Archive for September, 2011

The Value of a Life

September 30, 2011

The other night we witnessed an execution – virtually – on TV. This Georgia man is now dead. And in Connecticut, the animals accused of the viscous murders in that state (one of whom has been convicted) also exposes the death penalty to the world via television. I wonder why the United States likes the death penalty – I am appalled – I am dismayed – I am almost ashamed to be a human. Here in Texas, the State executes someone every other day or so. I’ll tell you why the death penalty bothers me so much…

Have you ever “cast a stone” to mete out justice? I have – I have been witness to an execution and asked to participate.  It made me sick to my stomach. I realized then that the world was less civilized than I wish it were. Let’s turn back the clock nearly thirty years: In Shororah, Saudi Arabia, In that small city’s central square one Friday morning while buying some food for breakfast, I was lead by the arm by a Mutawah – a member of the religious police force – to participate in an execution. I was handed a stone, marched close to the front of the spectacle, and commanded to throw the stone at the criminal along with the more than one hundred other people who had gathered there. I tossed my stone at his feet, and I left.  It was striking – I could see fear in the criminal’s eyes, and anger in the eyes of each person in the crowd who had gathered to execute this man’s sentence. I guess that I don’t believe in “an eye for an eye”. I believe in justice, but I know that I believe in “throwing away the key” in lieu of “casting the stone”.

I wonder why people don’t value life more. I wonder why justice does not strive to salvage the criminal’s future value more. I read somewhere that it costs more than $40,000 to incarcerate someone for a year. For three or four times that, you could employ a psychiatrist  to “repair” a number of criminals and perhaps significantly stem the repeat offender syndrome for a group of convicts – and save a significant amount of money, I bet. But we don’t look carefully at the lifecycle cost of social issues – we look almost exclusively at a minimal cost for a minimal mission and a minimal return. And most criminals just continue to be criminals after their sentence is served with little future value in society.

Suddenly, I don’t seem to sound much like an engineer… But I am certain that almost every life has some value, and society’s challenge is to find a way to eke the value from the most evil criminals rather that simply taking their lives. I am sure that is a challenge, but a noble one, and a civilized one.

I need – I need a really good adhesive…

September 25, 2011

I have another “pet project” in my brain – a stainless steel gadget with three pieces that need to be joined together. I want this thing to be seamless to the touch – I can’t use fasteners. I have played with brazing and soldering with limited success – surface preparation is crucial to a good join, and any void or other flaw in the braze or solder eventually leads to corrosive failure from inside the join. So, I turned to adhesive technology – I need a really good adhesive…

I thought this would be a simple problem to solve.  I contacted 3M and Henkel (Loctite) – I figure I need a notch or two below the exotic, and these two companies should be able to help me. These companies have comprehensive product lines, tech support staffs are accessible, and there are plenty of publications from these companies to refer to. Now, have you ever called the IRS with a complicated question? And you called back to see if the second answer you got matched the first answer? They didn’t? Well, it seems that adhesives are a little like taxes…

Here is the problem description:

  • Substrates: 316L stainless steel to 316L stainless steel;
  • Static Forces: 100Kg of sheer force and 10Kg cleavage force (like bell peel) – pulling and twisting, in other works – no compressive force;
  • Dynamic Forces: Occasional impulses of force that double and triple the sheer and cleavage stress – no vibration;
  • Ordinary Physical Environment: 35C to 45C, 95% humidity (noncondensing – slightly acid from sea salt) – no submersion; may be exposed to water, detergent and drying heat to clean every month or so;
  • Color: Colorless, off-white, tan, light grey would be good – not black;
  • Join #1: Plate to plate (flat to .1mm) 1cm x 1.5 cm;
  • Join #2: Wire to plate – 3mm diameter wire with 1 cm over the plate.
  • Working time: At least several minutes – almost anything will work – not an issue…;
  • Cure time: over night, but up to 3 days will work – can heat cure if necessary – also not an issue;
  • Non-sag (viscous): not an issue for Join #1 – a high viscosity adhesive may be helpful for Join #2;
  • Production: several per week maximum; adhesive budget for up to $50/week.

With all that, I would have thought that someone would have said, “You obviously need product A for Join #1 and B for #2.  Those are obviously your best choices.” But, I got a different answer every time I talked to someone. How frustrating. No one who was accessible had any experience using the adhesive products they were discussing. These companies were not paying for experience that was facing the customer! Dad-gum-it. Experience for products with a broad range of critical applications is crucial, and it wasn’t there.

To 3M’s credit, I eventually got indirect access to a chemist, but I couldn’t talk to this employee directly. To Henkel’s credit, I eventually got direct access to the product line manager who knew the product line frontwards and backwards. These individuals were ultimately helpful. To the credit of both of these companies, they sent me several free samples of a variety of products (in lieu of a definitive answer) to play with and determine for myself what would work best. 3M sent me a dispensing gun, and Loctite made sure I had plenty of hard to get 10:1 static mixing nozzles. These companies did everything possible to get their products in my hands.

So, I still have a few unanswered questions:

  1. What material is 316L stainless most similar to with regard to surface bonding? Aluminum or cold-rolled steel (these two materials are commonly tested for manufacturer test data)? Is there a different answer for epoxies and for acrylic adhesives?
  2. What is the optimum bond thickness for each candidate adhesive for Join #1 (not always stated on the tech data sheet)?
  3. What is the optimum surface preparation technique for epoxies and for acrylic adhesives (there is a difference of opinion between companies)?
  4. What is the effect of monthly thermal cycling from 40C to 120C to 40C on the bond lifetime?
  5. What is the typical viscosity of a paste? A light paste?

Here are the products I have to trial – anyone recognize a winner:

3M – for Join #1 – VHB Transfer Tape, DP420, DP460; for join #2 – DP460NS (three epoxies);

Devcon – Metal Welder (an acrylic);

JB Industries – JB Weld;

Loctite H4710, H8500, H8600 (three acrylics for Join #1), E-60HP, E-214HP (two epoxies for Join #2); E-60HP may also work for Join #1.

LORD – 310 (medium viscosity, general purpose epoxy).

This will be a fun Thanksgiving project! I’ll report back… Anyone know answers to my questions???