# Getting brave about Sanding Durabond



## Brohoho (Jun 29, 2021)

I once feared even sanding Easy Sand but it ended up being fairly easy when I tried. Then I bought Durabond because I like its claimed humidity resistance. I don't feel I have to rush to prime and paint it for the shower area. I was super careful at first and applied it perfectly to part of the wall with no sanding required. I sanded it anyway about a week later with a mesh drywall sander because I was curious and it left slight ridges from the mesh so it's at least a little sandable. Tomorrow we'll see if I got too brave. I'm going to try sanding my latest work around the bathroom light and the shower curtain. Maybe I'll try a little orbital sander.

If anyone here creates Youtube videos, how about making a video about sanding Durabond that set and dried? I found no videos that demonstrate what results you will get.

This is what I'll be trying to sand (I have to skim coat it anyway). I didn't have such harsh side lighting during patching because I had the power off and a light shining in from the other room, since I pulled the light fixture out.


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## ClarenceBauer (Mar 4, 2005)

Brohoho said:


> I once feared even sanding Easy Sand but it ended up being fairly easy when I tried. Then I bought Durabond because I like its claimed humidity resistance. I don't feel I have to rush to prime and paint it for the shower area. I was super careful at first and applied it perfectly to part of the wall with no sanding required. I sanded it anyway about a week later with a mesh drywall sander because I was curious and it left slight ridges from the mesh so it's at least a little sandable. Tomorrow we'll see if I got too brave. I'm going to try sanding my latest work around the bathroom light and the shower curtain. Maybe I'll try a little orbital sander.
> 
> If anyone here creates Youtube videos, how about making a video about sanding Durabond that set and dried? I found no videos that demonstrate what results you will get.
> 
> ...


Try something new: Using a spray bottle with water & the nozzle set to a fine mist spray the setting compound with water than trowel smooth there should be no sanding required if you do it this way.
As for the trowel to use use one of the following A Venetian Trowel that is 8" x 3" or A Stainless Steel trowel 10.5" x 4.5".
To use the spray bottle & trowel if you are right handed use the trowel in the right hand mist with left & trowel smooth.


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## Brohoho (Jun 29, 2021)

ClarenceBauer said:


> Try something new: Using a spray bottle with water & the nozzle set to a fine mist spray


I do that (the evidence is in the drip marks). Most of the vertical lines in the photo are in a depression that I knew had to be filled in another coat. They're probably all lower than the surface so it's OK. I think the rest of the mess is from poor lighting and not having a small enough knife. I had to do a lot of curved motions. Areas where I could only go up and down were tight too. I'm expecting a 6" knife. Smallest steel knife I currently have is 10".


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## mark sr (Jun 13, 2017)

You definitely want to add a 6" knife to your arsenal. It always pays to apply the mud as neat as possible! especially with Durabond. I often use regular joint compound for the final coat because it's so much easier to sand.


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## jeffnc (Apr 1, 2011)

You want a 4" and 6" knives to start. But the bottom line is this is overkill for a bathroom. If you have humidity problems so bad that you need Durabond, then you need to fix the humidity issue because it's going to cause other problems. Millions of bathrooms are doing great without Durabond.


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## Brohoho (Jun 29, 2021)

How well do different muds wash out of clothes? Is easy sand easier to wash out than all purpose?


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## ClarenceBauer (Mar 4, 2005)

Brohoho said:


> How well do different muds wash out of clothes? Is easy sand easier to wash out than all purpose?


In the Plaster that is the reason we wore white coveralls it does not all wash out.


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## mark sr (Jun 13, 2017)

Ready mix mud will wash out, setting compounds will flake off and the rest might come out over time. Best not to wear something you don't want to mess up!


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## Brohoho (Jun 29, 2021)

My Durabond sanded like butter using 60 grit "pro grade" sandpaper on my orbital sander. I cut the sandpaper, punched the holes, and glued it to an old sanding disk with a velcro back.


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## mark sr (Jun 13, 2017)

I'm not overly fond of sanding and would much rather pay a little extra care to applying the mud than resort to a power sander. The final coat of mud shouldn't require much sanding if it's applied correctly. My desire to sand less led to my ability to apply the mud neater.


