# AP vs Lightweight vs Topping



## Seven-Delta-FortyOne (Mar 5, 2011)

My understanding:

AP is the strongest, but most susceptible to shrinking. I personally haven’t had a ton issues with shrinkage, but I try to not apply it too thick either.

I’ll go through and patch any big holes the day before with 30 minute hot mud.

Lightweight is easier to sand, but a little softer than AP. 

Topping dries the hardest, it’s the most difficult to sand, so it’s best for spray texture, as it makes for a durable finish.


Drywall gurus, is this correct?


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## Oh Kay Carpentry (Dec 30, 2021)

The hardest part is that every region has different products with different names. Sounds fairly correct, but I'm not a drywaller. AP has a lot more glue and is for sure heavier. Lightweight is just lightweight AP IMHO. I would have to disagree with topping; the topping coat is smoother and easy to sand. I wouldn't say it is hard at all.


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## Oh Kay Carpentry (Dec 30, 2021)

I personally use USG products in these steps:

1) Durabond 90 = Prefill joints (if you do that, it is recommended by USG)
2) Taping = If I am doing a lot of taping.
3) Plus 3 or Total = all other coats
4) Easy Sand 90 = for when I need quick set hot mud. This dries hard as snot and is NOT easy to sand. Don't use hot mud over AP.


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## avenge (Sep 25, 2008)

I can't stand Plus 3 I use CertainTeed Rapid Coat for lightweight.


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## rrk (Apr 22, 2012)

Plus 3 is nearly useless and when did easy sand become hard to sand?


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## JFM constr (Jul 26, 2014)

ok ,i need info - what does AP mean .
i guy used topping as regular mud on one of my jobs .guess he was tired and oops .anyhow it all peeled away .i went back in removed and replaced it . 
Found a 5 and 10 min mud at home epot .Super for fast patches .I keep some in the truck .
Amazon.com . from your post I "think" you might be doing small batches .This makes a perfect mix which is real nice to work with . no clumps or bubbles .
This can be helpful for one shot patches .
i am a remodelor not a drywall professional .


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## rrk (Apr 22, 2012)

AP is all purpose (green lid)


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## tjbnwi (Feb 24, 2009)

JFM constr said:


> ok ,i need info - what does AP mean .
> i guy used topping as regular mud on one of my jobs .guess he was tired and oops .anyhow it all peeled away .i went back in removed and replaced it .
> Found a 5 and 10 min mud at home epot .Super for fast patches .I keep some in the truck .
> Amazon.com . from your post I "think" you might be doing small batches .This makes a perfect mix which is real nice to work with . no clumps or bubbles .
> ...


All purpose

Tom


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## JFM constr (Jul 26, 2014)

ahhh ,now that makes total sense . thats the stuff that gets moldy due to how often i use it or need it . 
growing up I would watch my brother mix a bag of 45 min mud in 5 gal bucket . I was wise to get out of the way as he spred that out fast .


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## Big Johnson (Jun 2, 2017)

rrk said:


> Plus 3 is nearly useless and when did easy sand become hard to sand?


Easy sand setting mud is pretty tough to sand but not as bad as full on durabond so it gets to name itself easy sand.


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## Seven-Delta-FortyOne (Mar 5, 2011)

Most of my drywall jobs are between 1000-5000 sf. So not huge jobs.

Talked to my drywall supplier today, and apparently it isn’t quite so cut and dried.

Different brands have different characteristics and names.

I use AP for most everything. Evidently that’s just fine.

Topping is not to be used for first coat however.

They have taping compound, and pre-mixed texture, and bagged textures…

More crap than I need to get into.

I do maybe 2-4 drywall jobs a year.


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## Tinstaafl (Jan 6, 2008)

Seven-Delta-FortyOne said:


> I use AP for most everything. Evidently that’s just fine.


I dunno, maybe there's a reason it's called AP?  

Same here. If all I did was drywall, I'd probably be really into all the different mixes. Or committing suicide.


