# Making detail parts by 3-D printing



## Eric M. (Jan 3, 2008)

I needed a brake cylinder/reservoir for a 1:8 scale flat car that I am building. I mentioned it to a friend of mine who works for a large company that makes video game controllers. He told me that they have a rapid prototyping machine at work that can make ABS plastic models from a computer file. He asked me if I had any reference of a brake cylinder in a smaller scale and I said "sure". I handed him a 20.3 scale Hartford cylinder. A week later he showed up with this:







The new cylinder is BIG-- almost 8" long!







A closer look reveals that the part needs a bit of cleanup but still looks awesome.







The 3-D printer layers an extruded bead of molten ABS plastic on top of the last layer-- layer by layer, like frosting from a pastry bag, to gradually "print" the part. It is hollow but has a totally sealed shell-- with no openings.







A little modellers putty and some sanding and the part will be ready for priming and painting. Regards,


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## Ralph Berg (Jun 2, 2009)

Eric,
That is awesome.
We've discussed 3D printers on another site.
I hope some entrepreneur takes the plunge and buys a 3D printer just for this purpose.
I'd love to do it myself............full of spirit but lacking funds.
The 3D printer can do much more than detail parts. The possibilities are endless.
Ralph


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## Havoc (Jan 2, 2008)

If you can have them at a discount or through the old boys network it is a great way to make parts. Otherwise it's expensive. 

I'd love to do it myself......... 

http://reprap.org/bin/view/Main/WebHome


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## Jack - Freshwater Models (Feb 17, 2008)

Eric, 

I use 3D printed parts as patterns for making molds routinely. For a one off part price is prohibitive but if they are used to make molds from which to make cast parts it's economical. I just got two patterns for a 1:20.3 item. They will be used to make a mold to produce parts. The down side is that really you need to be very CAD proficient and be able to export the virtual part. For the average modeler there are easier ways but if multiples are being made the cost can be spread out. The brake cylinder is done using FDM which is ok but the surface is pretty rough. There are a variety of methods with some better and/or more costly than others. The amazing thing is that you can have parts 3D printed that wouldn't be reasonable to machine or fabricate. 

Happy New Year! 

Jack


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## DTI356 (Jan 3, 2008)

Eric, 

Now that's what I call a friend ! .......I could use a friend like that. 

Your part looks great! 

1/8 scale trains are very cool....I have a set of 1/8 scale caboose trucks I am planning on putting under a caboose I'll make someday.


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