So I have a hole about 20" x 15". I cut a piece of drywall and mounted it using a couple wood slats in the standard way. Now I just need to mud. For such a small jab, do I still run the risk of the mud cracking over time?
fishlakeguy
Yes, the paper is the strength of the patch. LOTS of mis-information given here....
Dry mix mud [bag] will "set" like concrete does, it doesn't just dry like the pre-mixed in the buckets will. The number on the bag indicates the approx time in minutes you have to work with it before it sets up, [5-20-45-90].
There is also different mud for different coats. First coat generally has a gooey glue mix and is meant for paper tape. Topping or top coat is for subsequent coats as it is much easier to sand smooth than first coat.
I use premix first coat and let it dry for at least 2 days before applying the next coat, as it is generally the thickest coat. We use paper tape on EVERY seam, even a short 2" cut around an outlet.
I use the "setting type dry mix" if I need to do a quicker job and coat it 2 or 3 times in one day, such as a small repair job. If I need to keep coming back everyday for a week , it is gonna be expensive. Dry mix is more difficult to sand, so you need to be good with the broad knife to minimize sanding.
Good luck
Anonymous
I never use tape or wood slats. I learned a trick years ago that is permanent and foolproof.
Clean up the hole square and neat, straight lines on all sides. Measure the hole's dimensions and cut a piece of sheetrock 4 inches longer on length and width. Turn oversized sheet rock patch over, and mark the size of the hole centered on the back. Score the back paper to each edge. Now snap the sheetrock along a score and peel the sheetrock from the face paper. Repeat on all four sides. You will have a patch that fits the hole with a 2" paper flange all around. Now butter edge of hole with compound, and two inches around edge of the hole. No missed spots. Butter edge of patch as well.
Gently place in hole with patch flush to wall, draw your joint tool away from center of patch scraping out excess joint compound. Working carefully, the extra paper acts as paper tape but will not make an obvious "LUMP" or "BUMP" in the surface of the wall. As long as the patch is flush or slightly recessed and not proud of the wall let it dry, tomorrow give another skim coat and feather the patch. DON'T make a pregnant wall.
DIY Everything!
For a smaller hole in the middle of a sheet I would say no. But this is a fairly good sized hole. You really should cut your hole up to the next studs and attach 2x2's to the studs for your patch piece to be attached to (see the web page cited below). Then for sure you will tape since at least one edge will be along a seam. This can be done yourself if you are willing to take your time and place enough light coats.
Dan B
I like the fiber tape more than the paper tape, especially for repairs such as yours. It does a better job of keeping the mud from cracking. So, my answer is yes - it's cheap insurance to avoid doing the job over again.
elhigh
Anything over a foot long, I tape. It adds about three minutes to the job and ensures a good result, as opposed to running the risk of the job developing a crack. Why not invest the effort to do it right the first time?
Usually I'll spend a few extra minutes chamfering the edge of the patch and the hole to minimize the bump. Done right it means you don't have to feather out quite so far, but still - I feather out pretty far regardless, just to avoid having to sand.