Saturday, November 10, 2007 

How To Use Epoxies

Epoxies have a wide acceptance in the marine industry, but they haven't caught on in the wood shop as well as they should. Having been associated with the marine industry myself and with the use of epoxies for many years, I have developed a good working relationship with epoxies, and I use them quite often in place of other adhesives, especially when high strength and moisture resistance are factors.

To properly use epoxy, one must first understand the basics. Epoxy is a two part adhesive consisting of a resin and a hardener, and is primarily divided into two classes: quick-set and slow-set. They are further divided within these categories by the mixing ratios, which are designed by the manufacturer. They can be anything from 1:1 to as much as 16:1, depending on curing time, viscosity, ultimate strength and intended use.

Quick-sets are usually 1:1 by volume, so that equal amounts are squeezed from hypodermic-like syringes and mixed to a uniform color and consistency. They usually achieve their strength in 10 minutes or less, and a full cure within 24 hours, but they rarely reach the high strength that the slow sets do, and quite often retain some flexibility and resilience.

Slow-sets allow more open or working time, and can take up to 24 hours to cure. The advantages are superior strength, water resistance and gap filling capability. They don't take as much clamping pressure as other adhesives, and I have had success with only contact pressure. As a matter of fact, too much clamping pressure can force the epoxy out of the joint resulting in a lean or starved joint.

The gap filling capability is no excuse for poor workmanship, but if a mistake is made, epoxy can be very forgiving. The viscosity can be altered very easily by the addition of fillers such as sawdust, wood flour, talc, or colloidal silica. I use a product called "cabocil", which I get from my epoxy manufacturer, and in fact many epoxies are pre-filled with cabocil to moderate the consistency. In an emergency repair, I have even used copper wool as reinforcement, along with the cabocil, allowing a boat owner to get to his home port before making the permanent repair.

Epoxy cures through an exothermic polymerization, or heat producing chemical reaction in which there is very little moisture loss, resulting in less than 0.05% shrinkage, the main reason that epoxy is such a great gap filler.

Probably the greatest advantage in using epoxy is the ability to join dissimilar materials. The adhesion factor is as great on metal as it is on wood, but some non-porous materials need to be roughed up to enhance the bond.

Each manufacturer has his own specifications for mixing and using epoxy, and the instructions need to be followed closely. Too much or too little hardener can result in a gooey mess that never will cure.

Storage instructions must be followed also. Some hardeners will harden from exposure to air, and water in either resin or hardener is a definite taboo. When using epoxy that is approaching the limits of it's shelf life, the resin and the hardener should be stirred thoroughly prior to mixing together. If crystals have formed in the hardener, you can sometimes restore it by immersing the container in warm water to heat the hardener enough to dissolve the crystals.

Care must be taken to avoid excessive heat and contamination of the product with water. Stir the hardener to restore the consistency.

At as much as $50.00 per gallon, epoxies can be expensive, and because of limited shelf life, don't buy larger quantities than can be used in the recommended time frame.

Most epoxies are formulated for use in moderate weather conditions, between 50 and 90 degrees Fahrenheit. Cooler temperatures slow the curing time and warmer temperatures will accelerate it. This can be used to advantage by refrigerating the mixture to prolong pot life, or by warming the mixture to speed up the cure.

Depending on the use, application can be by roller, spray gun, trowel, or putty knife. Some are thin enough to be injected into joints with a hypodermic syringe. Clean up can be done with soap and warm water if done soon enough, or with acetone, lacquer thinner, or denatured alcohol. If using a spray gun, spray plenty of solvent through the gun to assure the complete flushing of the equipment. For safety and environmental reasons, spray the solvent into a container for proper disposal.

I am a retired professional woodworker with over 50 years experience in virtually all phases of the construction industry. I would like to pass on a few of the tips and tricks that I have learned through the years. I have written a few e-books on diverse subjects related to woodworking and construction, and am adding more all the time. Visit my store on eBay to see my books: I am now offering a limited selection of epoxies in my eBay store at: http://tinyurl.com/3chxox

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Five Easy Ways to Avoid the Flu This Winter

Many people wonder how they can stay well this winter, considering the onset of the flu season and the fear of a possible influenza epidemic. Fortunately, acupuncture and Oriental medicine provide proven steps toward preventing illness and maintaining good health in cold weather.

We hear about so many people catching the flu - but in reality it is only a portion of those exposed to a virus that get sick. Why? According to Oriental medicine's teachings, our bodies get sick when we are in a weakened state. It is only when our immune systems are weakened and our bodies are out of balance that we are vulnerable to sickness.

Acupuncture originated in China between 3,000 and 5,000 years ago. It corrects imbalances in the body's energy systems that cause illness. Practitioners of Oriental medicine identify Qi (pronounced "chee") as the life giving energy that needs to flow freely through the body for good health. Integrated with a wise lifestyle, Oriental medicine can help prevent illness.

Here are Five Tips for Avoiding Illness This Flu season:

1. exercise a little bit everyday. exercise moves the lymphatic system, thereby helping to detoxify the poisons in your body.

2. Keep warm. Make sure your neck and chest are protected from wind, drafts and cold. Use a scarf around your neck when going outside and wear turtle neck shirts or sweaters. The neck is an area where wind can invade the body and cause sickness. The Oriental medical perspective is that wind invasions make people more vulnerable to developing colds and flu. Always keep your feet warm and dry.

3. Get adequate sleep and relaxation. Your body is vulnerable to stress without enough rest. Think about doing some deep breathing exercises to help relax and unwind at the end of the day. Use stress-reduction methods like Qi Gong meditation or yoga.

4. Eat smart. Avoid refined sugars (processed food and baked goods, alcohol, etc.). A diet of refined or simple carbohydrates (white sugar, white bread) raises the body's Ph and allows bacteria, mold, yeast and fungi to thrive. Simple carbohydrates suck up the nutrition your body needs to detoxify, nourish and build new cells and antibodies. This makes you MORE susceptible to illness. Vitalize your nutrition by eating more fresh, organic foods and less processed food. This food has more "Qi" in it.

5. Get Acupuncture. When you get regular acupuncture treatments (as little as once per month) it actually boosts your immune system. Acupuncture strengthen the "Wei Qi" or the protective energy that safeguards us against colds and flu.

Use these Five Tips for Avoiding Illness to keep your body strong and healthy this winter. You can resist illness, the flu or the common cold.

For more than 19 years Steven Sonmore helped people transform their health problems into solutions for attaining better health. Steven is a licensed acupuncturist, Oriental bodywork therapist and herbalist. He offers complete health care with acupuncture, Chinese herbs, nutritional counseling, Oriental massage, and facial rejuvenation. He is licensed by the Minnesota Board of Medical practice and certified by the National certification Commission for Acupuncture and Oriental medicine. For more information visit http://www.orientalmedcare.com or write to info@orientalmedcare.com or call 612-866-4000. Copyright 2005 by Steven Sonmore. All rights reserved.

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