Jim Caruso, the owner of Xtreme Kreations, a custom paint shop specializing in show quality restorations, graphics and airbrushing, has used a consumer level 3D printer to recreate a 3/4 scale model replica of a World War II bomb. No, this 3D printed bomb isn’t a threat to national security, illegal to own, or even harmful to pets or little children. Specifically, it is a scaled down replica of a US 100LB AN-M30 General Purpose bomb. These bombs were originally used for blast fragmentation or mining purposes. Fused at the nose, they had a filler that was 50/50 amatol, TNT or Tritonal. They were frequently carried by aircraft during World War II, and today are very hard to come by. Replicas of these historic weapons, today sell for up to $500.
“As a kid, I remember seeing these bombs in most army/navy shops when I would go with my dad,” Caruso tells 3DPrint.com. “At the time, they were a dime a dozen. Now, unfortunately you can’t find one of these anywhere. After searching for a couple years and coming up with nothing, I decided to model one in my CAD software (rhino3d) and 3D print it.”
Caruso did plenty of research which included finding out specifically what each of the individual elements of the bomb were supposed to look like. He also found a spec sheet which provided him with most of the important measurements of the original bomb. In order to 3D print his bomb on his Makergear M2 3D printer, featuring a 8″ x 10″ x 8″ build area, he had to break it down into smaller parts.
“I find that many people design items to print, and if the whole model fits on the [build platform] they print the thing as one piece,” explained Caruso. “I prefer to model things for print in their basic components and assemble them just as the original parts would have been. It makes it easier to post-process, and the final parts are more realistic because they are assembled just as the real ones would be. All the parts in this model are easily printable with no support, except for the detonator fan blades and the 2 lifting eyes. The shaft for the fan blade is a stainless 3/8” rod and the rivets on the model are real.”
The rivets on the bomb are only for decoration, and Caruso tells us that he could have modeled a small bump on the tail fins of the bomb in order to replicate the head of the rivets, but he wanted to make the bomb as realistic looking as possible.
For the assembly and post-processing, all the areas of each printed part, which were to get solvent bonded together with acetone, were masked off. Caruso then brought all the parts into his spray booth and put three heavy coats of automotive urethane primer on them. When this completely dried, he sanded all the parts down to make them extremely smooth, without any layer marks. Then after using the acetone to bond the parts together, it was off to painting them.
“I mixed a nice OD (olive drab) green color in automotive base-coat and let that dry,” Caruso tells us. “I have a large vinyl plotter in my shop, so after laying out the lettering that goes on the bomb body in CorelDRAW, cutting the stenciling was easy. I painted the lettering, got out my airbrush and faux finished the body. Once I got everything looking exactly how I wanted it, I applied 2 coats of a matte automotive clear coat.”
The bomb, which is 3D printed using ABS plastic, measures almost 30″ long. Caruso tells us that he may put the files used for this print up for free download sometime soon.
As for Caruso’s custom paint shop, Xtreme Kreations, it is located in Egg Harbor City, New Jersey, which is literally 20 minutes from my hometown of Somers Point. He has been in business for 15 years, doing everything from detailed murals on motorcycles, to metal work and complete restorations of antique cars. Even though based in a small town in Southern New Jersey, Xtreme Kreations has created many projects which have graced the covers of publications all around the world. It was only a year and a half ago that Caruso decided to add a 3D printer to his shop.
What do you think about this incredibly realistic looking 3D printed replica bomb? Let Jim Caruso know, in the forum thread he created for discussion of this design on 3DPB.com.