Which Plastic Goes Where?

Posted: March 8, 2017 in Building & Design
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First things first, we here at Redwood Plastics (the administrators of the Plastichowto blog) are happy to answer your application related questions. That said, we might be able to save some time with your future DIY projects by helping you narrow down what plastics you might need for your application. If you’re still hesitant or have additional questions just ask us. Without further adieu, a list of plastics and where they might fit in to various applications:

UHMW polyethylene:

An incredibly versatile plastic, UHMWPE is the “Swiss army knife” of plastics. It’s good at a lot of things, great at a few things and substandard for a few applications. If you need an impact-zone UHMW works as it’s virtually unbreakable and it also works as synthetic ice (though unlike HDPE, it will dull skate blades). It functions well as light-load bushings (under 500 PSI) but cannot hold tight tolerances (+-) 0.05″ is about the best you’re reasonably going to get. We’ve seen UHMW used as sheaths for bladed objects and cutting boards as well. UHMW has benefits of being inexpensive compared to other industrial grade plastics and is also widely stocked.

Nylon:

Nylon’s main application in DIY applications is as sheaves and bushings. Nylon machines well and can handle 4000PSI in operation, which is why it works so well under load. You do need to be aware if your application is exposed to the sun (and therefore need UV-stabilizer) and if your application is marine. For “wet” applications acetal is recommended as a substitute because nylon will swell. In addition, nylon gets brittle below -10 degrees C.

Acetal:

An excellent all-around plastic, acetal can be substituted for nylon in most applications as it handles a similar load for applications like bushings and sheaves. In addition, acetal is the best engineering plastic to machine. It holds tight tolerances and is excellent for small, complex parts. A popular DIY application for acetal is replacing metal parts in paintball guns.

Tuffkast:

A premium nylon-like material, Tuffkast was designed to overcome the drawbacks of nylon. Tuffkast is better in the cold and absorbs much less moisture than nylon. It can be substituted in most applications the only potential issue is that it is softer than nylon, which may mean reduced wear properties in some applications. Otherwise, it is extremely versatile and would delight most DIY’ers if they only knew it better.

Acrylic/Polycarbonate:

Acrylic and polycarbonate are used where you need a clear plastic. Acrylic is not as strong as polycarbonate but it has better scratch resistance. Both plastics are much stronger than glass. In addition, acrylic resin is naturally UV-stabilized where only special grades for polycarbonate are. Safety glass, windows, canopies and tabletops are DIY applications for these plastics.

Phenolic/Industrial Laminates:

Industrial laminates are a very large family of plastics where different resin systems, substrates, and additives mean there isn’t a “one size fits all” phenolic. For the DIY community phenolics are fairly expensive and difficult to work with as you require dust exhausting systems and masks. Some are glass-filled which means special tooling to work with them. Phenolics can handle a large amount of load, often in excess of 20,000PSI and are primarily used in mechanical applications by the DIY community. So anywhere the plastic’s job is to provide strength, rigidity and form. It’s hard to narrow down specific applications for this – we’ve seen almost everything! But what comes to mind is, for example, replacing the metal collars on a sailboat (which hold the sail masts firm and steady) with phenolic. Remember, unlike metal, phenolics won’t corrode due to salt and water.

There are several other plastics we could talk about but their use by the DIY community would be limited. If you’re interested in discussing your application feel free to contact us.

Rover1

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