Perfect 90 inside corner hump

Old 05-11-17, 08:33 PM
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Perfect 90 inside corner hump

Thanks in advance for any help.
I'm a first timer taping walls. I practiced on one inside corner in the garage with perfect 90 tape and it came out fine.
When I did one in the hall, after drying there was a vertical hump on one side up and down most of the tape.
First, not sure how this occurred. Too thin mud?
Second, how can I fix it? Skim the wall? It's probably 1/4" high. Smash it down to break up the mud and try to repair it? Chip the whole corner out and start over?
I used 90 min setting compound.
I'd post a pic but I don't know how...
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Last edited by Blaze626; 05-11-17 at 08:48 PM. Reason: Attempt to add pic
Old 05-12-17, 02:58 AM
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Your second coat can cover it. Don't cut the tape, or you will negate its purpose of keeping it all together. When installing inside corner tape, I find this an invaluable tool to have. Wal-Board Tools 4 in. x 3.5 in. Inside Corner Tool-82-032 - The Home Depot
Old 05-12-17, 03:34 AM
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The only time you want to cut the tape is if you have an air bubble under it. Don't get obsessed about having a perfect 90 corner - houses are never perfect. The main thing is to get it looking decent. It's not like folks will bring out a square to see if the corner is perfect, it just needs to look good

I prefer using a regular drywall knife although it takes practice to be able to mud both sides wet. Many swear by the corner knife Larry provided a link to, a few swear at it .... I'm one of the latter
Old 05-12-17, 03:36 AM
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Spread your mud out 6 to 8 inches and hump will disappear.
Old 05-12-17, 06:02 AM
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The bead didn't get pushed tight to the wall on both sides. You need to try and squeeze out the mud that's behind the tape as you bed it. Maybe your mud was a bit thick... It might help if your mud is a little more thin / wet. Not thin like pancake batter... just a little thinner than usual.

I agree more mud and a wide knife will make that disappear.
Old 05-12-17, 09:30 AM
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I think X meant the 'tape' didn't get pushed tight to the drywall on each side

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