Shoki II-otsu 3

6/Feb/2009

back next





Techniques of the "aluminists"

 I asked to some master modelers how to work with aluminum (they are called "the aluminists"). Let me introduce them.

The master who built 1/20 F-86F solid model used 0.3mm non-annealed aluminum. He made female molds from resin and pressed the sheet firmly (with the vise?) the sheet with thick rubber plate. He used normal super glue. He didn't sand and level the surface off after glueing since this firm pressure produced sufficiently accurate shape. The nose intake was cast in white metal to a silicon mold. The gun port panel was nickel silver sheet and gun tubes were soldered for the aluminum sheet couldn't be soldered. He used metal primer for railroad model. Sorry I didn't ask for more details.

Another master used 0.1mm aluminum sheet. He used rubber adhesive. He diluted it with thinner and spread with brush on both the sheet and model. After the surface of glue dried, he put sheet on the model. After gluing, rivets were engraved. The 0.1mm sheet was thin but the surface was almost flat and no dimples appeared.

The other master used 0.3mm annealed aluminum sheet. He engraved rivets on the glass plate before pressing or gluing. After the riveting, the surface was leveled off with stiff column on the glass plate and glued them on because the surfaces of his model featured conicoid shapes almost exclusively.

Thus, there is no almighty method. The A method is the best for X modeler but Y modeler prefers the B method. My method is only one of many methods. Try several approaches and choose one that suits you best.


The wing again



The left upper surface was finished. I could not avoide dimples, orz. But I did not correct them.
The rivet lines were not parallel.

I had to correct them. The panel was removed.
The new panel was installed.

I engraved rivets again. I could manage to keep them parallel. I made a mistake at the rivet line of upper portion of the flap. So please don't copy them.
The wing and fuselage were glued together.



The connection of fuselage and wing



After gluing the wing to fuselage, the last aluminum was glued.
The aluminum was glued on the flap.

Sorry, I didn't know the exact rivet pattern in this area.
Each trailing edge of the upper wing and flap were sanded to sharp edge.



convex rivets

 The 0.1mm annealed aluminum sheet was used. The sheet was become level off on the hard and level plate with metal column. The surface was scratched with 600-grit sandpaper. The etching saw was pushed from the back side on the cutting mat. Then I pressed the rivets with #3 beading tool from the front side. After that, the panel was cut out with scissors and glued onto the wing. At the same time, 0.1mm aluminum sheets were put on for the wing machinegun access panel and the base of the wing connection bolts cover.



These were tools to make convex rivets.
I was very satisfied with the result however I'm not sure about the pattern accuracy, sorry.



Notes

 I'd like to address some frequently asked questions:

Q: Did you sand down the model surfaces to compensate for the thickness of aluminum sheet?

  • No. Additional 0.5mm doesn't affect the overall image of the model. Model accuracy in general is sometimes questionable to begin with. The kit can be undersized 0.5mm in comparison to the actual outlines. But the cowling intake for example will benefit from modification to the more accurate shape. It's also recommended to sand 0.5mm off the horizontal and vertical stabilizers.
Q: How did you approach the spinner?

  • It's very difficult to form aluminum sheet onto the spinner. Shoki's spinner was painted red brown so the spinner on my model is the plastic part from the kit. If you want the metal spinner, you can either sand the aluminum rod or cast it in white metal.
Q: Did you cut the aluminum sheet before pressing or the other way around?

  • I cut the rough shape first and pressed in on kit's surface then trimmed it as necessary, press it again and made fine adjustments to achieve the exact shape.
Other notes

  • One of the measures to eliminate dimples may be to apply thicker aluminum sheet (for example 0.3mm).

  • Too much annealing causes the decrease of surface sheen.

  • 5 minute type epoxy glue could be a good option.


The horizontal fin

 The last aluminum. The leading edge of the horizontal stabilizer was sanded to the sharp edge. The elevator was not cut from it, the plastic sheet was added to eliminate the step between it's leading edge and the aluminum sheet surface.



The plastic sheet was glued on the elevator and the surface was sanded.
Rivets and the hinge line were engraved.



The landing gear cover

 There were several variants of the gear cover. The very early experimental type had the lower portion hinged and was folded out when extended. There were another two variants. One was flat on the inside and the other one had the ribs on the inside. The former type was seen on model I or II-kou, and the latter on II-otsu and II-hei.

The color of the gear cover inside was as follows. The rib type was natural metal including small upper gear leg cover. Flat type cover insides were typically painted Aotake, it's not confirmed if this happened all the time. The gear legs and wheel discs were natural metal. The wheel wells and the inside of the crescent-shaped wheel cover were painted Aotake throughout all sub-types.

The non-annealed 0.3mm aluminum sheet was used. The sheet was cut, pressed to level, sanded with the 600-grit sandpaper and rivets were engraved. Ribs were cut from the 0.5mm plastic plate. The contact surface of the upper fringe rib was very small, so 0.3mm plastic plate was used as a guide.

The 0.3mm plastic plate also worked for the connection between the gear leg and cover. Of course the gear leg had to be sanded down to compensate for the thickness of the plastic plate.



The ribs on the inside were the feature of model II-otsu and II-hei.
This is the original kit part. This flat type was suitable for II-kow or I.

There was some doubt about rivet lines pattern on the cover.
The gear leg was sanded down to compensate for the thickness of the cover. This kind of adjustments were necessary for the scale appearance of the model.



The propeller

 Shoki propeller blades were rather wide comparing with other Japanese fighters. And the shape of the blade was unique, i.e. the maximum width was a little outside at the middle of the blade and the tip was thin and sharp. The max width was 5.5 or 6.0mm in 1:48 scale calculating from photos of the actual A/C. Kit blades are 5mm wide and look inaccurate. I replaced them with paddle blades from 1/48 Tamiya Mosquito kit sanded to the correct shape.



The blades modified using Tamiya Mosquito parts. Original kit blade is on the right.
The shape of the kit's spinner is perfect. But new 1/32 kit is not good.



Detail aluminum work

 Initially I was going to carve the oil cooler from the solid aluminum block or rod. But it would be tired so again I used the aluminum sheet.



Oil cooler parts were too small to be formed into the aluminum sheet directly so they were glued on the base (another fuselage in this case) and then the sheet was pressed.
The aluminum sheet well represents the thin fringe of the headrest.

The wheel cover was from the 0.3mm non-annealed aluminum sheet. The inside was the 0.3mm plastic sheet.
The small upper gear cover was also from the 0.3mm non-annealed aluminum sheet. The 0.2mm aluminum sheet was bent and glued on the inside.



The landing gear

 Kit's landing gear parts were under-scaled in the upper portion. They were replaced with parts from Hasegawa Zero. The attachment tapes on the landing gear legs were cut from 0.14mm plastic sheet. The tape end was glued on the gear leg first, then winded and tensed, finally glued using thin liquid cement.



The kit parts are on the right. The upper portion was under-scaled. Hasegawa Zero parts are on the left. The cut was made above the oleo strut.
This is the modified landing gear. The torque links come from the kit but were thinned down. The rubber (or leather) covers of the oleo struts were engraved with the etching saw.



The bolts cover



The wing attachment bolts cover and aileron actuator covers were shaped from the 2mm aluminum rod.
The fringe from the thin plastic sheet was added to the side walls in the wheel wells.










back next





HOME