Patching and Plastering - Joint tape required?

I'm an amateur but have done a great deal of drywall and have always used the fiberglass mesh or paper tape. A handful of times I've done the mudding without the mesh or tape, and it seems to do just as well in the short term and long term. Exactly why is tape or mesh necessary?

Welcome to the forums! Thusfar you have been lucky. The tape (paper preferred) helps to keep the joints you are covering from expanding, making an obvious crack form in the wall/ceiling. I wouldn't take on a large project without using tape, whether you use mesh or paper. Mesh, of course won't work well for ceiling to wall transitions, nor for wall to wall transitions, only flat surfaces. It tends to not lay square in those transition corners like paper tape will.

Thanks Chandler.

Regarding the mesh, I've found that if you take the taping knife and force it into the corners (wall to wall or wall to ceiling), it works just fine. I'd use the paper more but have had such crappy results (skill related I'm sure :)) over the years.

I never seem to get out of a project without 2 or 3 "bubbles" appearing under the paper.

Do you thin your j/c any? I generally thin my mud a tad and mix it well. That makes it slide better and if you have a full coat of mud under the tape, you shouldn't have any bubbles..... and if you do get bubbles, you can cut them out and redo, sometimes without adding more tape.

Thanks Marksr,

No, I've never thinned the j/c, but I do "stir" the stuff on top with the taping knife to make sure I get a moist scoop.

Thanks for your advice guys. Even though I hate it, I guess I'll keep using the tape/mesh. :)

You can even use a paint mixer on a drill to make ready mix super creamy. Without mixing, even when you get a farily fresh pail, it can behave like cream cheese and make a certain noise when you scoop it. It can sound "gooshy" and can have air entrained in it. But when you paint mix it, it just gets more creamy and real easy to work with, even without adding more water. The first time I tried this, I remember asking myself how that could be, since I never added water.

You should thin the mud with some water and mix it up very well with a drill and mixer paddle to get it to a creamy consistency as was suggested. I have been doin drywall professionally for a good many years and would never do a drywall job without taping the joints with PAPER tape. I have used mesh for small patch jobs, but that is it. The hint on cutting out bubbles is very good and this will work.

Why paper instead of mesh? Is it preference, speed, thickness of the mesh, less cracking, or what?

The thing I like about the mesh is I can put all the mesh up at once and then do the j/c. With tape, I have to put a layer of j/c, put down the knife, pull out the tape, unroll tape & tear, put tape away, pick up knife and apply more j/c. Plus, I've never had bubbles with mesh and always get at least one or two bubbles with tape.

I know some of y'all are professionals, and I'm not trying to insult anyone's professional knowledge. I'm just asking genuine questions and trying to figure out WHY one method is preferred over another. Thanks again for all your advice.

There are a lot of failures related to the 'sticky' mesh tape. Basically it's bad to loose it's adhesion. I've also seen joints that have rolled up a little where the 'sticky' tape was used. Common practice is to use a setting compound [like durabond] over the mesh tape to keep it in place.