I repaired some holes in a wall that is to be wallpapered, and then
started applying "Shieldz" to provide the proper surface for the
wallpaper -- and now, an hour or so later, I find that the drywall
compound is lifting up and falling off at the nicely tapered edges. The
dry-wall compound has had a couple of days to dry.
What have I done wrong?
On Sat, 9 Jul 2016 15:25:16 -0400, "Percival P. Cassidy"
I'm not familiar with this product, since I dont use wallpaper. However,
it seems to me that if this product was applied according to the
instructions, then your joint compound was not applied properly. Joint
compound will come loose and fall off if the wall is saturated with
water, but should not come off from giving it a coat of paint or
applying anything that gets it slightly wet for a brief period of time.
On Sunday, July 10, 2016 at 9:44:21 AM UTC-4, John G wrote:
Except that he says it's the drywall compound that is apparently lifting
off the drywall board at the tapered edges, not the paint lifting off.
Plus I thought Shieldz was a primer. IDK, I've never seen this happen.
If you don't remove all the dust from sanding, that could affect the
paint not sticking, but if it's actual pieces of drywall compound coming
off, IDK. What kind of drywall compound was used?
Dunno'; never used the product. The Tech Data sheet doesn't say
anything terribly much on new drywall; does say plaster must cure 90
days before using the product. I'd guess the two days wasn't long
enough, but I'd contact Zinnser and ask what happened/how to fix/prevent.
My guess is that the water base Shieldz transmitted enough water to the thin
areas of compound to turn it back into its original state. If that is so, I
wouldn't expect it to fall off though, just stay where it is and dry again.
A coat of shellac before Shieldz would solve the problem.
On Sunday, July 10, 2016 at 10:20:08 AM UTC-4, dadiOH wrote:
Drywall compound is not supposed to turn back into it's original state
with the application of some water, certainly not with the amount of
water in some primer that dries in 15 minutes. AFAIK, it's like concrete,
ie it undergoes a reaction and it's not simply water going out and it's
ready to accept water and return back to original. The problem seems
to be with whatever the joint compound used was and/or the condition of
the drywall board. We don't know what kind of compound, board, etc.
New or had they been sitting around, surface possibly soiled, etc?
That's a good point; it's quite possible _any_ water-based primer
would've resulted in the same result if the problem was really one of
adhesion only...which isn't a bad supposition; one would presume the
product itself doesn't cause rampant such failures or wouldn't be
around...while I think Zinnser is one of the "pretty proud of
themselves" products in general, they generally do perform.
On Sunday, July 10, 2016 at 11:06:27 AM UTC-4, Terry Coombs wrote:
Well, I did include this part:
"is not supposed to turn back into it's original state
I know it's not totally hard forever like concrete, but I thought from
experience that when it's dried on tools it's been a pain to get off,
even when scrubbing and using hot water. But it does come off at least
under those conditions with some work, so maybe you're right, with
enough water and enough time, maybe it will go fully plastic again.
But the water exposure the OP had is very minimal and if what's happening
is normal, then you'd have that problem with any latex paint, right?
I just started a test. I knew where there were a couple globs of it left
on a piece of cardboard from a home project here. I took two small
pieces, they are soaking in water. I'll check at 15 mins, see what happens
On Sunday, July 10, 2016 at 11:47:03 AM UTC-4, trader_4 wrote:
I missed the 15 min check, but at 30 mins the two pieces had softened
up and working them between my fingers, I did get it back to consistency
similar to original. These were about nickel thickness flat pieces.
It was the pre-made, normal dry speed stuff.
So it does soften up a lot more easily than I thought. But obviously
this shouldn't be the problem the OP is having, because if the minimal
water in latex paint can cause it to come off, everybody would have
I'm left thinking it's something to do with either the mud used or
the surface of the board, which we have no info on.
You could try redoing the drywallcompound, and then extra dry it using a he
ated hair dryer. You could also use the hair dryer to dry whatever type of
oil-based primer you put on over the drywall compound before using anythin
g related to water on the patches.
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