Perhaps no industrial plastic is more requested by the “do-it-yourselfer” community than acrylic. Prized for its beauty and well-known because it is used in many applications where the public would encounter the material (displays, aquariums, giftware). In short, acrylic has gained an impressive reputation. But when you work with the material, especially if you’re inexperienced, you really need to do your due diligence in learning the strengths and weaknesses of acrylic and learn how to fabricate it properly.
One of the first tips – especially if you’re just starting out – is to temper your expectations. People imagine they can create polished, flawless projects at home similar to what they have seen in existing products or on the internet. But acrylic is “fussy” to fabricate, it can crack easily if fabrication is done near the edges of the material, it can scratch and the nice, polished finish you see is done by a technique called “flame-polishing” which is a skill that needs to be developed and requires special equipment.
We will provide a couple key tips on this blog but also want to direct you to another blog that seems to be an excellent resource for general acrylic fabrication, which can be found here.
Some tips we can offer:
-ALWAYS leave the masking cover on the acrylic (this provides protection from cracking).
-Avoid fabrication such as drilling near the edges of the acrylic (best to leave a couple inches) as the material can be prone to cracking.
-Acrylic has good UV-resistance, use it outdoors in confidence.
-Cure time for glued acrylic is around 48 hours – be sure you have a way of stabilizing your project while the glue bonds.
Lastly, for some quick tips on gluing acrylic check out this Youtube video:
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.
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 tipped (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.
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
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.