I was asked to elaborate on the coaling tower on my railroad. Okay, thats enough reason to brag, although most of the story behind it falls more under "lessons-learned".
better view of upper tower...
First, I needed a good prototype. So I started digging through some archives. In "photo album #5", I found the type of coaling tower I wanted. A great big concrete landmark to the logistical needs of a bygone era. (labeled as "coal chute at Centralia Ill.") I printed out a couple of copies of that tower, and some other towers for refrence. Taking a combination of measurments and best guesses, I determined the approximate diminsions. Applying these dimensions in auto-cad, I realized I was about to create a monster. The upper 2/3rds of the tower had to be dramaticly scaled down. Once I had dimensions I was willing to build, I printed out 2 copies of the 4 pages of line drawings. (One for each side of the structure) So far, so good.
Copy one was cut out, and taped together for a mock-up
I laid each printed template out on some corkboard, and put down a sheet of waxed paper over it. I used modeling clay to outline the structure, and pieces of balsa wood for the indentations. Once that was done, I filled the molds with water putty, and hoped for the best.
Unfortunately, it seems waxed paper is a poor choice of backing for a water putty mold. The moisture still seeps through, and causes the paper to warp. This gave the exterior surface an interesting, but unwanted wavy texture.
Once I had all four pieces, it was just a matter of manual labor to bevel down the edges to a 45' angle, and glue them together. (I don't recall how I did that... more waterputty, I think.) The roof and coaling tunnel are balsa wood, while the upper tower is a seperate mold of water putty.
better view of upper tower...
First, I needed a good prototype. So I started digging through some archives. In "photo album #5", I found the type of coaling tower I wanted. A great big concrete landmark to the logistical needs of a bygone era. (labeled as "coal chute at Centralia Ill.") I printed out a couple of copies of that tower, and some other towers for refrence. Taking a combination of measurments and best guesses, I determined the approximate diminsions. Applying these dimensions in auto-cad, I realized I was about to create a monster. The upper 2/3rds of the tower had to be dramaticly scaled down. Once I had dimensions I was willing to build, I printed out 2 copies of the 4 pages of line drawings. (One for each side of the structure) So far, so good.
Copy one was cut out, and taped together for a mock-up
I laid each printed template out on some corkboard, and put down a sheet of waxed paper over it. I used modeling clay to outline the structure, and pieces of balsa wood for the indentations. Once that was done, I filled the molds with water putty, and hoped for the best.
Unfortunately, it seems waxed paper is a poor choice of backing for a water putty mold. The moisture still seeps through, and causes the paper to warp. This gave the exterior surface an interesting, but unwanted wavy texture.
Once I had all four pieces, it was just a matter of manual labor to bevel down the edges to a 45' angle, and glue them together. (I don't recall how I did that... more waterputty, I think.) The roof and coaling tunnel are balsa wood, while the upper tower is a seperate mold of water putty.