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## jeffnc (Apr 1, 2011)

I ALWAYS have to sand the final coat. I've heard the legends of mudders who can apply it so well it doesn't need sanding, but I've never seen it and it might be an exaggeration. The best thing to so is apply the first 2 coats well, and only use your taping knife to scrape (not sand) any little ridges or nuggets in between. If it's a difficult spot I don't even try to get rid of all little ridges since I know they scrape off so easily.


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## ClarenceBauer (Mar 4, 2005)

jeffnc said:


> I ALWAYS have to sand the final coat. I've heard the legends of mudders who can apply it so well it doesn't need sanding, but I've never seen it and it might be an exaggeration. The best thing to so is apply the first 2 coats well, and only use your taping knife to scrape (not sand) any little ridges or nuggets in between. If it's a difficult spot I don't even try to get rid of all little ridges since I know they scrape off so easily.


If you select the correct material to use there will be NO sanding required'


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## jeffnc (Apr 1, 2011)

ClarenceBauer said:


> If you select the correct material to use there will be NO sanding required'


lol Clarence, the plaster master! Yeah of course if you plaster everything you don't sand. I'm glad you're around to inform us of the older materials, but good luck trying to get everyone to go back to plastered walls again.


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## ClarenceBauer (Mar 4, 2005)

jeffnc said:


> lol Clarence, the plaster master! Yeah of course if you plaster everything you don't sand. I'm glad you're around to inform us of the older materials, but good luck trying to get everyone to go back to plastered walls again.


Jeffnc : The thing about the up dated plaster products is with new technical knowledge things have been made easy' With some of the newer products, anyone that can apply a drywall product can now use the veneer Plaster using the same tools & the end results will be better & smoother. Also deleting some steps which save time & labor. Yes the $$$ cost goes up but the end results are better & any touch up is better & faster.
Also consider that color can be added & looks like marble can be obtained which means NO paint required.


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## jeffnc (Apr 1, 2011)

I accept all that as true, but the fact remains you're not going to get the industry to change, for 3 basic reasons:

- drywall is the entrenched method (i.e. inertia). This alone could be overcome as it has with other changes in homebuilding, but....

- it costs more, which means homebuilders aren't going to do it (maybe in very rare custom situations)

- the standard way is "good enough". As long as you get up to a certain threshold, no one cares if it's better. Yes 2x6s would make for stronger walls, but who cares? Walls built with 2x4s are strong enough. So end results being "better" doesn't matter to hardly anyone as long as drywall walls look good enough.

Additionally, touch up might be better and faster, but now you have a situation where there are 2 different methods are being used, which just complicates everything. More materials stores have to carry, more materials contractors need to buy and stock, more materials they have to understand how to work with, more they need to know about the wall to begin with. It's just not worth it. Even if you convinced me, it's not going to change the standard.

Also, good luck getting the lady of the house to stop shopping for paint colors, lol


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## ClarenceBauer (Mar 4, 2005)

I do understand your position on the products.
Industry standards are not going to change.
Yes the drywall trade took over due to the labor & cost facture.
Yes existing drywall standards are good enough for new construction.
I was looking @ it as a restoration , repair situation "v" new construction & a DIYer is mostly repairs.
I did bid work in the Plaster trade for the first 15 years than I found a veneer system that made the restoration much easer & faster for a higher profit & discovered that I could get more work doing restorations v the new work.
My first project with a Veneer System was in 1997 were I did a sample wall free of charge the owner liked it so well we did the entire house total cost was $ 90,000.00.
The next project was another free wall got the call to do all rooms on the first floor $ 40,000.00.
From this point on the veneer system was the most profitable part of the Plaster trade.
It got to the point that there was one Architect that specified a veneer plaster must be used for the interior plaster repairs & this was on the second oldest operating courthouse in the USA , at this point in time things got wild we could not keep up with the request for repairs both drywall & Plaster.
As of this date the guys I work with are going full speed doing restorations talked to one of them just hours ago they are working for a long time customer that required more work.
Anyone doing repair / restoration work should look into some of these products they could double their profit margin. The photo's in the previous post was the largest project I got @ a figure of $800 thousand just for the plaster work.


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## jeffnc (Apr 1, 2011)

Yeah I can see that for restoration work or individuals looking for a certain look. It's a good niche market I'm sure because there aren't too many who will do quality plaster work nowadays.


