Believe it or not one of the most popular “DIY” plastic projects is making bushings. It makes sense as bushings are a part of so many applications and plastics are an excellent bushing material, outperforming metals such as bronze and babbit in many situations. Plastics are easy to machine and usually last much longer than metal in a bushing application. Cast nylon is probably the most popular material for bushings, as it can take loads up to 4,000PSI and is readily available in filled grades to increase wear resistance and low RPM performance (moly-filled nylons) and reduced coefficient of friction or reduced lubrication requirements (oil-filled nylons). Nylon does have three weaknesses: shock/impact, cold, and water. If impact may occur to the bushing, if it’s in an environment -10 degrees Celsius or below, or in a wet (or marine) operational environment then Redco Tuffkast by Redwood Plastics may be an ideal solution for all three problems. It is a bit softer and can handle a little less load but in many DIY applications this will not matter.

Redwood Plastics offers a handy bearing machining guide that not only supplies typical running clearances but gives an honest comparison between nylon and other bearing materials. You can find the PDF Bearing Machining Guide here.

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Attaching black-reprocessed UHMW (ultra-high molecular weight polyethylene) to the bottom of a jet boat is one of the most popular UHMW applications for the “advanced” Do-It-Yourselfer. The UHMW is very slick, does not absorb water, and protects the boat bottom from rocks and impact. But this type of project is one of those cases where small business are trying to make a go of doing custom installs for people, making legitimate information on how to actually do it yourself hard to find online. It’s even hard to find good pictures of well-done applications. However, we recently found a good YouTube video that is essentially a slide show of the jet boat from its skeletal frame to being on the water. Good shots of the UHMW in application are at 8:43 into the video.

According to the video description 3/8″ thick UHMW was used, the strips appear to be about 8″ wide and would be the full 10′ length of a standard sheet. UHMW is readily thermoformable, just add perhaps 100 degrees heat to soften it. You’re going to want to attach it right after thermoforming as it will bounce back if you leave it unattached. Attachment is a concerning part of this application as many commentators on the various DIY websites will promote a type of weldable UHMW or adhesive-backed UHMW. Our experience is that mechanical affixation (countersunk holes with bolts) is the only reliable way to affix UHMW. We recommend you do your own research into the application.

You can see the video below:

Plastic fabrication questions come up often with “Do it yourselfers”. The public is less familiar with working with industrial plastic compared to wood or metal and wonder what changes need to be made. The answer? Not much.

Drilling & Bits:

For plastics solid carbide, carbide tipped and high-speed steel are most commonly used. Of the the three, carbide tippedĀ (note the difference from solid carbide!) would be the closest thing to an “all-around” bit as it offers an excellent finish with the strength of the steel core. Jarring motions and general inconsistencies working by hand means that solid carbide bits should be avoided.

Bits come in both “O-flutes” and “V-flutes”. The V-flute is better for harder plastics such as Micarta, industrial laminates, acrylic (cast). The O-flute would be better for your polyolefins (UHMW and HDPE in particular), extruded acrylic and polycarbonate. In general, the more cutting edges you have, the better as this can make your inconsistent and amateur (no offense intended) feed rates more forgiving. Higher speed drills or routers will create a better finish and a smoother action.

Sawing & Hardware:

Similar to drilling or routing, carbide tipped blades and high RPMs are best for sawing plastics. Otherwise, they cut similar to wood. Like wood, you may need to do some light sanding on the edges after cutting to deburr the plastic. Customers seem to be especially intrigued by the smooth, glass-like surface finishes in many finished acrylic products they see for sale. However, you need to know that acrylic does not finish like this with regular fabrication at home. You will need to obtain a torch and teach yourself how to flame-polish the acrylic, or use a chemically-based flame-polishing alternative. Both options have short tutorials readily available on YouTube by the “DIY” crowd (note: of course Redwood Plastics does not recommend or endorse any particular video).

We also get asked a lot about particular hardware for plastics. Unless it’s M-Clips or bolts for FRP grating then there really isn’t any special hardware for most industrial plastics applications you would be working on. It’s important with plastics you’re using outdoors to oversize the holes by 1/8″ to allow for thermal expansion and contracting using washers is key to not place too much stress on the plastic, which could cause warping.

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Sometimes here we get a little focused on the different plastics and helping you with your applications that you’re already working on. But how about a few ideas on what plastic projects you could work on using industrial plastic? Just maybe this will get your creative juices flowing…

-Hockey fan? How about a synthetic ice surface using UHMW or HDPE?

-Build your own twin-wall polycarbonate greenhouse

-Drill holes in PVC piping and affix to a garden hose in order to make a great summer water attraction for the kids

-Make home saw guides made out of Micarta

-Line your mud room with FRP wall panel to protect from grime and damage

-Replace your wooden dock with a mini-mesh FRP grating surface

-Cut and affix UHMW strips to your snowmobile steering rails or dog sled

-Make a sunroof or solarium out of twin-wall polycarbonate

-Secure your sailboat rigging with Micarta grade CE washers or blocks

-Machine at home pulleys for a home robot or model using natural nylon

-Affix UHMW to the bottom of your shallow running boat to protect from impact

-Make a bolus game “goal frame” out of PVC pipe

-Line your dog house or other animal pen with HDPE puckboard to protect the walls and the pets

For help with your “DIY’er” project’s materials contact Redwood Plastics

 

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Fiberglass reinforced plastic (FRP) has proven itself as an excellent material for use in industrial applications but there are many applications that enterprising and “handy” members of the do-it-yourself community should consider. FRP is electrically non-conductive, will resist weathering, and will not rot or rust.

