We found a great little video on YouTube by user “Make:” which in just three minutes (before credits) gives all sorts of great tips for the DIYer using acrylic in their applications. It starts off with a good point that not everyone knows: acrylic comes in both cast and extruded forms. Yes, they have differences that are important in an application. Yes, there is a difference in cost. Other important tips include how to thermoform, glue, and most importantly – drill, the plastic. Drilling is especially important as the plastic can crack easily, so using lubrication and a soft touch is essential to prevent a wasted part. It will help you answer some questions you didn’t even know to ask prior to diving in: do you have all the materials you need? How are you planning to smooth the edges of the acrylic?

We’ll let the video do the rest of the talking:

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Are you a “DIYer” who makes plastic bearings at home or perhaps looking into doing some? Not sure how to calculate a press fit or a running clearance for your bearings? Fortunately there is a useful tool available from Redwood Plastics available¬† on their website: the machinist chart for plastic bearings found here.

This chart provides valuable information for bearing manufacturing using Redco 750 or Redco nylon bearing materials. While many in the DIY crowd like to use UHMW polyethylene for everything, including bearings, this is not a good bearing material and has large and variable tolerances. The bearing chart is not intended to be used for UHMW bearings. Acetal is similar to nylon and therefore nylon’s values can be substituted directly.

UHMWPE (Ultra-High Molecular Weight Polyethylene) often abbreviated as “UHMW” is one of the most popular and well known industrial plastics. UHMW is seen as a “Jack of All Trades” in many applications while being more available and less expensive than other plastic options. While this is true to a degree, UHMW has limitations that means it will not solve all problems in all situations. In fact, it has some properties which make it deficient and the “DIY” community should keep this in mind.

When to use UHMW:

UHMW excels at taking impact and it is virtually unbreakable, it’s also very slick and the colder the operating temperature is, the better it performs. This is why UHMW is so popular in applications such as toboggans or as rails on sleds: impact + cold + slickness are all important to the application, and it does really well in this application. UHMW is also easy to work with as it drills, saws, and lathes well. It functions as wear pads, sliding blocks, fenders, and in other impact absorbing applications.

When NOT to use UHMW:

The main application we here at Redwood Plastics see UHMW incorrectly used in is bearing applications. UHMW is a poor choice as a bearing for two reasons:

1.) it is difficult to machine to tight tolerances (+-) 0.02″ are the best you can usually hope for and

2.) UHMW has low load bearing capabilities (500-800PSI). In a DIY bearing application nylon or Tuffkast will be superior.

The issue with tolerances is important to hit home: UHMW is not a dimensionally stable material. Not just compared to metals but even compared to many other plastics. We regularly receive drawings and requests for UHMW parts where we cannot quote based off the requested tolerances (or have to get a written waiver for acceptable tolerances). This lack of dimensional stability extends to thermal expansion and contraction which is why it is so hard to guarantee tolerances: if the part is manufactured in 30 degree weather but used in 90 degree heat the dimensions of the UHMW will drastically change!

We hope this points you in the right direction if UHMW is or isn’t right for your project. But if you have questions, or might be wondering what an alternative material could be, please contact us and we’d be glad to help!

FRP wall panels are a great project for the DIY enthusiast. These panels come in 4′ x 8′ or 4′ x 10′ size, usually in white with a “pebble-embossed” surface. They provide wall protection and are designed to be easy to clean (non-porous surfacing and the pebble texture helps with that). But before you start you need to get the project in order. Here are the questions you need to ask yourself:

1.) Do you have the right amount of dividers (j-trims) and inside/outside corners?

This should be common sense but when you buy the panels you need to get the plastic dividers too! J-trims divide the panels that are side-by-side, while the inside and outsider corners link at, you guessed it, the corners. Knowing the room(s) you’re working on and the size of the panels will help you determine what you need.

2.) Do you have the right amount of adhesive?

What we mean here is the special FRP glue. If you’re fixing the panels another way than obviously you don’t need to think about this but most people do use the adhesive and each bucket (4 gallons) covers 200 square feet. We usually recommend you buy a little extra to ensure you can spread the adhesive liberally. It just takes a minute or so of simple math.

3.) Is the surface clean?

Just because FRP wall panels have a special adhesive does not mean it’s so strong that you just slather it on any surface and slap the panels on. Even though the panels can be affixed to a wide variety of surfaces (including concrete!) The surface still needs to be clean. This means “clean, clean” so deburr it or sand it flat than wash the surface clean and let it fully dry before attaching the panels. Failure to do this could mean the panels do adhere properly or even detach. You would think it makes common sense but people don’t always do it.

Asking yourself those three simple questions will go a long way in ensuring your project is a complete success!

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Have you ever heard of “HMW PE 500“? If you have we’d be surprised. Even though the material has been around for years, we at Redwood Plastics, the patron of this blog, have only recently started advertising it. It’s cutting board material. Professional-quality cutting board material, not something for your ordinary kitchen, but something to use in a premium DIY kitchen or outdoor cooking area that you want to show off. UHMW polyethylene gets a lot of love in cutting board applications but as resilient as it is to cutting and wear there’s one problem: it dulls knives. HMW PE 500 is a grade of HDPE plastic which will not dull the blades. In addition, it is FDA and EC compliant. In fact, in addition to being food-safe it actually comes in a variety that is anti-microbial!

It was designed for this purpose.

If you’re wondering why you haven’t heard of this stuff before, well, times have changed in what people expect out of their kitchens. People with the means to do so are building bigger and better kitchen areas indoors and out and expectations are increasing. HMW PE 500 would have previously been kept to the realm of the restaurant and professional chefs only – but nowadays has a role to play in the modern custom kitchen. If you’re just looking for a small cutting board this isn’t your thing: it will be more expensive and it comes in 48″ x 96″ sheets! To utilize this plastic you really do need to have a large cooking area and have space in the budget for this sheet which can be upwards of $250.00 USD, depending on quantity, once freight costs are factored in. But for a DIY application for the cook who wants the optimum material, HMW PE 500 is for you.

If you’re interested in the product please contact Redwood Plastics.¬†

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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

Redco HDPE “Play” Board

Posted: February 21, 2017 in HDPE
Tags: , , , ,

A versatile product to highlight for the DIY community. Most of you will know about HDPE (high-density polyethylene) plastic which is used in countless applications including many products people use in their daily lives. Redco “Play”(ground) board is a specific type of HDPE which adds several benefits over the natural variety of HDPE.

Firstly, the product is available in several colors which itself differentiates it from other commonly available sheet/rod/tube plastics which can be tough to find in colors other than white or black:

play

 

 

In addition, Redco Play offers other benefits over HDPE natural sheet such as:

  • UV-stability (for outdoor applications)
  • Orange peel surface (desirable for some applications where a smooth surface isn’t beneficial)
  • Color is impregnated into the sheet and won’t degrade quickly
  • Impact resistant
  • Wear resistant
  • Easy to cut, drill and fabricate

The product is not stocked at our branches but can usually be brought in within 1-2 weeks. Price before freight costs, taxes, etc is about $12-$15 USD a square foot depending on thickness of sheet. If you have interest in this product for your application and would like to discuss please contact Redwood Plastics.

Tabletop made from green Redco Play.

terrapin