It helps to teach yourself "why" you are even using this tape. It's not decoration. It has a structural function just as the foundation of a house does.
· Is it to fill the gap between the two sheets of drywall? ...No.
· Is it to level out the surfaces? ...No.
· It is to create a solid, continuous surface bond between the two sheets that will show no cracks when small shrinkage and settlement movements occur in the future.
So............ Your main purpose is to allow (or "help") the three elements of...
1. The paper on the face of each sheet
2. The tape, itself
3. The mating coat of mud
... to combine smoothly as a unit... adhere to one another... and dry as a hard, solid bridge upon which to build additional layers of finishing compound (mud).
You do this by, first of all, making sure everything will stick together in more than just a physical, surface bond. You are looking for a chemical adhesion. You do not have to worry about creating a substance that will do this. It's already been created, and it's called "mud".
But you DO have to provide the proper environment and application process for it to do it's job correctly and fully.
This means (believe it or not) that you have to provide additional moisture for the chemical elements in the mud to do their thing.
Step one is to mix your taping mud a little on the sloppy side. The consistency should not be like butter or mashed potatoes... but like mashed potatoes with a big hunk of butter mixed in. The way your kids like to do it at Thanksgiving dinner.
Secondly, this mud is laid into a "prepared surface". Too big a gap between sheets, chunks missing from edges, and paper scraped off the surface of the sheet are bad. They draw water out of the mud too quickly, leaving a dry surface that will not glue itself down right. They also provide huge areas for the mud to shrink into, instead of staying where it is needed... up on the surfaces, helping all three elements combine as one sheet. All these problem areas need to be filled with mud, and left to thoroughly dry hard before you begin taping.
Now you can go on to step two. This is the process of spreading a “thicker than necessary” layer of mud down the strip to be covered with tape... and it needs to be wider than the tape that will cover it. You want plenty of mud on there.
Next, we consider water. Do you know some guys even quickly wipe a wet sponge across the joint before applying mud because moist surfaces are that important for good adhesion? I don’t do that, but I do religiously follow this next procedure.
I keep a bucket of clean water at hand to not only keep all my tools wet, but to also moisten the tape before application. After I cut a piece of tape to length, I loosely wrap it around one hand. I dip this hand (with the tape wrapped around it) into the bucket of water for about a half a second. Just dip it in, and pull it out. Then I proceed like you have probably already been doing.
The trick in wiping the tape on is to, one, keep your knife wet, two, tilt it at about a 45 degree angle, three, keep firm (not hard... just solid and firm) pressure against the wall, and four, be certain that you are always squeezing mud out from under the tape as you drag the knife along.
That’s it. I used to also apply some of that excess mud back onto the tape. I’m learning it is better not to. You are now at the stage where you want that tape, mud, and paper to all dry together............... THOROUGHLY. Additional mud on top of the tape right now really does little more than prolong the deep drying process. It often won’t hurt anything, but why add more time?
One more thing. DO NOT start applying more mud until the tape coat has dried all the way. ALL THE WAY.
Try this, and I think you will soon begin to be happy with your taping jobs.
