by several coats of mold release wax.  This resulted in the glossy smooth surface that is required.

Tim had created dimples for the chest lights as well as for the power pack jacks.  However, we decided it would be best to mold a smooth surface and use a template to drill the holes.  Note also that no attempt has been made to mold the torso knob and microphone ring flanges because these are best added later to ensure the sharpest detail possible.

Click here for shots of the plug before polishing.
Click here for shots of the polished plug.

Molding the torso

I cleaned up the garage and put down Tyvek sheeting to keep the drips off the floor, etc.  I keep the temp at about 70 degrees while doing the layups.  First, I use clay to form a dam around the chest area.  Note the "keys" or holes pressed into the clay.  This ensures all the mold pieces line up when assembled.  After the clay dam is finished I coated the surface (including the clay) with PVA mold release.  Next the black tooling gel coat is brushed on.  After that cures, two layers of fiberglass are applied using a clear tooling resin.  It is very important that these first layers of glass do not have any bubbles in them.  If it did, the mold surface would break in that area.

Click here for a shot of the chest area work.
Click here for a shot of the left arm socket work.
Click here for a shot of the right arm socket and aft section work.
Click here for a shot of the top dome section work.
Click here for a shot of the bottom dome section work.
Click here for a shot of the finished bottom dome.
Click here for shots of the strengthening layers and final trim work.

The torso mold has been removed from the plug at last!  It's in pretty good shape but will need cleaned and waxed before it is ready for use.

Pulling the first torso from the Mold

Well, I finally finished cleaning up the mold and have pulled the first torso.  I had some problems with the trim around the mouth and especially on the bottom dome.  There is very little draft there and on this first pull I broke a lot of the trim off.  I will modify the mold slightly to open up (or widen) the base of the trim.  Hopefully the next one will all come out in one piece!  But even with that problem the part looks real good.  Nice straight sharp edges.

Click here for shots of the first pull.

Click here for more phots and info on the torso.