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## Brohoho (Jun 29, 2021)

I think the ease of sanding of my Durabond was a combination of the thinner than average mix I use (I like a little slumping when I hold my knife upside down for a few seconds), the spray bottle I use during patching, and the thinner than recommended coats I used (under 1/8"). I can scratch the set Durabond slightly even with my nail after weeks of drying.

correction: it was all purpose that I scratched with my nail...I switched to all purpose because I was afraid the coats of Durabond were too thin.

The plaster in the living room, applied by a pro, is even softer than the Durabond - way too soft. I read that adding too much water could cause that. I guess that's what you get with products that don't shrink. The water evaporates, and the more water there was the less dense the plaster will be when dry. The good thing about that in my case is I should be able to sand the the waves out of the plaster. I have a bid on an electric drywall sander that I'll attach to my shop vac. Then I'll prime it with something thin (without pigment) so it hopefully penetrates and hardens the plaster a little.


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## GCTony (Jul 21, 2021)

ClarenceBauer said:


> I do understand your position on the products.
> Industry standards are not going to change.
> Yes the drywall trade took over due to the labor & cost facture.
> Yes existing drywall standards are good enough for new construction.
> ...


So am I the only one that wants to apprentice with Clarence for a couple weeks, free of charge? I'm pretty good with just about any kind of trowel. I tell people I can teach MOST monkeys to do drywall finishing, it's about learning the "process" Once you learn the methods; you can start building skill.


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## ClarenceBauer (Mar 4, 2005)

Brohoho said:


> I think the ease of sanding of my Durabond was a combination of the thinner than average mix I use (I like a little slumping when I hold my knife upside down for a few seconds), the spray bottle I use during patching, and the thinner than recommended coats I used (under 1/8"). I can scratch the set Durabond slightly even with my nail after weeks of drying.
> 
> correction: it was all purpose that I scratched with my nail...I switched to all purpose because I was afraid the coats of Durabond were too thin.
> 
> The plaster in the living room, applied by a pro, is even softer than the Durabond - way too soft. I read that adding too much water could cause that. I guess that's what you get with products that don't shrink. The water evaporates, and the more water there was the less dense the plaster will be when dry. The good thing about that in my case is I should be able to sand the the waves out of the plaster. I have a bid on an electric drywall sander that I'll attach to my shop vac. Then I'll prime it with something thin (without pigment) so it hopefully penetrates and hardens the plaster a little.


Over watering any setting compound will cause a weak finish , a poor bond & may cause cracking.
Also the chemical setting action will be effected.
Quote from The Gypsum Construction Handbook page # 186. (of my book)
"Do not use setting-type joint compound for thin skim coats."


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## Brohoho (Jun 29, 2021)

I think I'll be buying a Wen 10 amp sander. No pole, but it's more powerful than their models with poles. The manual says:

*USING THE DRYWALL SANDER*
1. Talk to your drywall and explain what’s about to happen to make sure it’s properly prepared.

It's not a big deal, but USG and Goldblatt never got back to my questions and I prefer a company that runs a tight ship. I consider those usage instructions a bad sign.


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## Brohoho (Jun 29, 2021)

Brohoho said:


> The plaster in the living room, applied by a pro, is even softer than the Durabond - way too soft.


I found MFA Plus deep penetration primer that "penetrates the plaster up to 10 mm deep" but it seems obscure so I crossed that off my list.

I found something about vinegar hardening plaster, then all I found was that it dissolves plaster which I didn't really want. Then I read that alkyd primers are good for plaster and I found one (a modified one, I guess, because of the acrylic) that cleans up with water: Multi-Purpose Waterbased Acrylic-Alkyd Interior Primer. The product data sheet says that soft plaster "should be treated with a solution of 1 pint household vinegar to 1 gallon of water. Repeat until the surface is hard, rinse with clear water and allow to dry." I wonder if that means the soft plaster will dissolve and you have to stop when you reach the hard plaster, if any. Because I don't really want that. But I think I'll test the vinegar solution now.


