# knock down on plaster



## 2buckcanuck

:thumbsup::yes::jester:


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## 2buckcanuck

This is a question for the DWC I work for. He actually asked me to ask you guys if you have any secret knowledge, since I always mention this site all the time

We were talking about how KD don't co-operate when going over plaster, or oil base paint. It stays all wet and mushie like, and just smears when trying to knock it down. Other than putting drywall on the ceilings, or coating over it with a layer of mud, do you guys have any secret knowledge on the subject matter. Maybe there's a product on the market that works or something, or someone has a trick to do it:yes:

It will get me brownie points:whistling2:


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## gazman

I think Kiwiman knows the solution to the problem. Good luck getting to know his secret now .


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## 2buckcanuck

gazman said:


> I think Kiwiman knows the solution to the problem. Good luck getting to know his secret now .


No way:blink:

Your pulling my leg, aren't you:yes:


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## Mr.Brightstar

2buckcanuck said:


> This is a question for the DWC I work for. He actually asked me to ask you guys if you have any secret knowledge, since I always mention this site all the time
> 
> We were talking about how KD don't co-operate when going over plaster, or oil base paint. It stays all wet and mushie like, and just smears when trying to knock it down. Other than putting drywall on the ceilings, or coating over it with a layer of mud, do you guys have any secret knowledge on the subject matter. Maybe there's a product on the market that works or something, or someone has a trick to do it:yes:
> 
> It will get me brownie points:whistling2:


I would prime it with gripper first. Then base coat with hot mud let dry for 1 day. Then spray and wipe down. Topping should dry quickly and suck into base coat and not smear or pull off. 

Just a theory


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## gazman

2buckcanuck said:


> No way:blink:
> 
> Your pulling my leg, aren't you:yes:


Maybe.


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## DrywallerDustin

Knockdown is ugly anyway, just do something different.
If the customer is sure they want something ugly that went out in the 70's maybe you could sell them on popcorn...


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## 2buckcanuck

DrywallerDustin said:


> Knockdown is ugly anyway, just do something different.
> If the customer is sure they want something ugly that went out in the 70's maybe you could sell them on popcorn...


Went out in the 70's:blink:, we just got it here:blink::whistling2:


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## SlimPickins

Spray it with a hopper. And use hot mud. Shhh!


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## DrywallerDustin

2buckcanuck said:


> Went out in the 70's:blink:, we just got it here:blink::whistling2:


You've got to be kidding, I thought the only place they did that anymore was California.
I would try spraying it and letting it dry completely, then spray again and knock it down, not sure if it would work, or how it would look, but worth a try, at least if this is a common problem, and it would be quick.
Though my experience with knockdown is limited as I was not yet alive in the 70's, so take it for what it's worth, not much


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## PrecisionTaping

I would think just priming your wall with a fresh coat of primer would seal it well enough that you could knock it down.
If not, spraying it twice like dustin suggested isn't a bad idea.
If you wanna do something cool, do a cross weave pattern.
Horizontal the first spray and vertical the next.
Or vice versa. Just an idea.


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## Mudslinger

Priming works, but I prefer to spray a fog coat the day before I knockdown. If you want a little more insurance put some bonding agent(PVA) in with the mud your fogging with. We do it all the time, and it knocks pretty much the same as new drywall.:thumbsup:


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## fenez

2buck, because the surface is sealed will oil the compound can't shrink in which means it takes longer to dry which is why it stays mushy, while I've never been asked to do knock down because everything here is completely smooth finish always, but when I do renos in old plaster homes that require a veneer or skimming I encounter the same problem, how I handle it is to apply a bonding agent to the surface first.


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## 2buckcanuck

fenez said:


> 2buck, because the surface is sealed will oil the compound can't shrink in which means it takes longer to dry which is why it stays mushy, while I've never been asked to do knock down because everything here is completely smooth finish always, but when I do renos in old plaster homes that require a veneer or skimming I encounter the same problem, how I handle it is to apply a bonding agent to the surface first.


I notice a few of you guys have said a bonding agent, have you guys got some product names. I never had to use it before, but I heard with the veneer plaster, they made some product called red top something something that you could apply to regular drywall to make the veneer work. and what does the PVA stand for.