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## rrk (Apr 22, 2012)

Big Johnson said:


> Easy sand setting mud is pretty tough to sand but not as bad as full on durabond so it gets to name itself easy sand.


Should be named Easier Sand


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## A2Zcontracting (Jun 15, 2019)

You've got the general gist but there's a bit more when you get into it. AP can pretty much handle everything if you just want one bucket to carry around but it's not the most efficient. "Topping" is a somewhat loose term as it can refer to mud for skimming, finish coats, or texture but there are several different formulations depending on the finish you're going for. The important thing to know with topping muds is that they don't have the glue in them that the others do so never use them to tape. 

Other important things to remember, hot muds don't shrink but the whole "easy sand" label is a total lie. Its only "easier" to sand compared to plaster. Topper is the easiest to sand but lightweight APs are pretty easy to sand as well. Hot mud is the strongest but by far the toughest to finish with unless you're doing heavy hand textures that don't need to be sanded. Also, premixed muds and mesh tape aren't a strong combo IMO but I don't think mesh tape ever serves a purpose past rough patchwork. Paper beats plastic every time in my book.

I do a ton of reno work, lots of water damage repairs and patches. Typically 2-8 sheets per job and roll like this on most jobs. Hot mud to prefill, tape/cornerbeads and skim/float. Then lightweight to skim, finish and feather out edges a bit. This way I can get all my mud done the same day. Then come back when it's dry to sand and/or spray texture. I buy hot mud depending on the job size (small jobs all 20 minute, larger jobs 45-90 minute) then use lightweight TnT to finish. 

For your size of jobs you could do just AP for everything as long as you're working a large enough area where you're not doing multiple passes the same day. Your wrist will thank you to switch to lightweight after you tape though. Same thing if you use topper for your final skim. Makes sanding a bit easier. Try some other stuff out on your next drywall job. You might be surprised.


Sent from my SM-G781U using Tapatalk


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## Big Johnson (Jun 2, 2017)

Seven-Delta-FortyOne said:


> Most of my drywall jobs are between 1000-5000 sf. So not huge jobs.
> 
> Talked to my drywall supplier today, and apparently it isn’t quite so cut and dried.
> 
> ...


A 5000 square foot drywall job is pretty big, do you use any auto tools or do everything manually?


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## Seven-Delta-FortyOne (Mar 5, 2011)

I have a PanelLift, banjo, drywall screw guns, porter cable power sander, rolling scaffold, hopper sprayer.

5000 was my biggest, don’t do a lot of that.

Im resisting buying a texture sprayer and bazooka, because then I’d be committed to doing drywall. 😳🤣


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## Big Johnson (Jun 2, 2017)

Seven-Delta-FortyOne said:


> I have a PanelLift, banjo, drywall screw guns, porter cable power sander, rolling scaffold, hopper sprayer.
> 
> 5000 was my biggest, don’t do a lot of that.
> 
> Im resisting buying a texture sprayer and bazooka, because then I’d be committed to doing drywall. 😳🤣


I bought a hardly used bazooka for less than half price, haven’t used it but it was too good a deal to pass up. If the housing market tanks I might have to do drywall work.


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## JFM constr (Jul 26, 2014)

Seven-Delta ,I was thinking you were an electrician mainly .With alot of commercial work .
Not so though is it. Are you more of a remodelor .?


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## Seven-Delta-FortyOne (Mar 5, 2011)

I’m all over the map. 🤣

Electrical, framing, and concrete/foundations are mostly what I’m trying to focus on, although I’m a full-service remodeler.

Ive done everything in house for a long time except for HVAC and roofing.

Smaller jobs and pretty much all the houses at the ranch I’ll do a lot more in house. 👍


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## GCTony (Oct 26, 2012)

FWIW: The drywall company that does or bigger work uses Proform red top, mid weight (National Gypsum) for everything. I've never seen USG mud but the rock is USG.


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