Grit fail

The fault is not only with the girt or the pva, you are chemical bonding to the paint on top of the Artex, and how well the Artex has taken to the boards or the lime plastered ceiling.
Seen Artex that has been mixed strong and Artex that is like dead plaster with no strength.
Never had one blown hollow on me, but every time you known you are taking a chance.
 
In this case it’s clear the grit has bonded to the paint but the plaster hasn’t bonded to the grit which is the whole purpose of the grit.
 
Boycie said:
In this case it’s clear the grit has bonded to the paint but the plaster hasn’t bonded to the grit which is the whole purpose of the grit.
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Still goes back to the point about thick overskim and a flexy ceiling proving too much to hold back.

So, yeah, it didn't bond super-well, but at the same time, it's not fair to expect a bonding agent to work total miracles if you've got 5mm of skim and a flexing ceiling.
 
stuart23 said:
Can’t believe I’m having to explain that
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cow dog costume GIF
 
stuart23 said:
When someone says something outrageously stupid and you turn to look at them in utter disbelief, that’s what the cow is doing. Can’t believe I’m having to explain that
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What, no cow gif?

Thing is, it could mean other things, so I wasn't arrogantly assuming I knew. (y)
 
The Apprentice said:
The vast majority of grit fails are due to not mixing the aggregate back in sufficiently. Always a good practice to mix all the aggregate up then remix every so often to stop it settling in the bottom again.
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half the monkeys on here don't do things to manufacturers specs, they make it up as they go along
asking them to perform a simple task like stirring a tub of grit is beyond them
 
The Apprentice said:
The vast majority of grit fails are due to not mixing the aggregate back in sufficiently. Always a good practice to mix all the aggregate up then remix every so often to stop it settling in the bottom again.
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Don't need to with the green cementone (Bostik) one. The grit is suspended in the liquid, it doesn't sink to the bottom.
 
Boycie said:
Don't need to with the green cementone (Bostik) one. The grit is suspended in the liquid, it doesn't sink to the bottom.
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only had one failure with blue grit once on silk walls. Use the green stuff now, but still got to be careful with suction control
 
The Apprentice said:
The vast majority of grit fails are due to not mixing the aggregate back in sufficiently. Always a good practice to mix all the aggregate up then remix every so often to stop it settling in the bottom again.
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Thing is.... I'm not disputing the wisdom of taking the time to mix the aggregate before application, but it does beg the obvious question:

PVA doesn't have grit in it, yet in a large number of cases, multi sticks to it well.

Are you suggesting that if blue grit didn't have any aggregate in it, it would be next to useless?

I'm not trying to catch you out - I feel it's a valid question. Is blue grit 99% only about mechanical key, and far worse performing than PVA in areas with scant aggregate?

In fairness, I'm not generally pointing fingers at blue grit with artex ceiling fails, as I am in the camp that feels there are several factors at play that it would be unfair to always blame on grit failure (thickness of skim + flexing joists, poor artex integrity, vinyl silk having been historically applied to the artex, etc. etc.)
 
MakeItSmooth said:
Thing is.... I'm not disputing the wisdom of taking the time to mix the aggregate before application, but it does beg the obvious question:

PVA doesn't have grit in it, yet in a large number of cases, multi sticks to it well.

Are you suggesting that if blue grit didn't have any aggregate in it, it would be next to useless?

I'm not trying to catch you out - I feel it's a valid question. Is blue grit 99% only about mechanical key, and far worse performing than PVA in areas with scant aggregate?

In fairness, I'm not generally pointing fingers at blue grit with artex ceiling fails, as I am in the camp that feels there are several factors at play that it would be unfair to always blame on grit failure (thickness of skim + flexing joists, poor artex integrity, vinyl silk having been historically applied to the artex, etc. etc.)
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Grit is designed to be used on surfaces with little or no suction such as tiles & smooth concrete for example, and the grit gives the key to enable the plaster to adhere to it. If the grit is dry and does not contain sufficient grit the plaster hasn’t got anything to grip to. With tacky PVA the Gypsum crystals that grow during the setting process can grow in to the PVA.
Hope that answers your question.
 
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