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All about 3M Dual Lock

Superlock closeup

Everybody knows about Velcro. This useful material, especially in its self-adhesive form, is an old RVer's standby. But Velcro has a few drawbacks. It isn't very strong—you don't want to mount anything that weighs more than a few ounces with it, unless you use a lot of Velcro. And its self-stick adhesive can lose its bond in hot weather. I've seen Velcro-attached items simply ooze their way off the wall in an Arizona summer.

That's where 3M Dual Lock tape comes in. This stuff works like Velcro, but it has four times the gripping power—and its self-adhesive backing won't let go, even if the temperature soars into the triple digits. Dual Lock doesn't use hooks and loops like Velcro. Instead, tiny plastic "mushrooms" interlock with an audible snap. Unlike Velcro, any piece can mate with any other piece.

Dual Lock comes in a choice of black or clear (I prefer the clear for most purposes) and in four types: 170, 250, 400 and Low Profile. The numbers refer to the number of mushrooms, or what 3M calls "stems," per square inch: Type 170 has 170 stems per square inch, Type 250 has 250, and so on. The Dual Lock you'll find in local stores is mostly type 250, which is good for all-around use. Like typical Velcro, two pieces of standard Dual Lock total about a quarter inch in thickness.

Low Profile Dual Lock is different: it has about 700 stems per square inch, and they're short, tiny ones, so it makes a much thinner joint: two pieces add up to only about a tenth of an inch in thickness. Of course it doesn't have the holding power of standard Dual Lock, but for small, lightweight items like clocks, timers and thermometers it's ideal, and its low profile means that the item you're mounting doesn't stick out as far from the wall.

Dual Lock

Of course, as with Velcro, to ensure good a bond you must clean your surfaces with alcohol before applying Dual Lock. I find rubbing alcohol indispensable for this kind of cleanup task. In the first six months I owned Gertie, I nearly used up a whole bottle of the stuff!

Because Dual Lock grips so powerfully, you should use it sparingly until you're familiar with its holding power. If you lay a 1" x 3" strip on a veneer surface (such as the woodgrain paneling used in many RVs) and then try to pull off an attached object, you stand a chance of pulling off the outer layer of veneer instead! In general, you'll want to use much smaller pieces than if you were using Velcro.

If you expect to be moving things around, you might want to consider the Command Adhesive version of Low Profile Dual Lock. Like other 3M Command Adhesive products, it can be removed without damaging the surfaces it's adhered to, simply by stretching its tab until the adhesive lets go. The drawbacks are that it doesn't have as much holding power as standard Dual Lock, and it only comes in small 3/4" x 2" pieces.

Standard Dual Lock can be removed, however, if you're careful. Lift one corner, grasp it with a needle-nosed pliers (something every RVer should carry) and slowly roll or peel it back. In most cases it will come off cleanly, leaving no adhesive residue. Warming it first with a hair dryer will help it come off more easily.

Applying Dual Lock step by step

To ensure a good match between the two pieces of Dual Lock (and this applies to Velcro too), here's how to proceed:

  1. Clean both surfaces with alcohol and wipe dry before you start. Don't use Goo Gone, Goof Off, kerosene or similar solvents—they do a good job of cleaning, but they leave behind an oily film that guarantees you'll never get a good adhesive bond to that surface!
  2. Lock the two pieces of Dual Lock together.
  3. Remove the backing from one piece and adhere the joined pieces to one surface.
  4. Finally, remove the other piece's backing paper and bring the two objects together. Make sure your positioning is correct—you only get one chance to do this right!

This procedure guarantees perfect matching of the two Dual Lock or Velcro pieces, since they are correctly aligned from the very start.

Shave and a haircut

One more Dual Lock tip: there may be occasions when you need to use a large area in order to get a good bond to the surface you're mounting on (e.g., with textured wallpaper, polyethylene plastic or raw wood), but don't want a correspondingly powerful gripping strength because it would make the attached object too hard to remove.

Shaving Superlock

In a situation like this, take a single-edged razor blade and shave off some of the tiny bristles on one (not both!) of the two mating pieces of Dual Lock. Removing a third to a half of the bristles will reduce the gripping strength, while still leaving a large adhesive area to ensure solid mounting. It's best to start by trimming a third of the bristles; then test the grip and see whether you need to remove more. Cut the bristles as close to the base as you can, so the stubble won't get in the way of latching. Remember, only trim one piece—not both.

Where can I get this stuff?

Radio Shack stores carry it under the "Superlock" label: ask for part number 64-2363 (clear) or 64-2360 (black). Either one gets you a pack of four 1" x 3" strips for about three bucks. I found 3M Dual Lock in my local Target store's hardware (not stationery!) department for about the same price, also in packs of four 1" x 3" strips. A more economical route to buy is to buy it by the yard from an online reseller such as iTapestore, which offers all types of Dual Lock tape in a choice of widths.

Superlock

You may have to do a little digging to come up with this stuff, but it's well worth the effort. In a majority of applications where you'd use Velcro, Dual Lock does a much better job.


Note: If you like these tips, you'll love the new "Eureka!" It has hundreds of good ideas for your RV, including many previously unpublished tips and projects.

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