1.) Docks/Walkways/Ramps – FRP molded sheet

FRP makes an outstanding material for weather resistant, and rust/rot proof, ramping and docks. With the proper design, the sheet can safely sit in a trough without requiring mechanical bolting or affixation. FRP sheet comes standard with a “meniscus” anti-slip surface but panels with a grit surface are widely stocked. The panels will be more expensive than comparable wood or metal (about $300-$400 U.S. dollars per 4′ x 10′ sheet, before freight) but for the do-it-yourselfer looking to make a long-lasting, premium design, FRP is an outstanding selection. There are even “mini-mesh” options available to help prevent small items such as keys from falling through. For me information on FRP molded sheet, click here.

2.) Wall protection – FRP wall panel

FRP wall panels are everywhere but do a thankless job and you may rarely notice them. When you’re in a convenience store or food processing area, have you ever noticed an embossed, pebble-like white or grey wall covering? This is FRP wall panel. It is chosen because it is very low maintenance – it lasts for a long time and is easy to clean. It’s also readily available in white 4′ x 10′ or 4′ x 8′ sheets, all being .090″ in thickness which is the industry standard. It is commonly affixed via a special adhesive that can be purchased alongside the sheet and it would be ideal for workshops, mud rooms, bathrooms, or any area where walls need to be protected from dirt, grime, moisture, etc. For more information on FRP wall panels contact us here.

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Redwood Plastics is the plastics distributor who runs this website and one of our most common inquiries is “Hi, I’m looking for the plastic for a greenhouse…” what ends up happening is an educational process, often via email, whereas the options are narrowed down to really your only option: twin-wall polycarbonate. The most common misconception people have is that regular acrylic or polycarbonate (the smooth stuff) is a good option: it isn’t. For one, you’ll be paying a lot more, but more importantly, the R-Value (heat insulation value) and weathering resistance will be much poorer. Acrylic has decent UV-resistance but regular unmodified polycarbonate has poor weathering including from the sun. Both options will be much more pricey than the twin-wall, which you should have been using in the first place.

Twin-wall polycarbonate has excellent R-values and resistance to UV-light and weathering. The 4′ x 10′ x 6mm profile is what we be considered “standard”. Many customers do specify 8mm or even 10mm thick polycarbonate and we often wonder why. Yes, the R-value would increase; however, you lose light transmission value. So are you really ahead? Certainly you are NOT ahead when it comes to price as 8-10mm thick polycarbonate is much more expensive. We’ve had members of the “DIY” community have excellent results with 6mm thick twin-wall in Saskatchewan where winters can reach -30 degrees Celsius. For more information on the tradeoffs between different polycarbonate thickness options, click here.

The benefits of twin-wall polycarbonate are excellent and they include:

-Ease of fabrication via common woodworking tools. Diamond/carbide-tipped blades not required.

-Relatively low price

-Full UV-stabilization/resistance to weathering

-High light transmission

-A product that is meant to be for greenhouse applications!

For a personal response to your questions on twin-wall polycarbonate, contact Redwood Plastics today.

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We wanted to bring up something amateur plastic project enthusiasts and “Do-It-Yourselfers” often don’t consider until something goes wrong: the weathering of plastic. This was inspired by the a recent visit from a “diy’er” Jason, a hunter. Jason wanted to show us a table he built for processing his game. It was a homemade outdoor table with a white plastic surface likely natural or virgin-white HDPE or UHMW polyethylene. The surface was discolored and had numerous small cracks where Jason (rightfully) was concerned about bacteria growing in the cracks but even more so, he was curious on what caused the plastic to degrade.

The answer for Jason and the culprit with many plastics is UV (ultra violet light or sun) exposure. The chemistry would take to long to explain but suffice to say the sun has damaging effects on plastic. Many plastics become more brittle and crack while others discolor, usually by becoming yellow. If you’ve ever been to an aircraft museum and seen the yellow tinted plastic (polycarbonate) canopies on aircraft? That’s from weathering and UV-exposure. If you look, very closely, at those canopies you’ll see subtle cracks that create a type of haze obscuring vision, as in the picture below.

In most plastic applications for home machinists and project enthusiasts the UV exposure is more of an annoyance than anything. We recently had a sailboat owner frustrated with the discoloration of his polycarbonate hatches he made: the same issue with those aircraft canopies. The most important thing for your project is to figure out of there would be a safety issue caused by a part weathering. In the case of Jason the hunter the cracks on his table might harbor bacteria but since the meats would eventually be cooked (and raw meat has lots of bacteria anyways) this probably isn’t a critical issue. However, in another application – such as the increasingly common homemade roller coasters – the failure of a part, such as a wheel, could be very dangerous.

If you want UV protection there is some good news. Most plastics can be procured in UV-stabilized versions. The problem is these versions are more expensive and sometimes prohibitively more expensive if the material needs to be shipped in on a special order. In the competitive world of plastic distribution there simply isn’t margin or warehouse space to stock the UV-stabilized version of every plastic. The other thing you need to realize is that UV-stabilization in plastics isn’t permanent, it just buys you time – usually no visible degradation over 10 years – but the plastic will eventually lose its UV-stabilizing properties and degrade.

The point of this article is to get you thinking and remember to consider on your next project if weathering is a concern. And for those of you with weathered plastic in your applications? Well now you know why!

For more information, contact Redwood Plastics.

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