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| Gun tubs and blast
shields. By Stuart Calvert
There are better and possibly easier ways of making circular gun tubs e.g. with a thin walled tube, but I have found this method to work well. As for non circular blast shields etc... I haven't found any other way of making them. The easiest way to cut thin aluminium sheet is to score it in a straight line as you would sheet styrene then carefully bend it back and forth along the score line so it work hardens then breaks. Brass has been tried for this but it is harder to cut, harder to bend, heavier and more expensive. |
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The diameter of the tubs is to be 33mm. I cut a disc from
1.5mm styrene that was 32mm diameter. The height of the tub was taken from
the plan. The length of the aluminium rectangle (circimference of the tub)
is found by 2 x pi x r (where pi = 3.14 and r = radius of tub). I used
15.75 for the radius. The strip of 0.5mm Aluminium sheet was then bent around a slightly smaller cylinder. In this case a piece of 25mm PVC pipe. The object you are bending around needs to be a little smaller than the final diameter to allow for elastic deformation (springing back into it's original shape). The circular aluminiun was then placed over the disc of styrene and then ends held together with masking tape. The gluing was done on waxed baking paper so it wouldn't stick to the working surface. CA glue was applied to the inside only and also to the joint where the ends of the aluminiun butt together. |
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The tubs for the 2 single 20mm mounts were made in a similar way. The length was calculated and the centre of the aluminium marked. The distance between the centres of each circle is 30mm. 15mm each side of the centre were then marked on the aluminium sheet. This is so you know where to start bending the circle. Basically, just keep bending until you have bent 180°. Then hold the aluminium with a pair of fine nose pliers (making sure it's at right angles) and bend the lead piece to 90°. This is then glued to the base. |
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The final setup of the top deck. The funnel and lookout posts come next. In all about 2 hours work. |
| Back to the USS Artemis page to see the finished result. | |
| Back to the Contsruction page and "How To" articles | |
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