I don't do the spray that much, we have 3 spray crews that do it full time. I was doing a side job, and the subject of spraying the plaster ceilings came up. The home owner was buying another house done in plaster, and wanted his ceilings done. Thats when I asked the DWC I work for if he wanted to do it down the road, and the subject switched to ,,,cost too much, half to drywall or coat it out so,,,, thought you guys would know:thumbup:

And our spray guys prime out all the ceilings here first, and then spray, so they know that don't work.

Funny thing is, I passed the spray job to the DWC I work for on my little side job (big bosses brother whose our foreman). Stopped in to collect the money to night since he sprayed it today, and the home owner was not keen on paying for his spray job. Didn't like how it did not match the rest of his spray in the house. That means I get to rub it in his face tomorrow,,, maybe I should back charge him or something, or hold his money for 90 days


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## mudslingr

Polyvinyl acetate. It's just glue 2buck. A bottle of Elmer's should do the trick.


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## Mudslinger

PVA is nothing special, just ordinary Elmers glue. I've heard from old school plasters that plaster bonding agent is nothing more than watered down PVA that's colored so you can see where its been applied.


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## Mudslinger

mudslingr said:


> Polyvinyl acetate. It's just glue 2buck. A bottle of Elmer's should do the trick.


Beat me to it!:yes:


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## mudslingr

Mudslinger said:


> Beat me to it!:yes:


Glad you could confirm it :thumbsup: Never did this myself but saw it done about 14 years ago. Guy had a pail of Elmer's and rolled it on. Heard from the boss later in the week that it worked real well. Go figure !:blink:


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## Mr.Brightstar

2buckcanuck said:


> I notice a few of you guys have said a bonding agent, have you guys got some product names. I never had to use it before, but I heard with the veneer plaster, they made some product called red top something something that you could apply to regular drywall to make the veneer work. and what does the PVA stand for.
> 
> I don't do the spray that much, we have 3 spray crews that do it full time. I was doing a side job, and the subject of spraying the plaster ceilings came up. The home owner was buying another house done in plaster, and wanted his ceilings done. Thats when I asked the DWC I work for if he wanted to do it down the road, and the subject switched to ,,,cost too much, half to drywall or coat it out so,,,, thought you guys would know:thumbup:
> 
> And our spray guys prime out all the ceilings here first, and then spray, so they know that don't work.
> 
> Funny thing is, I passed the spray job to the DWC I work for on my little side job (big bosses brother whose our foreman). Stopped in to collect the money to night since he sprayed it today, and the home owner was not keen on paying for his spray job. Didn't like how it did not match the rest of his spray in the house. That means I get to rub it in his face tomorrow,,, maybe I should back charge him or something, or hold his money for 90 days


Red top is gauging plaster for putty coat. The red top Has a bonding agent Already added to it in the bag. Bags of Durabond also have same Ingredient. I use plaster weld whenever applying cement. 

On walls with semi gloss Where the mud would slide a round I prime with gripper by Glidden. It's like troweling on sandpaper Grips the mud off the trowel.


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## 2buckcanuck

mudslingr said:


> Polyvinyl acetate. It's just glue 2buck. A bottle of Elmer's should do the trick.





Mudslinger said:


> PVA is nothing special, just ordinary Elmers glue. I've heard from old school plasters that plaster bonding agent is nothing more than watered down PVA that's colored so you can see where its been applied.


Really, just white glue with water:blink:

Well since everyone is talking all smart like in the cussing thread. Which one of you two is going to explain the "PHYSICS" on why that will make the Knock Down work over top of it:thumbup: :whistling2:


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## Mudslinger

I'm saying put the sh!t in your F**king spray, and fog it the day before you knockdown. :whistling2:


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## mudslingr

Physics ? I didn't like gym class. And that other thread makes my head hurt.:yes:


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## Mudslinger

mudslingr said:


> Physics ? I didn't like gym class. And that other thread makes my head hurt.:yes:


LOL, I started reading that thread and realized I just don't give a damn.


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## fr8train

Physics? More like chemistry


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## Mudslinger

fr8train said:


> Physics? More like chemistry


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## mudslingr

:lol::lol::lol:


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## SlimPickins

If you're going to spray or roll anything on the painted surface you might as well just hit it with thinned down taping mud........that'll adhere, and it will give you the "suction" you need to make the knockdown behave the way you want it to.


