The Much Maligned Clam Shell Blister Pack


No, not that kind of clam shell. No one has a problem with that. You know what I’m talking about, the clear, impossible to open, nearly sliced your hand off while trying to open it with a butcher knife, packaging that everything from toys to batteries seems to arrive in. This kind:


I’m not going to try to dissuade you from despising this type of packaging. I just want to explain what they are made of and why they are used.

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Tensile Strength: Yield or Break


Most of us in the plastic materials industry have some familiarity with the various ASTM and ISO test methods that are reported on data sheets and certificates of analysis. However, if you do a deep dive into any of the test methods, and by deep dive I mean read from stem to stern, you will find all kinds of things that you might not have thought of. Having set up and run an accredited testing laboratory in the past, I performed deep dives into many of the ASTM and ISO procedures.

Today, I want to explore one small part of the ASTM D 638 procedure for tensile properties. Before you say that you would rather drink battery acid, let me assure you that I will not dive too deep and I will leave you with some practical information and you will be able to point out a mistake on a lot of data sheets and certificates of analysis in the future.

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All About Moisture Analyzers

Image: Sartorius

A moisture analyzer is a great tool for any plastic processor to have. It will tell you for sure that you are drying the material adequately. It is also a great tool for material suppliers to have so that they can aid customers who are trying to troubleshoot problems.

How exactly a moisture analyzer works seems like a bit of witchcraft. You put a bit of material in, you choose some type of program and hit the start button. Ten to twenty minutes later, the readout shows a percentage. The process is a little bit more complex than just heating the material and burning off the moisture weighing the sample before and after. You don’t need a moisture analyzer to do that, you can do that with a lab dryer and lab balance. How does it work?

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Get Your Pressure Right

Hydraulic Pressure vs Plastic Pressure

When we refer to injection pressure, we can be talking about one of two things. We can be talking about hydraulic pressure which refers to the pressure that the hydraulic ram is exerting on the screw or we can be talking about plastic pressure which is the pressure that the screw puts on the melted plastic.

These two are not the same thing and if you specify an injection pressure range on your processing guides, you should only specify hydraulic pressure and you should be very clear about it.

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James May: “Car makers charge a hefty premium for it, but it’s nothing more than a by-product of cheeseburgers. Maybe it’s time for us to move on.”

Image: The Times UK

A few weeks ago, I posted a story suggesting that automakers, especially higher end automakers, should start offering vegan interior options (you can read it here). It seems that James May formerly of Top Gear fame and now on The Grand Tour on Amazon agrees.

He has some real issues with an older vehicle with leather interior. You can read the article in The Times UK here.

My old BMW and it’s Painted Plastic Parts


It had been many years since I had driven a car that was older than 3 years. Being in plastic material sales and in management positions for a number of years, I had company cars that were leased. Basically from 1990 until 2010 I leased 8 different cars on 2 to 3 year leases. Turn and burn, one after another.

In 2010, I was self employed and my finances had taken a hit from starting a company in September of 2008, right before the bottom fell out of the economy. The lease from my 2007 Infinity G35 was coming to an end. I thought about buying the Infiniti instead of turning it in, it had been an excellent car. However I decided to buy a car that I had desired for a while, a BMW 335i. I started hunting for a used one online and finally came across  a three year old example that was the exact car that I wanted at a dealer in San Francisco.

I planned, at the time, to keep the car for 3 to 4 years and then I would trade it in something else. Sometimes life gets in the way of our plans. I still have the car, now almost ten years old. It has been interesting driving a rather complex German car so far out of warranty. I wanted to talk about how it has held up.

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