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## ClarenceBauer (Mar 4, 2005)

Brohoho said:


> I found MFA Plus deep penetration primer that "penetrates the plaster up to 10 mm deep" but it seems obscure so I crossed that off my list.
> 
> I found something about vinegar hardening plaster, then all I found was that it dissolves plaster which I didn't really want. Then I read that alkyd primers are good for plaster and I found one (a modified one, I guess, because of the acrylic) that cleans up with water: Multi-Purpose Waterbased Acrylic-Alkyd Interior Primer. The product data sheet says that soft plaster "should be treated with a solution of 1 pint household vinegar to 1 gallon of water. Repeat until the surface is hard, rinse with clear water and allow to dry." I wonder if that means the soft plaster will dissolve and you have to stop when you reach the hard plaster, if any. Because I don't really want that. But I think I'll test the vinegar solution now.


You need to get some good books on Plastering.
In one of the other post you stated that you did not want to follow the written instructions because it was too hard for a beginner?
You have now found where it is recommended that Vinegar & water is used to harden Plaster?
In all my years working in the Plastering trade I have never heard of it.
There are products that will harden existing Plaster & there are products that will harden new Plaster.
You should skip ALL of the info you find on "U Tube" that does not furnish an approved Standard for plaster repairs.
The ASTM Standards have many related sections.
Example:
Standard Specification for Accessories for Gypsum Wallboard and Veneer Bases.
Standard Specification for Joint Compound and Joint Tape for Finishing Gypsum .
If the Vinegar & Water does not have an ASTM Standard I would not recommend it's use.
There are proven procedures that date back to 1897 that are still valid as of this date.
You can find them in " Plastering Plain & Decorative" by William Millar Donhead Publishing LTD.
PLEASE NOTE:
ASTM standards are developed voluntarily and used voluntarily. A DIY'er does not have to follow any standards.


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## Brohoho (Jun 29, 2021)

ClarenceBauer said:


> You have now found where it is recommended that Vinegar & water is used to harden Plaster?
> In all my years working in the Plastering trade I have never heard of it.
> There are products that will harden existing Plaster & there are products that will harden new Plaster.
> You should skip ALL of the info you find on "U Tube" that does not furnish an approved Standard for plaster repairs.


It's in the product data sheet at Multi-Purpose Waterbased Acrylic-Alkyd Interior Primer (sherwin-williams.com):



> Plaster: Bare plaster must be cured and hard. Textured, soft, porous, or powdery plaster should be treated with a solution of 1 pint household vinegar to 1 gallon of water. Repeat until the surface is hard, rinse with clear water and allow to dry.


I contacted Sherwin Williams and asked:



> I'd like more information on surface preparation for soft plaster before using Multi-Purpose Water-Based Acrylic-Alkyd Primer. The plaster is 25 years old and can be scratched off with my fingernail. Your data sheet says "Textured, soft, porous, or powdery plaster should be treated with a solution of 1 pint household vinegar to 1 gallon of water. Repeat until the surface is hard, rinse with clear water and allow to dry." Should I be trying to wipe away dissolved plaster after the vinegar soaks in until I get to hard plaster, or will the vinegar solution harden the plaster while maintaining the current thickness of the plaster?


Lets see how their customer service stacks up against the nonresponsive Goldblatt and USG.


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## ClarenceBauer (Mar 4, 2005)

Brohoho said:


> It's in the product data sheet at Multi-Purpose Waterbased Acrylic-Alkyd Interior Primer (sherwin-williams.com):
> 
> 
> 
> ...


See if Sherwin-Williams will give you a reference that states Vinegar & water mixture will harden existing Plaster.
Vinegar & water will clean (etch) plaster no way will it harden Plaster.
The Gypsum in the Plaster coating chemically hardens the Lime in the Plaster coating re-carbonates.
Vinegar applied to the above will weaken the coating or break it down to a dust.
Ask the paint / primer manufacturer to quote the approval of The Gypsum Association for the use of Vinegar on any Gypsum product.
Also can you produce any info that states a paint primer can be / should be used as a bonding agent for a Gypsum product?


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## Brohoho (Jun 29, 2021)

ClarenceBauer said:


> Vinegar & water will clean (etch) plaster


Yeah, I figured. It was poorly written. I guess it would help me scrape it away.



> Also can you produce any info that states a paint primer can be / should be used as a bonding agent for a Gypsum product?


I don't recall seeing anything official that says a gypsum product can be put over primer. I've seen "sticks to all surfaces" claims for primer, and it's pretty common to mud over paint, and I've occasionally seen mention of primer under mud from random sources which encouraged me.


