Paul,

 Last week I manage to take some pictures of the jigs used for making
 identical housings based on this cut off test housing.  These jigs
 with
 positioning dowels and through bolts have evolve to accept casting
 plates for the DEVCON epoxy, or  hardened steel  plates with drill
 inserts to drill the hold down stud holes for the throttle. Ditto a
 plate to drill the  fuel injector bore holes and the injector hold
 down
 plate studs. As of today these jigs  also have  quick release air hose
 connectors for leak testing.

 Pict . 007  The p-port  final step cutter I made installed in the end
 mill. It is set at a 56.3 mm OD.  Works like a champ.  Not shown is
 the
 P-port insert 56 mm OD 50 mm ID  which has O-ring grooves cuts to seal
 on the inner and outer sides of the water chamber.  It of course slips
 into the port hole. No welding needed and is removable, inspectable
 and
 changeable. Held there by the throttle Plate.  Throttle to be fastened
 to the housing by four M5 studs that also hold on the intake manifold.

 Pict, 080. My design of a  low profile low restriction throttle.
 Why?
 In my application slide throttles are cumbersome and won't get me up
 close and personal to the p-port as I would prefer. Hence the throttle
 opening is  over sized  to compensate for the 1.5mm SUS 304
 thickness of
 the throttle plate.  It is 53 mm ID. The  throttle plates (two needed
 and two to screw up trying) are laser cut ellispes, slotted and to be
 TIG spot welded in situ to the slotted 6 mm Stainless 303 shafts.
 Center
  hole is for jig positioning. 303 on shaft is much easier to machine a
 1.5mm slot into while the material  still has good corrosion
 resistance.
  Shafts shown are not  profiled yet for minimal  air resistance in
 WOT.
 Ditto the  throttle plates  but they will be.  One shaft will not
 protrude from the throttle plate.  The other to the central housing
 spring and cam location. Good advise courtesy of  Kinsler. Now looking
 into baked on teflon paint coatings to see if they have any measurable
 merit in lowering air resistance in the intake manifold parts.  It
 does
 on prop blades.

 Bearings are NTN BEAREE a tough fluorcarbon plastic which is harder
 but
 more slippery than Teflon. I believe this is the same material used in
 motorcycle throttles. This material  has been tested on our wind
 generator swing tail rudders for three years in the field.  These
 tests
 are equal to several million  swing cycles with no failures, at least
 not in the bearing.  Earlier tails had to be strengthened as they got
 beat up in the winds.  Google "Airdolpin wind turbine" to see it in
 action.  Now on sale in USA.

 Other updates as they happen.  The next challenge is to cast a near
 perfect finished epoxy face on to a new housing and have it free of
 inclusions.  That requires a liquid AL. DEVECON and application of a
 vibrator.

 Doug in Japan

How about applying vacuum?

Chris Cosman

Hi Chris,

Good idea in theory but the forms would need to be a  tight fit on the
various curved surfaces.  The force of gravity is adequate and the end
of the pour will be on the top edge of the casting which is easy to
level with a hand dremel tool.

 One trick is to pour the liquid down a rod inserted into the cavity.
Then a use a large industrial  vibrator or the type they sell for
shoulder stiffness for a few seconds and any bubble will just pop to the
surface.

Doug in Japan