Space Shuttle Challenger and Rubber: A Cautionary Case Study

The space shuttle “Challenger” explosion in 1986 was a seminal moment for many Americans. The launch was shown on live TV and there was a high amount of interest in teacher Christa McAullife being on the flight. The shuttle exploded 73 seconds into the flight resulting in the deaths of the entire crew. An immediate investigation was launched and it was determined that a failed rubber o-ring system used as seals on the solid rocket boosters led to the explosion. The launch was on an unusually cold day – the o-ring seals were qualified for use at no less than 40 degrees Fahrenheit but the temperature got as low as 18 degrees Fahrenheit the night before.

Prior to launch several engineers attempted to warn against launching due to this reason. The engineers believed that the cold temperatures would weaken the rubber and also lead to a poor seal, which would allow hot exhaust gases to potentially escape the boosters and cause catastrophic damage. It had already been determined that the o-rings were being damaged even on successful flights. The engineers were forced by NASA management to try to prove that the application would fail at low temperature, something the engineers could not do because of a lack of testing data.

Your application with rubber will likely not be as critical as the space shuttle o-ring seals; however, even with our applications there is much to learn.

Firstly, is you need to pick a rubber that will work within the parameters of your application. You need to know what chemical exposure and temperature range the part will need to operate in.

Secondly, once you get the parts you need to use them within the parameters that you have specified because if you introduce, for example, new chemicals or operate the part outside of the prescribed temperature range, it may fail!

The third and final thing we can learn is to listen to the product experts who helped recommend a rubber solution to you. If they strongly believe a certain material is required and can give you concrete reasons, you should consider this thoroughly before going in another direction. This is particularly a concern where a desired price may be a determining factor for a purchasing decision, rather than if the rubber is actually suitable or not.

Redwood Plastics and Rubber has rubber experts standing by to help recommend the best product for your application so contact us today.

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Why Choose Silicone Rubber?

Silicone is a remarkable variety of rubber that offers some outstanding properties that can make it the clear choice among competing solutions. Firstly, silicone can handle very high temperatures in operation, up to 230°C (446°F). This allows it to maintain its properties at elevated temperatures that many other rubbers will not be able to handle! In addition, it has excellent resistance to UV and weathering, making it outstanding in outdoor applications. This includes heat, cold, freezing, direct sunlight, etc.

Silicone also has a low compression set – this means it can be compressed for a long period of time and will bounce back to close to its original profile when the weight has been removed. Think of this in a sealing application such as a door which is open and closed many times. The silicone will maintain the seal when compressed and will then return to its original form once the door is reopened. Also, the product is food safe and Redwood Plastics and Rubber can supply it in a new FDA blue variety.

There is a silicone rubber shortage currently in North America but not here! Redwood Plastics and Rubber carries significant levels of silicone stock in our central warehouse including FDA blue. For a discussion on how silicone rubber can benefit your application or for a quotation please contact us today.

Rubber: It’s Not Just Tires!

When you think of “rubber” what is the first thing that comes to mind? It’s probably car tires, perhaps tires on your bike, but the point is “just tires” for many people. However, rubber is so much more than just tires. Rubber is used across a wide variety of industries performing in countless applications. Some are interesting, such as in prosthetics or medical devices. Others such as belt skirting on an ore conveyor are perhaps less interesting to the casual eye. Used in everything from mining, to sawmills, to even space – rubber should not be discounted as a simple material for tires! Gaskets, rollers, flanges, molded parts, wear parts, anti-vibration applications, electrical insulators – rubber has a place in all of those applications.

The short video below will display more applications that this versatile material can be used in. Maybe it will jump start your mind for a rubber application you might have?

Industry Spotlight: Aggregate

The aggregate industry is defined by the processing and movement of extremely abrasive wet or dry materials, usually by a network of conveyors. This process may also include equipment to pulverize, shape, clean, or otherwise sort the aggregates. Due to the abrasive nature of these materials, wear is a major concern on expensive equipment. Redco products have supplied viable, downtime-reducing, solutions for this industry over many decades. The primary workhorse is Redco polyurethane. This elastomer has extremely high wearing properties and can thrive in abrasive environments involving virtually any wet or dry aggregates.

The applications are too many to name but conveyor and hopper lining are two of the largest. When used as a liner, urethane protects the metal equipment and handles the wear of being in direct contact with the aggregate. However, polyurethane can essentially be used anywhere this wear occurs, including the area the aggregate first contacts the conveyor to any discharge chutes. Contact us with details of your application in order to get a recommendation of the optimal grade of urethane. Some polyurethane products actually exist specifically for aggregate including the innovative Redco Switchblade belt scraper with its replaceable and Redco Green Screens.

A few more notes. Rubber has significant applications in this industry as well, primarily as belt skirting and in areas where constant vibration is a concern. For slurry applications specifically, the Redco VYPUR series of pipe sections and elbows provide exceptional service life above and beyond metal in abrasive or corrosive applications. It’s best if customers reach out directly to us for a consultation, so if you’re involved in the aggregate industry and are looking for some solutions to maintenance costs and downtime, please contact us today.

