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.
We recently found a video on Youtube, and while we can’t vouch for how well it would work in your application, it looks to be an ingeniously simple solution that would apply to many applications other “Do-it-yourselfers” would have. In the video, the publisher needs to fix a hole in his HDPE jet boat (we’re betting this is a fairly common problem).
The video creator’s solution is to take a knife and shave some HDPE from an area under some molding, where it wouldn’t be noticed, then take a regular soldering iron to melt that plastic into the hole. He then takes a blow torch and brushes the surrounding area, which softens it, and allows him to then take 40 grit sandpaper: blending the patch in with the hole. The benefit of this approach is obvious: the plastic and color will be a match and only simple tools are required. In essence, you are grating plastic akin to a skin graft operation. Also, you don’t need to purchase additional plastic to create the patch.
If this idea interests you, check out the video right here:
Plastic synthetic ice is an increasingly popular “do-it-yourselfer” project for hockey fans. The ice allows year round training regardless of weather conditions. This blog is supported by Redwood Plastics, a plastics distributor, and increasingly we’ve had “synthetic ice” inquiries that actually refer to two different applications. “True” synthetic ice is a skating surface and the application can take a couple forms. Primarily training arenas will have the player suspended by a harness while skating on a single sheet. Because synthetic ice requires about 20-30% more effort to skate on, this improves strength and conditioning. The other format is having a full rink of sheets essentially as a replacement for ice.
There are two types of plastic used for this. One is HDPE polyethylene that has additives to make it optimal for skating, this would be “true” purpose-manufactured synthetic ice. Secondly, white-virgin UHMW polyethylene sheet is used. The UHMW is slicker and stronger than the HDPE but, as you might expect, it’s more expensive to the tune of about 25% more. The issue you need to solve as a “diy’er” taking on this project is how to make your rink. The sheets are just that – flat sheets.
There’s no set hardware for the application, though synthetic ice specialists may be able to offer some help. Otherwise you’re on your own and you essentially need to find a way to put the sheets together, tightly, but without hardware or holes sticking about the surface of the sheet. Usually this means the sheets are placed in a cavity that holds the sheets together and prevents them from moving. For example, a frame made of 2×4 wood bolted into the ground along the perimeter. Do not listen to what you might hear on the internet: adhesives or glues for the sheets will not work!
The second reason people approach us as a distributor for synthetic ice is for a simple platform to shoot pucks off of (or at). In this case, the customer requests UHMW polyethylene or ‘synthetic ice’ but they don’t really need that. It’s “overkill”. Truth is, a cheap plastic sheet – HDPE puckboard – will work just fine in this application, taking a beating and still slick enough to shoot pucks off of (but not skate on). When you’re working on a synthetic ice project you really need to know what you’re looking for!
For more information contact us.
We recently came across the website of a creative fellow, Dave Hendricks, from Allentown, PA who manufactures boomerangs. Wood probably comes first to mind when you think of a boomerang but these are a little more hardcore. Polycarbonate plastic machines better than acrylic (less cracking) and it has tremendous impact resistance making it an excellent choice for a tool like this. Admittedly, this is a little bit of an advanced project where you’ll not only need a router but also knowledge or blueprints of how to make a functioning boomerang but it can be done. Some tips on the routering a boomerang can be found here.
Furthermore, you should know that polycarbonate boomerangs will require intermediate skills to throw well. They require better technique, more spin and more power than their wooden counterparts. While this project might be a little obscure it sounds like a lot of fun for the “do-it-yourselfer” looking for a challenge.
You can find out more about these boomerangs at David Hendrick’s website: http://www.bvdrangs.com
You know what they say about simple ideas – sometimes they’re the best!
We found a video of a DIY project where a CNC machine is used to etch a ball maze into a piece of acetal plastic (of which the name of the homopolymer variety is ‘Delrin’). Apparently the project was for students who designed the game from an initial paper sketch all the way through the CAD program. This project is simple enough for students yet creates a functional and fun piece of work. In short, it seems like genius. Acetal is a great plastic for machining, probably the best thermoplastic in holding tight tolerances.
Acetal has numerous other “Do-It-Yourselfer” applications. Most common is probably aftermarket paintball equipment, which we have blogged about previously here. Acetal replaces small, precise metal parts and often replaces polyamide (nylon) in applications where moisture is a concern.
The video is a little blurry but you will still get the gist of the project and the final design:
Posted: December 2, 2014 in UHMW
Tags: polyethylene, sled, toboggan, uhmw
It’s winter and it’s cold through much of North America. But if you can’t beat the deep freeze you might as well have fun with it, right?
One of the most fun – and easiest – industrial plastic projects you can work on for winter is a UHMW toboggan. Snowmobiles and dog sledders know well the benefits of UHMW polyethylene for sled tracks. UHMW is economical compared to other industrial plastics and has a very low coefficient of friction combined with no water absorption. In short, it will make your sled glide smoothly over the snow and ice. In fact, UHMW is a cryogenic plastic meaning that its properties actually improve in cold temperatures. But while sledders bolt UHMW rails to the bottom of their metal rails an entire toboggan can actually be made out of UHMW.
It’s simple too, information is widely available on the internet. Essentially you need a sheet of UHMW (natural-white seems to be used the most) about 12″ x 120″ long and 1/4″ thick. This will set you back about $90.00. Next, you need some rope and some 1-2″ wide x 12″ long wood (to be orientated as spars across the UHMW strip) and finally, some flat ended bolts. You tap the wood for the bolts, affixing theme to that the head of the bolts touches the snow (there will be less friction that way). The rope is particularly important to bend the front of the toboggan to produce that signature curl…And that’s pretty much it. You just need some snow and you’re on your way!
Information, tips and instructions are widely available on the internet but here are a few pictures of how a successful design should look:
Posted: November 13, 2014 in Acetal
Tags: Acetal, black nylon, guitar pick, ULTEM
One everyday application that uses performance industrial plastic is guitar picks. The rigors of many thousands of abrasive strokes against guitar strings means quality plastic is ideally suited to this application. ULTEM (semi-transparent amber or black color) is sometimes used but acetal (opaque white or black) is more common. Black nylon is also a good plastic for this application but is less well known. We recently found a website all about a do-it-yourself product called the “Pick Punch” this lets you take acetal and punch your own picks at home – you might never run out again! This is much more economical (and fun) than simply buying picks, wouldn’t you say?
The website gives lots of tips on how to finish your picks as well as which types of plastic or items to NOT punch with the machine. You can check it out here: http://www.pickpunch.com