Easi Fill sinking in corner after painting?

[dondo]

Hello! I've been repairing a few blown tapes in a 3-year-old house. But after painting, it looks like the jointing compound has sunk?

I did 5 stages of compound:

1. Pre-filled gap in the corner with Make Good jointing compound (very similar to Easi Fill)
2. First layer to bed the tape into (metal corner bead tape)
3. First layer on top of the tape
4. Second layer on top
5. Third layer on top
6. Sanded
7. Sealed/primed with Zinsser 1-2-3
8. Two coats of Dulux Diamond Matt

I let each stage of compound dry at least 24 hours. The three layers on top I feathered out further each time. After sanding, it was perfectly smooth and feathered in.

But after painting, it seems to have sunk. You can see in the picture where there's a ridge - the compound is set further back. I feathered out much further than this ridge - it's roughly in the middle of as far as I feathered out to.

Any idea what has happened here?

 

[opps]

Is it possible that the moisture in the paint has resulted in something expanding (rather than shrinking)?

 

[dondo]

Is it possible that the moisture in the paint has resulted in something expanding (rather than shrinking)?

Good point. I applied the compound quite thinly and let it dry for ages, so it doesn't make sense that it would have shrunk.

Maybe Zinsser 1-2-3 isn't suitable for sealing easi fill type compounds?

 

[opps]

Perhaps use Zinsser BIN (or oil based UC) over the area first, then apply the easyfill.

 

[dondo]

Perhaps use Zinsser BIN (or oil based UC) over the area first, then apply the easyfill.

Will do next time. Maybe I applied the 1-2-3 a bit too thin as well.

I had heard people say they just put a mist coat of emulsion on top of easi fill so I thought it would be fine but clearly not!

 

[opps]

The mist coat on the easifill might have caused the a tape to blow slightly. Can you detect any bounce?

 

[dondo]

The mist coat on the easifill might have caused the a tape to blow slightly. Can you detect any bounce?

No, it feels pretty solid where the tape would be. That was my first thought as well. And the ridges feel hard as well, so it's not the paint bubbling, but the shape of the easi fill below.