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Sometimes I get asked what the best materials are to prototype with. My typical answer is that it depends. So, I wrote down what it depends on. Hopefully this article helps you understand what prototyping materials to use and when.����

5 Things to Consider Before You Start Prototyping

1. Your Testing & Validation Approach

First, it’s important not to get too attached to your first prototype. Often, inventors will hang all of their life’s expectations on the first prototype like a dad at a little league game. The problem with this is that in the effort of creating a prototype, you’ll learn more and become more skilled, so much so that when you look at the end product you’ll be dissatisfied with what was created because it won’t reflect the quality of work that you’re now capable of. 

So, to avoid becoming too emotionally attached to the product concept, you should first create a list of all the biggest unknowns related to the product concept. Once you have this list, ideate ways that these unknowns could be tested. Each of these tests will require some physical manifestation of the product concept to be tested. You should build no more than the minimum required thing to test the product against the first critical unknowns.  

Following this framework allows for a more analytical approach to creating and killing versions of your product idea by understanding the mortality of concepts upfront and the need to test them.  

2. Your Budget

The next thing to consider is your budget. Very few of us have unlimited resources, so we must treat our resources with care. If you follow the process explained above and only build the miminum required to test your idea at each phase, then you’ll naturally be on the right path for not overspending.����

3. Your Audience

Who is the audience for your prototype? This will drastically change the requirements of how you build it. If you plan to show the prototype to a group of users for feedback, you may need a very polished prototype that looks and works like the intent of the final product to get accurate feedback. But you could also get away with a prototype that works correctly even if it looks a little frankensteined, especially if you have an illustrated storyboard that shows what the final product will look like and the ideal user experience.  

Just keep in mind that every time you ask the audience to “imagine” how something will look or work, the opportunities for misunderstanding are compounded. This can be fine and a great way to save effort and money, but after a certain amount of miscommunication, the feedback won’t be useful anymore because you and the audience are no longer talking about the same thing.  

If you intend to show your prototype to an investor, make sure you know what questions that investor is likely to be interested in (they are usually cost-related), and make sure your prototype answers those questions. 

4. Your Skillset

After you’ve gone through the work to understand what questions your prototype must answer, how much you have to spend, and who your audience is, it’s time to look inward and understand what you’re good at. If you have a knack for woodworking and the prototype could just as easily be made of wood rather than steel, obviously you should select the material you’re most comfortable with. When the material and how to work with it isn’t the obstacle, it frees you up to work on the real problems with fewer distractions.  

Additionally, because you started with work to define what the prototype needs to be, you should be better prepared to share that vision with other skilled makers so that the prototype can be made via teamwork. 

5. Flexibility

Finally, plan for flexibility in prototyping. As you create and test your prototype, the flaws will become apparent in the first prototype, and you’ll want the prototype to be as easy as possible to change so that the problems can be addressed.  

A 3D print is a great way to create a prototype, but if you identify that a hole’s position must be changed, you can’t just drill a new hole without harming the integrity of the part. It’s true that the CAD file could be adjusted and then reprinted to address the hole’s position, but this can take time depending on the size of the print. With a steel prototype, the hold could be welded shut and redrilled in a new location over and over.  

Some engineers make their 3D-printed prototypes out of modular parts puzzle-pieced together, allowing them to change out specific high-risk-of-change parts without needing to reprint the entire prototype. 

Pros and Cons of the Most Common Prototyping Materials

After reviewing the above considerations about your prototype needs, you should be well equipped to make decisions about what material(s) to use. As a helpful resource, I’ve put together some thoughts below on the pros and cons of various prototyping materials.����

Material	Pros	Cons
Sketch	– Cheap – Fast	– Requires more imagination from your audience – Can prove out mechanical performance
Cardboard/ Foamboard/ Paperboard	– Cheap -Tools for working with it are easily accessible – Easy to adjust, cut, and glue	– Not structural – Has a lower quality appearance
Wood/Plywood	– Looks good – Higher structural integrity than cardboard (allows for some structural testing) – Can be prepped and painted to look like other materials – Woodworking tools are relatively accessible, as are people with skills to use them – Can relatively easily be reworked as you learn and adjust	– More expensive than some other options – Heavy – Splinters! – Grain direction means that the material is stronger in some axes than others
3D Printing	– Many materials with many different properties are available – Pretty high precision – Changes are simple if you’re proficient in CAD – Work can be done while you sleep!	– Doesn’t match real-world production methods like molding (could create something that’s difficult to recreate at any volume) – Rarely solid fill, so if you want to make a small adjustment (e.g., drilling a new hole), you can’t do it without impacting the strength of the part
Steel	– High strength – Readily available – Very adjustable (can cut and weld steel repeatedly as you adjust) – Fair amount of people who are proficient in steel work – Suppliers can give you accurate parts that match a drawing laser cut or CNC process	– Only adjustable if you have the tools to work on it yourself (otherwise, you’re dependent on supplier timelines)
Aluminum	– Strong – Light – Soft enough to be easily machined or worked on with woodworking tools	– Difficult to weld – Fatigues when bending (Unless your prototype really needs the material properties of aluminum for your learnings, use steel. At least at first it will be easier.)
Fiberglass	– Can make large, strong parts in organic shapes – Easily painted to high finish levels	– Difficult to scale to production in the future – It’s fiberglass. It’s itchy and miserable.

Find the Right Fit for Your Next Prototype

If you’re working on a complex material decision or need help building a prototype that bridges design and manufacturability, my team at �Ӱ���Ƶ Engineering can help. We work alongside clients to test, iterate, and refine, consistently turning great ideas into valuable designs.����

Connect with us here to let us know what you’re working on.