some wax remains. I painted one car without getting all the wax off, and the paint wouldn’t stick. One method of removing the wax in- volves soaking in vegetable oil heat- ed to 165° F, followed by a thorough wash with detergent, rinsing, and a long drying period. Bob Hogan and I have found a soak in acetone with toothbrush scrubbing does the trick in one step. We blow the car off with compressed air from an airbrush to finish the job. If a frame is warped, heating in water at 165° F for five minutes, and then pressing it flat should take care of the problem. The plastic melts at 176° F or 80° C. Just be careful of how much heat you use. Shapeways can print using
many different materials. The de- signer, who has considerable ex- perience, has found that Shape- ways’ frosted ultra detail works well for model railroad applica- tions. The plastic is acrylic. We have found ACC and Goo to work well; however, styrene cement does not. Due to the 3D printing process, the acrylic plastic is po- rous — more porous than styrene — so it soaks up paint. Most of the holes for parts like grab irons are pre-drilled on these cars as part of the printing process. I found it necessary to drill out the chain holders with a bit in a pin vise. If it is necessary to drill any holes, this material drills much easier than resin or styrene. One
drawback of the acrylic plastic is that it is brittle. However, if a piece does break, it is easily glued back together using ACC. 3D printing represents an in-
triguing option for small-run parts and kits. The process is dependent on the skill of the de- signer. The designer who we met by chance did an outstanding job. While each finished car costs about 50 percent more than the frame, the results are outstand- ing. Just understand the limita- tions of the process, and you can end up with a great model! A six-truss rod, 44-foot log-
ging flat with detailed log bunks at a price I can afford? Who would have believed it?
Masterful 3D
Printing This beautiful car was printed with a 3D print- er. This type of modeling was the stuff of dreams only a few years ago. Now almost anyone can have this power in their homes!
What is 3D Printing?
Trying to describe 3D print-
ing is like trying to pin down what makes a face beautiful! The defi- nition changes incredibly rapidly. At its most basic level, 3D
printing is a type of additive man- ufacturing. Material is added to a base, building up line by line, to create a 3D object. The material is deposited much the same as an ink jet printer deposits ink on paper. A computer takes a design, slices it up into layers, and sends the information to a robotic-con- trolled machine. This machine then directs a head to deposit the material to create, layer by layer, the original computer design in
three dimensions. A support ma- terial is needed to hold the layers in place while the material hard- ens. When the completed object has hardened, the support ma- terial is removed, revealing the completed object. The ability to resolve detail is determined by a combination of the size of the dots deposited and the properties of the material. More sophisticated machines
use many different materials, in- cluding liquid polymers, hardened by lasers to accomplish the same goal. Support material is used to allow the hardened material to bridge open areas. In the case of Shapeways Ultra Detail plastic, the support material is wax.
The machines currently being
offered for hobbyists use threads of material, fed into a heated head, but without the support material used by industrial 3D printers. If you want to know more, I encourage you to search the In- ternet and be prepared to be overwhelmed! As with any new technology, the field is expand- ing and changing with incredible speed. Shapeways has several videos on its website that will give most people more information than they need. One Internet site that may satisfy your curiosity is:
http://3dprinting.com/what-is-3d- printing.
SEPTEMBER 2015 59
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