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## Mudslinger

SlimPickins said:


> If you're going to spray or roll anything on the painted surface you might as well just hit it with thinned down taping mud........that'll adhere, and it will give you the "suction" you need to make the knockdown behave the way you want it to.


That would work for sure, but not as well as a true unaggregated spray for both coats. If the DWC its for is using a spray rig most guys wont change their material for one job, but you might get them to throw some glue in.


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## 2buckcanuck

Mudslinger said:


> That would work for sure, but not as well as a true unaggregated spray for both coats. If the DWC its for is using a spray rig most guys wont change their material for one job, but you might get them to throw some glue in.


I don't know, i think that physics guy slimpickins, could be on to something with the hopper and plain old hot mud. their looking for a one trip solution. Their a large company, so any pre-prep work would not be done by the spray guy, but a taper. I don't even think most of our spray guys even know how to spot a screw..... not joking


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## SlimPickins

Mudslinger said:


> That would work for sure, but not as well as a true unaggregated spray for both coats. If the DWC its for is using a spray rig most guys wont change their material for one job, but you might get them to throw some glue in.


I suppose that's true....we don't have many dedicated texture guys around here anymore, not since the market tanked back in '08, so I made assumptions about how the work would be performed. In that case, as someone mentioned, a fog would be the way to go.........with glue added of course. If the job was big enough, you could run through with the fog and then start all over again with the KD spray in the same day.......although I don't know many texture guys who like to spray when it's warm in the house, which would be somewhat necessary for the fog to dry enough to spray over.


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## Mudslinger

2buckcanuck said:


> I don't know, i think that physics guy slimpickins, could be on to something with the hopper and plain old hot mud. their looking for a one trip solution. Their a large company, so any pre-prep work would not be done by the spray guy, but a taper. I don't even think most of our spray guys even know how to spot a screw..... not joking


In that case I think I would make the taper skim it out with setting compound, then do a knockdown like normal. Knockdown sets up like crazy over dry setting compound.:yes: It would just be way more work for the poor taper unfortunately.


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## Mudslinger

SlimPickins said:


> I suppose that's true....we don't have many dedicated texture guys around here anymore, not since the market tanked back in '08, so I made assumptions about how the work would be performed. In that case, as someone mentioned, a fog would be the way to go.........with glue added of course. If the job was big enough, you could run through with the fog and then start all over again with the KD spray in the same day.......although I don't know many texture guys who like to spray when it's warm in the house, which would be somewhat necessary for the fog to dry enough to spray over.


The collapse was how I was able to get my hands on a spray rig cheap. Took some time to be profitable, but its been worth it in the long run. I thought about the one day scenario, but over plaster you would want the base bone dry. Like you were saying the sprayer would not be happy with the extreme heat lol.


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## SlimPickins

2buckcanuck said:


> I don't know, i think that physics guy slimpickins, could be on to something with the hopper and plain old hot mud. their looking for a one trip solution. Their a large company, so any pre-prep work would not be done by the spray guy, but a taper. I don't even think most of our spray guys even know how to spot a screw..... not joking


What about a blend? I sometimes do a texture with a certain setting mud mixed in, (I have to treat it very carefully). 

If you get your ratio right, it will kick enough to knock down, but not enough to ruin the machine and hoses if you flush them with water. I think this would require some experimentation.....not so much with the ratio (I have that information), but to see if once it kicks it sticks to the substrate. Might still need some glue......although I've found that hot mud over glossy paint (glue added) will still let go in spots if it hasn't dried completely. Once it's dry it's not coming off without a chisel.


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## Sir Mixalot

2buckcanuck said:


> This is a question for the DWC I work for. He actually asked me to ask you guys if you have any secret knowledge, since I always mention this site all the time
> 
> We were talking about how KD don't co-operate when going over plaster, or oil base paint. It stays all wet and mushie like, and just smears when trying to knock it down. Other than putting drywall on the ceilings, or coating over it with a layer of mud, do you guys have any secret knowledge on the subject matter. Maybe there's a product on the market that works or something, or someone has a trick to do it:yes:
> 
> It will get me brownie points:whistling2:


I know I'm late to the party. But I'll post this anyway's. 
Once the room is prepped for knockdown, spray those areas with a light orange peel. Then hit it with the knockdown after OP dries in a hour or so.:thumbsup:


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