How to scratchbuild? This is the cardboard tube from industrial paper towels--chosen because it's much thicker and stiffer than say, the tube from a roll of Bounty. Of course, a small mailing tube would be even better, but I had this one handy.
Here's the tube, cut to length. Easy to do, this step--I simply marked off where the cut was to be, by wrapping a thin strip of Evergreen styrene (.015X.250), making sure it was straight by aligning the edges in the overlap. Then I simply drew a pencil line by this guide. Cutting was simple: Use a single-edge razor blade, and rotate the tube against the cutting edge, and continue doing so until the razor blade cuts through the cardboard, then just pull apart.
At this stage, I've cut pieces of .080" Evergreen sheet styrene, to make the end plugs, just a hair larger than the diameter of the cardboard tubing.
Here, the end plugs are installed, using gap-filling CA. Use this glue generously, as too little will simply soak into the cardboard. To hasten this process, I used Bob Smith CA Accelerator liberally, to set up the CA instantly. Then, it was a simple matter to cut the corners of the square plugs away with a razor saw, finish rounding to match the curve of the cardboard tube with a flat mill bastard file.
Next is to make the hard surface of the tank itself. I used .020" Evergreen sheet styrene, the width cut to half the length of the tank itself. To make the sheet styrene easy to bend around the cardboard, I used the old "curl Xmas ribbon trick", in this case, I bent the sheet stock over the edge of the workbench, and drew it back and forth across that edge, to give it a curl.
First section covered in sheet styrene. Of course, you will ask, what about the seams? Well, tanks like this, before electric arc welding became acceptable, were riveted together, much like a steam boiler. This was done by using overlapping strips and bands of steel, over the top of the tank surface itself. So, any misalignment of the seams, gaps, etc, will be covered with wide flat strip stock.
After studying the first tank I built, I discovered that one end was slightly out-of-round, so I made a new one, in fact, 3 new ones, using the same technique of laying styrene sheet over cardboard tubing.
Here, the installation of rivet detail is about half completed. The .010" band in the foreground has the rivets finished. The middle band has raw rod stock installed, you can see both steps here: First, insert the rod stock (.025" on these tanks) into .028" diameter holes drilled into the bands, then clip them off with a styrene "nipper" to about 3/64". Finally, the third step is to dress them all down to about 1/64" high with a sanding stick, the final step being to polish them to a rounded head by using one of the coarser Micro-Mesh polishing cloths (I used the 2400-grit cloth, with water, and the "pad" of my index finger to do this).
When painted, these will be very convincing rivets!
Edited by Art Anderson, 25 September 2008 - 01:53 PM.