UHMW polyethylene is probably the most popular engineering plastic for use in DIY projects. But how do you work with it? People often get overly concerned with fabrication, especially in regards to the “tolerances” needed for most home projects, but regardless here are some tips to get the most out of your UHMW application.

Sawing:

UHMW can be cut with either a circular or band saw. A band saw is best as it will vent heat away from the plastic and allow for faster cutting speeds. The band saw blades may be 10-30mm wide and about 1-2mm thick with the circular pitch between 3 and 10mm. To prevent the saw blades from becoming jammed, the teeth must be set at approximately 0.5mm. When using circular saws, saw blades with a minimum setting 0.5mm are also preferred. Normal cutting speed for band saws is 1,000-2,000m/min and for circular saws, 3,000-4,000 m/min.

Drilling:

Lower RPM drilling is recommended unless compressed air, water, or cooling oils are used – UHMW melts easily. Twist drills are most commonly used but pointed drills and circular cutters can be used for higher diameter holes.

Welding

Because of its high melt viscosity, friction and butt welding are the only practical methods for joining Redco UHMW by welding.

Machining

Machining is the principal method used to fabricate finished parts from UHMW. UHMW can be sawed, turned, planed, milled drilled, stamped and welded easily on woodworking or metalworking machines. The following general directions should be observed in these operations: To obtain surfaces of high quality, tools should always be sharp. For the most purposes, normal tool steel is satisfactory through many fabricators use special steels.

The optimum cutting speed is between 250 and 1,000 m/min. At lower cutting speeds cooling is not required, but at higher cutting speed range, water cooling or the use of soluble cutting oil is essential. In all cases, care must be taken to avoid heat build-up in the machining operation, so that the work piece does not smear the cutting edges. In milling and turning, the feed should not be too fast and the depth of the cut should be greater than 0.3mm.

Bonding

Questions about solvent bonding are common but unfortunately this is not recommended with UHMW. It resists most solvents and, at best, will create a below-average to poor bond. Mechanical fixation is recommended wherever possible.

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This is a really neat project with materials available from any hardware store. We found a video of a “do-it-yourselfer” (Alan) in Texas on YouTube who made a simple, yet rugged, sprinkler out of PVC pipe. Really not much is needed here in the way of materials and you likely could get it all in one stop to the hardware store: PVC pipe and caps, a female socket for the hose, the sprinkler, and PVC glue. The nice thing about Alan’s design is that it works better than many traditional sprinklers. You know, the ones that oscillate back and forth with separate streams of water? In this case, the sprinkler seems to even cover 360 degrees of space providing excellent coverage. If it’s an inexpensive build that works better than store bought alternatives, you know you’ve got a good idea on your hands!

 

Multi-wall (also known as “twin wall”) polycarbonate is a very popular plastic product for use by the DIY community. This is because the product is inexpensive, readily available, and easy to work with. In fact, often the most “complicated” part of the job is convincing users how simple working with the product is! Whether its concerns about special hardware, installation, fabrication or estimating what product you need – these three tips will assist you in optimizing your multi-wall polycarbonate application.

1.) Don’t overestimate the product’s thickness

Most of the customers for multi-wall polycarbonate are people using it for “residential” applications such as a home greenhouse or awning. But for whatever reason people often ask for thick multi wall polycarbonate such as 10mm+ thickness. Thick multi-wall polycarbonate is designed for large, commercial greenhouse, and for home use is overkill. In fact, in almost all cases material thicker than 6mm is not required and in fact has two disadvantages.

The first is cost, as thicker polycarbonate will cost much more than the more readily accessible 6mm variety and secondly, thicker polycarbonate lets in less light. This means that your plants in your greenhouse get less light and could grow slower and your living space below your awning could be a bit darker. Combined with increased cost and less availability, why would you want that?

2.) No special hardware, and oversize holes by 1/8″

Ok, we cheated with two tips at once. But truth is we get asked all the time to supply special hardware for multi-wall polycarbonate. In the case of fasteners, there is none. Just use whatever screws or bolts you have lying around…3/16″, 1/2″…Whatever you have. Whatever hole you do drill, oversize it by 1/8″ to account for thermal expansion and to help avoid cracking of the material.

3.) Masked side up

When you get your polycarbonate sheet you will notice one side has a masking on it of plastic film. It is that side that has the UV protective coating. And it is that side you must have “face up” or “to the outside” as it will be hit with the light.

polycarbonate-roof

One of the things we are most concerned with is connecting people with the right material for their application. Often, people especially in the DIY community generally know what they’re looking for but there is some confusion when you get into specifics. “Black” UHMW is one of the major areas of confusion for people not very familiar with industrial plastics. UHMW polyethylene is probably the best known industrial plastic and has many excellent DIY applications. However, the plastic also comes in 10+ grades with three of those grades being ‘black’ in color!

The three types of black UHMW vary widely in price and application. In many cases, when we try to help someone with selecting a ‘black’ UHMW the response is “quote them all” – that doesn’t help us, given the extra work to quote, and it doesn’t do anything to help you either!