You can see pictures and read more about our aggregate solutions here: https://www.redwoodplastics.com/industry-solutions/aggregate/

Not Sure What Rubber You Need? Start Here

Ordering rubber products is easy enough when you know exactly what you need and a defined spec is available. However, what if that information has been lost? The answer is to start at “square one” and work your way up to an optimal solution. To that end you need to know five pieces of information:

  • Application – What are you doing with it?
  • Contact with – What aggregates or other materials will contact the rubber?
  • Exposed to – which chemicals?
  • Operating Temp – Lowest and highest?
  • Durometer – What is the hardness (example, 60A)?

The first four pieces of information on the list must be supplied by the customer and should be easy to put together. “Durometer” is a little trickier if not known as that requires a specialized piece of equipment. In that case, a sample of material can be mailed to us and we can test it here. Having this information will help us, help you maximize success in your application.

For assistance with your rubber needs please contact us today.

Industrial Plastic: Strengths And Limitations

One of the key questions we ask customers is “what is the application?” This question isn’t asked in order to steal your idea but to ensure that the plastic you’re looking for is optimal, or even workable in that application! Industrial plastics are excellent mechanical materials overall; however, like anything they do have both strengths and limitations. This article will review the core line of industrial plastics we carry, give the strengths, the limitations, and common applications/places where the plastic is wrongfully specified.

UHMW Polyethylene

Strengths: Well balanced properties, economical, and readily available.

Weaknesses: Poor dimensional stability

Specification errors: high load bushings, unrealistic tolerances, not compensating for thermal expansion.

 

Nylon

Strengths: High load bearing strength, diverse formulations, suits a wide variety of applications.

Weaknesses: Absorbs water, poor impact and cold-temperature properties.

Specification errors: Impact parts, marine applications (without accounting for swell), using nylon bushings in high RPM applications.

 

Acetal

Strengths: High load bearing strength, replaces nylon in “wet” applications, machines to excellent tolerances.

Weaknesses: Impact, temperature (especially steam) resistance.

Specification errors: Using black (copolymer) acetal in food processing applications. It is not food-safe, unlike the blue and white.

 

Tuffkast

Strengths: Excellent impact, cold weather, bearing, and moisture-resistance properties.

Weaknesses: High cost, elevated temperatures.

Specification errors: Typically in applications that generate high internal heat, such as a hammer cushion for pile drivers. Tuffkast is also softer than nylon, which can lead to increased wear in certain applications.

 

Polycarbonate

Strengths: Extremely high impact strength.

Weaknesses: Very prone to scratching.

Specification errors: As glass/sight part without upgrading to a anti-scratch version of the plastic.

 

Acrylic

Strengths: Scratch resistant, economical, stronger than glass, fairly resistant to weathering.

Weaknesses: Difficult to fabricate, prone to cracking.

Specification errors: Using in “Do-it-yourself” projects without proper knowledge of fabrication procedures.

 

Polyurethane

Strengths: Impact resistance, rebound, good bearing strength (bearing grades only).

Weaknesses: Water saturation degrades the plastic (especially softer grades), vibration degrades the plastic’s composition.

Specification errors: Vibration or moisture applications.

 

Rubber

Strengths: Lots of choice between properties, cost, wide application variety.

Weaknesses: Polyurethane is superior in many applications, grades must be selected carefully.

Specification errors: Choosing an ineffective grade of rubber for an application to save on cost, assuming the lower grade will still function.

For more information about which plastic is best for your application, please contact us.

Plastic Plow Blades & Cutting Edges – Saving The Paving!

One of our employees recently took a couple photos after parking at an area we won’t disclose in Metro Vancouver a day after a recent snowfall. Upon pulling into his parking spot he noticed that every single stall had a large pothole where the snow had been pushed. Having been a weekly visitor to this lot he knew the holes were not there a few days before and therefore must have been caused by the snow removal contractor. The damage is extensive and will be a huge headache to fix! How much money will it cost to repair? What will happen to the reputation of this snow removal vendor?

And it was a completely avoidable disaster that never needed to happen.

Industrial plastic plow blades (or “cutting edges”) have been used for years to prevent this sort of issue. The cutting edges, made of polyurethane, rubber, or UHMW, are simple rectangular strips that are bolted to the bottom of a metal plow or bucket. Therefore it is this softer, non-damaging, plastic surface that actually touches the ground as the equipment scrapes and pushes the snow instead of the metal blade. There are multiple ways the metal-on-pavement contact can cause damage as besides creating potholes the blade can also destroy things like lights or reflectors embedded in the asphalt. Such as is common at airports for example.

The blades are an investment: even the least expensive blade will be at least a few hundred dollars. But how much is that few hundred dollar investment compared to losing contracts, a hit to your reputation as a contractor, and even potential lawsuits? The simple fact is you are “playing with fire” if you don’t have a high-quality plastic cutting blade – it’s an investment that must be made! Several plastics with different prices, properties, and suitability to applications are available so please contact us with the details of your application.

And save the paving!

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