The DIY Files: Home-Improvement Myths

It’s funny how urban legends seem to gain credibility as they pass from person to person. Repetition and embellishment, which often involves supposed experts or indisputable facts, can lend even the wildest fabrications a sense of stranger-than-fiction veracity.

Among the obvious tall tales – featuring men in black, alien conspiracies and ghostly hitchhikers – stories of home improvement wonders or mishaps often command a surprising following.

To find out where the facts end and the folklore begins, our team of paranormal home-improvement investigators examined a baker’s dozen of common DIY-related beliefs. After all, as the lead character in a television show was famous for saying, “the truth is out there.”

DIY File X-001: The case of the cupping deck
To eliminate any chance of cupping when building a deck, always orient the deck boards with the bark side facing up.

Fact: Though there are strong opinions in both the bark-side-up and bark-side-down camps, studies conducted by the Southern Forest Products Association (SFPA) have shown that there’s very little difference in cupping resulting from orientation. “To truly minimize cupping, the real solution is to properly fasten the deck boards to the joists,” says Richard Kleiner, director of treated markets for the SFPA. “Make sure to always use fasteners that are rated for your decking material.”

DIY File X-002: Motor oil magic
Applying used motor oil is an effective, inexpensive way to achieve a dark, rich finish on deck boards.

Fact: This is an effective, inexpensive way to ruin your deck. Motor oil will indeed stain wood, but unlike deck finishes, it has no drying agents. It won’t cure, and it will collect dirt. Instead, use a manufactured penetrating deck finish that’s appropriate for the type of wood from which your deck is constructed.

DIY File X-003: No need for primer
When repainting interior walls you don’t need to use primer, as the existing paint will serve the same function.

Fact: This tall tale has an element of truth, but it doesn’t tell the whole story. Primer serves several purposes: It provides a nearly white surface that doesn’t affect the color of the new paint, it maximizes adhesion of the new paint and gives it a uniform sheen, and it blocks any stains from showing through. Although in some cases you might be able to skip the primer, it’s not typically recommended.

According to the experts at the Rohm and Haas Paint Quality Institute, you can get by without using a primer only if the current paint surface is in good condition and the new paint has a flat finish and is white or a very light color. If there are any stains on the walls, if the paint is darker than a pastel color or if the new paint has an eggshell, satin or semigloss finish, first apply a latex stain-blocking primer recommended for interior surfaces. Even if there are no stains on the existing paint, a primer will help to ensure that the new paint has a uniform appearance. If in doubt, use primer; it will be worth the effort.

DIY File X-004: The way to abolish weeds
As long as you install some type of weed barrier in landscaping projects, they’ll remain weed-free.

Fact: Although landscape fabric does serve a specific purpose, it does not guarantee a weed-free landscape. “Weed barriers are great for preventing existing weed seeds from germinating,” says Amy Sitze, former editor of our sister publication Gardening How-To. “However, when you put organic mulch like wood chips or shredded bark over the weed barrier, those materials slowly break down and form great soil for any new weed seeds that happen to drop in. If you catch these weeds when they’re small, they should be easy to pull out. They’ll be tougher to remove if you let them go until their roots penetrate the weed barrier.”

DIY File X-005: The exploding compressor
An air compressor can explode if you don’t take proper care of it.

Fact: This is no myth. An air compressor builds up a volume of compressed gas (in this case, air) within a chamber. As the pressure within the tank increases, so does the temperature within the tank. Likewise, the pressure decreases as the air is released to operate tools, so the temperature decreases (an act that’s scientifically defined by Charles’ Law). As the temperature lowers and pressure drops within the tank, moisture in the air condenses on the inside of the pressure tank. If that moisture isn’t drained, it will corrode the inner surface of the tank and lead to weakened tank walls.

There are two ways to avoid this problem. First, regularly drain the built-up moisture from the compressor tank using its drain valve. Second, whenever possible, avoid the rapid release of large volumes of air - the faster the pressure drops within the tank, the more likely it is that condensation will form.

DIY File X-006: Restoring natural oils
It’s possible to revive the luster of wood furniture by applying a treatment that replenishes lost oils.

Fact: This myth has been around for a long time, and the labels on some familiar polishes and restoration products make such claims. But the truth is that most wood doesn’t contain any oils, so it’s impossible to replenish what was never there. Some exotic species such as teak are oily and can be renewed both in color and in sheen with an application of appropriate oil. But for most furniture made of oak, walnut, cherry, poplar or pine, there’s simply no oil to replace.

Instead, use a high-quality wax or polish to liven up an otherwise dull-looking finish – just be careful with any polish that contains silicones, as they may soften some finishes and can cause fisheyes if the piece ever needs refinishing.

DIY File X-007: Things that go “boom”
Thanks to numerous safety fittings, it’s impossible for a modern tank-style water heater to explode.

Fact: Don’t be lulled into a false sense of security -- I’ve seen photos and police reports of water heater explosions. As with air compressors, the culprit is pressure. Water heaters are equipped with a temperature pressure-relief (TPR) valve that releases both hot water and built-up pressure if either gets too high. If the valve malfunctions, the heater can explode.