A quick introduction on the three types of “black” UHMW:

-Black-Reprocessed: Economy-grade UHMW with regrind (colored flecks) in the plastic. It is inferior to natural grade UHMW in every way except it does have better wear properties due to cross-linking in the manufacturing process and it is about 30% cheaper. Widely stocked at many plastic distributors.

-Black-Virgin: Natural UHMW (no regrind) with carbon black. The product is equivalent to natural (white) UHMW but has better UV resistance. It is often used in rugged outdoor applications such as on the underbelly of jet boats.

-Anti-Static: The rarest UHMW for people to refer to as “black” this UHMW has additives so that small materials do not stick, such as grains. It is almost never used in DIY applications as it is very specialized.

Understanding which “black” UHMW you are searching for is critical to ensure your application is successful.

UHMW_Black

 

Hockey Puckboard

Posted: July 12, 2016 in HDPE
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Have you ever tried to get a quote on “synthetic ice”? Most of the time that refers to white UHMW polyethylene and regrettably most folks don’t understand how expensive a sheet of that material is…Several hundred dollars for the required thickness in a 4′ x 10′ standard sheet size. This sometimes makes the hockey fan give up their idea prematurely because unless you want

The good news is for many “DIY” at home hockey applications a much less expensive material will do the trick. HDPE “puckboard” is literally named after the hockey puck – it is a type of plastic sheet used as hockey “boards”. That’s a purpose it can serve in your basement or home rink as well: puck board will take the power of hockey shots and not break. Most commonly it’s used as a platform to shoot pucks off of: protecting the ground and providing a smooth surface to shoot off of.

The plastic can be had for pretty cheap from a distributor that stocks it. You can expect to pay between $80-$120 for a 4′ x 8′ sheet, which is quite inexpensive as far as traditional “industrial” plastics go. The plastic is easily worked with home tools (drills, power saws). You do need to watch out for the fact that it is not UV-stable meaning if you leave it outside you will eventually get UV damage…It will crack and become brittle, no longer holding up to shots.

That said, if you’re a hockey fan and want a cost-effective plastic to use for anything short of skating on, puck board will serve you well.

Puckboard_hockey

Fiberglass reinforced plastic (FRP) Mini-Mesh is a completely underused product for the DIY community. The product is a grey fiberglass mesh with small (3/4″ x 3/4″) openings and comes in standard sheet sizes of 4′ x 12′ and 4′ x 10′. The Mini-Mesh replaces metal and wood in flooring applications and offers significant advantages over both materials. FRP Mini-Mesh will not rust, will not corrode, will not suffer termite attack, will not absorb water, and can withstand UV exposure from the sun. It is virtually maintenance free requiring only cleaning as you deem necessary. The small size of the openings in the grating is designed to prevent objects such as keys from falling through below.

This makes the product excel as a deck or a dock. FRP Mini-Mesh is lightweight and easy to install – the easiest way is to build a frame out of metal angle and anchor the FRP sheet in. Specialized hardware called “M-clips” are available for a few dollars apiece to anchor the Mini-Mesh into the frame but if the frame is measured properly this anchorage is often not needed. The Mini-Mesh will supply a long-lasting, weather resistant, near-zero maintenance deck or dock.

The design parameter you most need to be concerned with is span. FRP is very strong; however, it is also more flexible than metal or wood. This means that as the span gets wider the FRP will store energy when you walk on it (flex down) and then push back up. On large spans, this effect can destabilize the individual leading potentially to a fall. Spans between 1.5′-3′ are high recommended and load tables can be supplied.

The only potential drawback to the product is the cost involved compared to metal or wood. The FRP grating will be significantly more expensive than metal or wood alternatives (several hundred dollars per sheet before freight costs) so not everyone will have the budget. However, you “get what you pay for” and the advantages of FRP over competing materials is well worth the price premium. For questions or pricing on FRP Mini-Mesh contact us today.

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Jet Boat UHMW

Posted: June 13, 2016 in UHMW
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Late spring has hit the northern hemisphere and in many places it’s warming up consistently now. For many parts of Canada and the U.S. “jet boating” is a seasonal pastime. Jet boats are wide, somewhat flat-bottomed boats designed to shoot across shallow creeks, even sometimes jetting from creek across land, to a creek on the other side. Needless to say, the hulls of these boats take an absolute beating!

That’s where industrial plastic comes in. UHMW polyethylene is used on the bottom of these boats to protect against impact and abrasion. UHMW tests as unbreakable according to ASTM D256 and is also very slick, helping the boat pass any obstacle. For the most part, the boat bottoms are flat perhaps with a slight curvature. The material used is typically 3/8″ or 1/2″ thick UHMW either black-reprocessed or black virgin. The virgin material is more expensive but has about 20% better properties in most respects. If you watch jet boating videos on the internet you almost always will see a black plastic on the bottom of the boat – that plastic is UHMW.

Our recommendation is to mechanically affix the UHMW using bolts or weld washers. UHMW is available from certain vendors with “adhesive” but we have only heard of poor results and this is not recommended!

If you’re looking for a quote on UHMW for your jet boat you can contact Redwood Plastics.

Jet_Boat