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Mark Green is re-working his SubTech 1/60 scale ALBACORE into a phase-4 configured boat, the one with the two counter-rotating propellers. In support of the overhaul Mark asked for some spare parts for his old, old two-motor version of the WTC-3.
Several years ago I discontinued production of our 3" diameter SubDriver's. But, now seeing utility to the bigger, thicker Lexan cylinder for this and other kits out there, I started in on an upgrade -- completely new end and internal bulkheads; these items incorporating features and lessons learned over the years.
Below are some shots and text describing the design and master work that goes into one of our SubDriver's:
RenShape discs (blanks) are turned from RenShape pattern-making plastic (a very dense foam product) to the specifications indicated in the shop drawings. The seating face of these bulkhead masters is about .030" bigger in diameter than the inside diameter of the average 3" cylinder -- this to account for tool and part shrinkage. When done right the actual cast resin part will be a tight fit within the cylinder.
Note that the green screw foundations glued atop the blanks were cut from one of our current line of SD internal bulkheads -- I sacrificed two 3.5" internal bulkheads for these parts. So too was lifted the blow-valve and ballast servo seal foundation assemblies. Why re-invent the wheel when you don't have to? These resin parts later glued to the faces of the forward and after ballast bulkhead masters with CA adhesive.
Two motor bulkhead masters -- each comprising two pieces, the motor bulkhead itself and the motor retaining plate that bolts to it -- are being worked up. One, a single-motor unit, the other a two-motor unit. Both featuring a 3:1 reduction gear housed within the body of the bulkhead itself.
Use of the dial-indicator, depth micrometer, surface gauge, lathe, and milling machine insured symmetry and holding of reasonably tight tolerance between drawings and masters.
Fillets between screw foundations and blank discs were achieved with Evercoat filler laid in with a dapping tool. Later the work was cleaned up with knife, files, and sanding tools. All tool marks were filled with Nitro-Stan air-dry touch-up putty cut to a watery consistency with lacquer thinner then applied to the work with a brush. The dried Nitro-Stan was wet sanded with foam backed sanding sticks making the master ready for a check-coat of primer.
Note the various sanding and cutting tools. Food for thought, guys.
Several years ago I discontinued production of our 3" diameter SubDriver's. But, now seeing utility to the bigger, thicker Lexan cylinder for this and other kits out there, I started in on an upgrade -- completely new end and internal bulkheads; these items incorporating features and lessons learned over the years.
Below are some shots and text describing the design and master work that goes into one of our SubDriver's:
RenShape discs (blanks) are turned from RenShape pattern-making plastic (a very dense foam product) to the specifications indicated in the shop drawings. The seating face of these bulkhead masters is about .030" bigger in diameter than the inside diameter of the average 3" cylinder -- this to account for tool and part shrinkage. When done right the actual cast resin part will be a tight fit within the cylinder.
Note that the green screw foundations glued atop the blanks were cut from one of our current line of SD internal bulkheads -- I sacrificed two 3.5" internal bulkheads for these parts. So too was lifted the blow-valve and ballast servo seal foundation assemblies. Why re-invent the wheel when you don't have to? These resin parts later glued to the faces of the forward and after ballast bulkhead masters with CA adhesive.
Two motor bulkhead masters -- each comprising two pieces, the motor bulkhead itself and the motor retaining plate that bolts to it -- are being worked up. One, a single-motor unit, the other a two-motor unit. Both featuring a 3:1 reduction gear housed within the body of the bulkhead itself.
Use of the dial-indicator, depth micrometer, surface gauge, lathe, and milling machine insured symmetry and holding of reasonably tight tolerance between drawings and masters.
Fillets between screw foundations and blank discs were achieved with Evercoat filler laid in with a dapping tool. Later the work was cleaned up with knife, files, and sanding tools. All tool marks were filled with Nitro-Stan air-dry touch-up putty cut to a watery consistency with lacquer thinner then applied to the work with a brush. The dried Nitro-Stan was wet sanded with foam backed sanding sticks making the master ready for a check-coat of primer.
Note the various sanding and cutting tools. Food for thought, guys.
Attached Files
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