Test your valve periodically by quickly tripping its test lever. If water pours out of the discharge tube, the valve is clear of deposits and capable of performing its job. If it has been a while since you’ve performed this test, or if the valve is old, be aware that it might become stuck in the open position during testing. Before you begin, know the location of your main water shutoff in case this happens.

DIY File X-008: Krazy first aid
In an emergency, you can use cyanoacrylate glue (such as Krazy Glue or Jet Glue) in place of stitches to close and seal wounds.

Fact: Cyanoacrylate adhesives cure on contact with trace amounts of moisture and form a very strong bond. The first such adhesive was methyl cyanoacrylate, the type that’s currently sold for hobby and woodworking applications. But because the methyl alcohol it contains creates heat when it cures (and can damage tissue), it was rejected for medical purposes.

In the early 1960s, researchers discovered that changing the alcohol in the adhesive from methyl to butyl kept the adhesive from producing heat, making it safe to use in medical applications. Today, all medical-grade tissue adhesives contain butyl-esters, whereas hobby and woodworking varieties still contain methyl alcohol. Used very sparingly in an emergency, hobby-grade cyanoacrylate glues can seal minor cuts and more serious lacerations, but they should never substitute for proper medical attention.

DIY File X-009: The worthless white glue
White glue is inadequate for anything but craft projects. For everything else, you must use yellow wood glue to achieve the best results.

Fact: Many woodworkers fall prey to this fallacy. Both white and yellow glues are polyvinyl acetate (PVA) adhesives. Although yellow glue has a higher initial tack (and yellow coloring to set it apart from white glue), there’s no functional difference in the relative strength of their bond.

ASTM International (originally founded as the American Society for Testing and Materials) evaluates glue with the D905 standard, a test that determines the comparative shear strength of adhesive bonds. In laboratory tests, Titebond’s all-purpose white glue and its yellow wood glue demonstrated exactly the same shear strength. The only differences during testing were in viscosity and set time. And depending on the complexity of your project, a longer set time may be an advantage.

DIY File X-010: Drying time for decks
Pressure-treated deck lumber needs to dry for two to three years before it can be stained; applying stain sooner will prevent the wood from weathering properly.

Fact: Pressure-treated lumber is often slightly damp when it arrives from the lumberyard, but if you wait a year before staining, the wood will suffer damage from the elements. Richard Kleiner from SFPA recommends a four- to eight-week drying time. “What you’re after is a surface-moisture content that’s less than 20 percent,” he says. “Twelve percent is ideal, but anything less than 20 is acceptable.”

Two exceptions to this rule of thumb exist. First, lumber that is kiln-dried after treatment (KDAT) can be stained immediately. Second, any lumber that comes treated with water repellant from the manufacturer should be left alone for two to three months before you apply stain.

DIY File X-011: The deadly battery discharge
If you store an automotive battery on a concrete floor, it will quickly discharge and become a worthless pile of lead.

Fact: Many years ago, batteries were constructed with a wooden case around a glass jar. Any moisture on the floor could make the wood swell and possibly fracture the glass, causing it to leak. Although rubber battery cases later replaced wood, they were still somewhat porous and could allow current to be conducted through the container and into the concrete upon which the battery sat. With the construction of modern automotive batteries, however, such precautions are usually unnecessary.

DIY File X-012: The cordless battery buster
It’s a good idea to completely drain a tool battery by taping down the tool’s trigger and allowing it to run out before recharging.

Fact: With devices such as cordless phones, it can be beneficial to totally drain the battery to prevent what’s referred to as “memory,” a fatal battery condition that robs runtime from the device. But for cordless tools, running down the battery by taping down the tool’s trigger may be the worst thing you could do.

“One of the biggest myths is that you should run your battery all the way down before you recharge it,” says Christine Potter, a senior product manager for DeWalt Industrial Tools. Doing so could inadvertently cause individual cells within the battery pack to reverse polarity, rendering the battery incapable of accepting a charge. Instead, recharge the battery as soon as you notice a drop in performance.

So You Think That's Strange...
If these DIY myths seemed a bit mundane, rest assured that the truly weird is out there, lurking on the fringes of the believable. Take for example this classic case of “more is not better” from 2003, when a San Diego man blew up his home by incorrectly using “bug bombs.” He reportedly set off 19 such devices in an effort to exterminate all of the insects in his house. A pilot light ignited the released gas, resulting in a nasty explosion that lifted the house from its foundation. Considering that each bug bomb was rated for a 700-sq.-ft. area and the house was a mere 470 sq. ft., it was lucky that no one was home when the explosion occurred.

My favorite fringe tale involves the use of stud finders in a rather unorthodox way. In 1996 California podiatrist Roger Lier announced that he had successfully used the tool to locate “alien implants” in two people brought to him by hypno-anesthesia therapist and abduction researcher Derrel Sims of Houston, Texas. A quick Google search revealed more than 500 sites that discuss the events and the supposed validity of this “discovery,” so I’ll leave it to you to do your own research and draw your own conclusions. As for me, I bought new batteries for my stud finder, just in case.