Joint compound edges

I'm not sure what you mean by shiny ridge ??


You don't want any ridge you can feel or catch with your drywall knife. Once you think it's ready for paint, apply your primer and pay attention to how it looks while wet. The shiny wet paint will highlight any areas that need more work.

You don't want to sand a depression into the mud. It looks like it needs a thin coat of joint compound which you would then lightly sand before priming.

I tried doing a thin coat just over that spot. When it dried it was smooth and shiny. Not very porous and hard to sand. Am I maybe putting too much pressure on my trowel and too much of an angle?

First, what type of joint compound are you using?

Second, sanding should only be needed, if at all, after all the mud is applied.

My guess is you started with too much mud and now it is the high point that you keep sanding. Place a long straight 2x4 or 6' lever across that ceiling area and it will show the low areas that need the mud to bring everything up to being close to flat.

Bud

Hi bud,

I'm using Synko CGC DUST CONTROL Drywall Compound, Ready Mixed, 13.5 L Pail, thinned down with 16oz of water.

Well, you can control the dust by eliminating 98% of the sanding.
I read their instructions to add water one cup at a time and I'm not sure that is good advice, although I have never used that specific product. Regular 5 gallon pales of USG green or blue lid would take added water by the tablespoon. In my experience, not a pro, it's very easy to get too thin. Not sure if that is related to your "shiny" problem.

Do the long straight edge test and I suspect you will need to feather that spot out considerably to both sides.

The pros will comment on that joint compound.

Bud

Ok Thanks Bud. The spot where I sanded was a lift off in the middle of the wall. No feathering needed there. I just went to deep when sanding.

Make me happy and put a straight edge up there. Wherever there is a bump or shallow the straight edge inspection adds free information.

Bud