Lake City Drywall & Paint
Services & Products
Joint Tape & Compounds
Drywall finishing commonly called tapping is simply the process where the screws, seams, and corners are concealed with three coats of joint compound then sanded to a smooth finish ready for paint, texture or wall paper. The first coat is called the embedding coat, the second is the filler coat and the third is the finish coat. Each coat is applied a little wider than the previous coat with the edges feathered to provide a smooth surface. In this section I’ll explain the different types of taping knives, joint tape and joint compounds that I most often use to finish drywall.
The mud pan is a rectangle stainless steel or plastic pan that is used for the mixing, and applying of joint compound. Mud pans come in a few sizes 10”, 12” and 14”, most drywall finishers use the 14” stainless steel pan.
Taping knives are available in many sizes, shapes, prices vary depending on the manufacture and where purchased. Taping knives range in size from 1” to 24”, when purchasing a taping knife make sure that the blade is stiff but flexible and that the handle fits comfortably in your hand. The most common taping knifes that I use is the 6”, 10” and 14” taping knife. The six inch taping knife I use for the first coat to apply joint compound to all screw heads, tapered-edge seams between panels, butted seams, inside and outside corner bead. Once the joint compound and joint tape is applied I then use the 14” taping knife to smooth and feather the seams. I use the 10” taping knife to apply the second coat of mud using the same process as in the first coat to apply, smooth and feather the joint compound on the tapered-edges between panels, butted seams and outside corner bead. Once the first two coats are dry I use the 14” taping knife to apply the finish coat to all seams and outside corner bead.
Joint tape is used in the finishing process to reinforce tapered-edge seams, butted seams, inside corners and to repair damaged drywall. Joint tape is available in two types pre-creased paper tape and self-adhesive fiberglass mesh tape.
Paper tape is manila in color and has a crease down its center and is available in 2 in. wide and 250 ft. to 500ft. long rolls. Paper tape can be used with all types of joint compounds, all seams and inside corners as well as used to repair damaged drywall. Paper tape has some advantages over mesh tape: paper tape is stronger and resists stretching and wrinkling more than mesh tape. Paper tape can be used in corners due to its crease down the center and paper tape is much cheaper than mesh tape. Disadvantages to using paper tape is that paper tape can develop bubbles under the tape when not enough joint compound is applied and paper tape is more time consuming than mesh tape.
Fiberglass mesh tape is becoming more widely used than paper tape mainly because of its ease of use. There are two types of mesh tape self-adhesive and non-adhesive with the self-adhesive being more commonly used. Mesh tape is white in color and comes in 1 1/2in. or 2in. wide and 300ft. to 500ft. long rolls. Mesh tape can be used with all types of joint compounds, all seams and inside corners as well as used to repair damaged drywall. Most often mesh tape is used on tapered-edge seams and to repair gapes that are more than ¼” wide. Advantages to using self-adhesive mesh tape, is that it is faster to install then paper tape and resist the development of bubbles under the tape. Disadvantages to using mesh tape is, not as strong as paper tape, prone to wrinkling and shrinking, does not work well in corners and cost more than paper tape.
When you go to your local hardware for joint compound you are faced many types and kinds, powders and premixed, brands and manufactures, it can all be very confusing. All you really need to know is what type, setting or drying once you know that the rest is just personal choice as to which brand, premixed or powered. I’ll describe the most common types and kinds in each of these categories Drying and Setting types.
Drying-Type Joint Compound is the more popular type it comes in one gallon and five gallon buckets and boxes. It is available in premixed and powdered forms, with the premix being the most popular. The premixed is ready to use right out of the bucket (hit: you should use a mud paddle and a ½” drill to remix the compound to factory consistency, this will allow the compound to spread more easily and smoothly). There is very little waste with the premixed as the bucket can be resealed and used latter.
Powdered Drying-Type joint Compound works just like the premixed the only difference is that it has to be mixed with water. The advantage to the powdered form is that it can be stored indefinitely as long as it is kept dry.
There are three kinds of Drying-Type Joint Compound used on most jobs. The first is the Taping Compound it is used on the first coat to embed the joint tape and as a filler for the second coat. It is a strong, little shrinkage and doesn’t crack. The second kind of Drying-Type Joint Compound is the Topping Compound. This kind of compound is used as the finish coat it is easy to work with, dries fast and is easy to sand. The third kind of Drying-Type Joint Compound is the All-Purpose Joint Compound this kind of compound can be used for all stages of the taping process and is the most popular and most convenient of all the joint compounds.
Setting-Type Joint Compound harden by a chemical reaction unlike drying-types that set as water evaporates. Setting-types have many advantages over the drying-types of joint compound. Setting-types harden faster which allows a second coat to be applied before the first coat is dry. Setting-types are available in powered (needs to be mixed with water) form which allows for extended storage, and are usually less expensive. Setting-types have better bonding qualities, less shrinkage and cracking and a harder finish. Setting-types are available in different setting times, 20 min, 45 min, 90 min, and 210 min., I prefer to use the 45 min. for small repairs and the 210 min. as it allows me time to apply the compound to the seams. Disadvantages to using setting-type joint compounds is more waste due to the chemical reaction and the faster setting times the compound begins to set up in your pan making it difficult to work with. Make sure you mix only what you need with the proper setting time that will you enouhgt time to apply the compound before it sets up. Since setting-types have a harder finish this makes it more difficult to sand.