DK Pilot 02: Preparing the major parts

Freeing the parts from the rafts:

The acrylic used to print the model is very strong, but can also be brittle.  Printed on tabs that aid assembly are easily broken off if care is not taken.  Fine details are similarly vulnerable.  The best general procedure is to begin by cutting the raft off the vertical support sprues, and then gradually removing the sprues, working towards the model to better see what is being cut.

Freeing the raft from the vertical supports by gently cutting with a razor saw.

Work toward the part with the sprue cutter, removing small sections at a time.

Begin with the hood top, sides, and small end piece:

• The hood top has four downward pointing tabs.

Four downward pointing tabs on hood.

• Some of the sprues attach to the horizontal trim at the top of the side.  Note that there are two rivets at the front of the trim to be careful of when smoothing the trim piece.  These rivets are very faint.

The intersection of the hood and radiator with the side removed.  Notice the two fasteners on the trim, and the recess in the radiator to accommodate the trim attached to the side.  Although the trim is not free standing, recesses are deep enough to make it appear as if it is. 

• Note the chamfer on the trim requires that the side be installed to the hood from below.
• The inner surface of the sides have two tabs on the cab end, and two braces/tabs on the front where the end piece attaches.  

Cab end tabs and interaction of side and hood top tabs.

• The detail at the radiator end of the left side also includes an extremely fine internal support between the vertical post and the adjacent flange that can be knocked out with a file.

Note the small white internal support (side shown in blue, supports in white).

Pointing out the small internal support.

• The end and sides have extremely fine fingers that interlock and form a brace,  Be careful of these, as they contribute to the strength of the assembled unit. 

Note the interaction between the printed on fingers of the end beam (yellow) and sides (green).  Note the shape of the nut-holder for the coupler nut and box.  Also note the indentation in the side just behind the exhaust pipe; this indentation accommodates the cross brace/muffler assembly.

• Take care with the channels extending downward from the end.  The channels fit into the provided brass channel to make the cross piece just above the rail.  A chip to the end of the channel will be hidden by the brass should it occur.  
• When dressing the sides, not the unique profile of the mitre joint at the end, with a small scale thickness section at the end.  Subsequent versions of the model may add more chamfers to the top of these sections in order to simulate scale thickness at the top.

Note the scale thickness section at the end and be careful not to sand this off.

After cleaning these parts the hood and sides will friction fit to one another using the tabs, with the cab side of the assembly lining up.  Before beginning assembly, prepare the cab.

Preparing the Cab:

• The cab is provided as one piece.  Supports attach to both flat surfaces and to rivets.  Using rivets to accommodate supports minimizes clean up of scars on the surface. The underlying rivet can be dressed with fine sandpaper after sprue removal.  Better to cut the sprue high, and sand to the rivet.  Where supports are attached to smooth surface, they are made to be as obvious as possible.  Smooth surfaces can be dressed with the #17 blade.  Refer to drawings if in doubt of any rivet.

Cab support attachments.

• Internal supports attach just inside openings.  Openings are chamfered so that they appear to have scale thickness.  These attachements are easy to remove if you align the tool with the chamfer.  Take care not to chip the fine edges of the openings.

Attachments, just inside the door.  Note the holes adjacent to the door and side of locomotive where hand grabs attach.

• Use 400 grit paper to round any rivets where attachments were made.
• Use files to clean internal attachments.
• Use 400 grit paper to smooth the curved roof or flat expanses.  Minor diagonal lines from the printing process generally fill with primer.  Touching up sanding after primer will take care of any issues, extensive pre-sanding is not necessary.