Adhesives: All About Glue
What’s the first thing that comes to your mind when glue is mentioned? Elmer’s glue, carpenter’s glue, you used too much glue once and it made a mess of everything, how about just white glue, a friend whose fingers got stuck together on Super Glue, or maybe you are old enough to remember the white paste in a jar that you used in grade school to assemble colored construction paper! Whatever your memory, if you are old enough to sleep in a bed you have had several experiences with glue.
Believe it or not, when the proper glue is used for a given project (and when it is applied in accordance with the manufacturer’s specifications) the glued joint often will be stronger than other parts of the material. Glue charts are available in better home improvement centers that indicate which glue works best with what materials and which adhesives work best on certain combinations of materials. So, we don’t want you to waste your time trying to remember the almost infinite number of combinations of glue and materials that are available. However, there are some rules of the road that you should be aware of that will get things “sticking and staying” around your house. Sorry, but we DO NOT offer help with wayward spouses.
Here’s what to remember before going shopping. First, first be sure to determine the types of materials being glued – wood to wood, metal to glass, ceramic to ceramic, etc. Another example: real marble and cultured marble are sometimes similar enough in appearance to fool the novice. Making the wrong guess in a glue application could mean having to do the job over and over again. It is important to know whether the glued item will be indoors or outdoors. Outdoor adhesives are water resistant and indoor grades normally are not. Read that last sentence again. Note the words “water resistant”. Water resistant adhesives that are used outdoors may not be “waterproof”. That’s why you will want to look for a waterproof adhesive if the item to be glued will be used under water. Is there such a glue you ask? You bet there is! Where could you use a waterproof glue at home? How about repairing a broken decoration in an aquarium, or a broken shower tile, or even a chip in the kitchen sink.
Your task is only 50% complete once you have chosen the proper glue. The other half of the job involves its proper application. Here again there are a few rules of the road that you will need to follow in order to achieve our famous “stick and stay” connection.
It is pretty obvious that a connection should be absolutely clean. But did you know that an old joint that is being reglued is not clean enough if the old glue remains. To remove it you can use adhesive solvent, a scraper, a heat gun, a hole grinder, a steam iron or a wire brush. Be sure the surfaces to be joined are free of loose particles and old adhesive.
Temperature is another important factor. Glue does not like cold days. Whenever the temperature drops below 70 degrees many types of adhesives will take a great deal more time to harden. Just because the container brags that the product dries in less than an hour doesn’t mean that it will in your case. A Carey Bros. rule of thumb for most household glue jobs: “leave it alone until tomorrow”.
Another factor to consider is the type of connection to be glued Porous surfaces like pottery and the end-cut of a piece of wood should get more than one coat of glue. If the surface is porous a single coat of glue would be quickly absorbed and none would be left on the surface of the joint to form a connection. A loose connection is a risk at best. Trying to use glue as a filler for large gaps will more often than not result in a failed joint. In the case of a wood project for example, wood shavings, toothpicks and an unfinished golf tee, are but a few items that can be used to shim a joint so that it is as tight a connection as possible. Although wedges and shims are great for creating a tight joint, in many instances clamping devises will be necessary. Tape may be OK for some connections, but for most applications a bonafide furniture clamp can make all the difference. Clamp choices are endless and can be used for other household projects. One company offers at folding work table that has a built-in clamping system.
Last but not least, be sure to read the safety instructions on the glue that you will be using many are not only flammable, but explosive as well. In some cases adhesives can be so flammable that it could be wise to turn off any nearby pilot lights. And may all the projects you glue stick and stay stuck!