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## ClarenceBauer (Mar 4, 2005)

Brohoho said:


> Yeah, I figured. It was poorly written. I guess it would help me scrape it away.
> 
> 
> 
> I don't recall seeing anything official that says a gypsum product can be put over primer. I've seen "sticks to all surfaces" claims for primer, and it's pretty common to mud over paint, and I've occasionally seen mention of primer under mud from random sources which encouraged me.


You are mixing apples & Oranges.
Apples = Mud & mud is made up using mud = Attapulgite clay which is Joint Compound & it will adhere to primer/ paint mud is effected by moisture.
Oranges = Gypsum is made from rock when heated turns to a powder & mixed with Lime & water wants to return back to a rock stage. Plaster (gypsum) can withstand a lot of moisture / water, mud applied / mixed over Gypsum will separate / delaminate.
A paint primer will not allow a good bond / adhesion to a Gypsum product again moisture becomes a problem over time.
Why would you want to use a primer / bonding agent that does not become part of the substrate that it is applied to.
Take some old repairs that were done using a primer / bonding agent & if you demo it very carefully you can see the primer / bonding agent.
It will be very interesting to see how many problems come out of all the water / moisture from the hurricanes & heavy rains & flooding combined with no power for air circulating that cause joint compound & paint failure over a Gypsum system where the Plaster remains intact & hard.
You also quoted the TL&PA ,check any Lath & Plastering Association & see what they tell you about the Vinegar , Joint Compound / mud used over a plaster system also paint primer used as an adhesive.


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## Brohoho (Jun 29, 2021)

Unofficial source, but here are two posts in a row from another board that address the primer and vinegar issue:

"Sounds like water damage has change the PH of the old plaster. Like stated above spray a vinegar water solution to harden the lose areas.."

and

"If the area that you are repairing is bare plaster you should first prime the plaster or affected area with an alkyd primer before patching."


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## ClarenceBauer (Mar 4, 2005)

Brohoho said:


> Unofficial source, but here are two posts in a row from another board that address the primer and vinegar issue:
> 
> "Sounds like water damage has change the PH of the old plaster. Like stated above spray a vinegar water solution to harden the lose areas.."
> 
> ...


PLEASE NOTE: none of the above have quoted a spec. or ASTM standard.
AS per ASTM C-842-85 page 150 Para. 7.9 Bonding Compound- Specification C-631.
Para. 8.2.3.2" Use bonding compounds to bond plaster to solid bases having low or questionable suction. Apply the bonding compound in accordance with the manufacturer's printed directions. Do not use bonding compounds that are water re-emulsifiable in areas of a building where cyclic or continuous exposure to very humid or wet conditions or in which a dew point condition may occur in the plaster."
Section 09210 Gypsum Plaster ASTM C28 Para. 2.02 Item # D Plaster gypsum bonding type.
You have to select the bonding compound that meets the above requirements. 
Para. 3.02 Item E. Apply bonding agent in accordance with manufacturer's instructions.
ASTM C-843-76 Para. 7.4 Liquid Bonding Compounds - Bonding compounds may be used at the discretion of the design authority and shall conform to the requirements of Specification C-631.
Being you are working on a ceiling where the temp. above can / could be higher that the room temp. where is the dew point going to occur see above Para. 8.2.3.2 may cause delamination when the wrong product is used.


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## ClarenceBauer (Mar 4, 2005)

Brohoho said:


> Unofficial source, but here are two posts in a row from another board that address the primer and vinegar issue:
> 
> "Sounds like water damage has change the PH of the old plaster. Like stated above spray a vinegar water solution to harden the lose areas.."
> 
> ...


I did a little checking in my very old Plaster books.
Vinegar will not effect Gypsum it will not soften or harden it, the Gypsum will remain as it was when the vinegar was applied.
Vinegar will turn re - carbonated Lime into a powder.
Taken from William Millar's plaster book: quote " To harden Lime, Solutions of sulphate of Zinc, sulphate of Iron, and sulphate of copper are used for this purpose."
I also placed a leaf made from Hydrocal Plaster in straight Vinegar for 24 hrs. NO ill effects noted.
Hydrocal Plaster has a PSI of 3000 lbs. when set & 6000 PSI when dry.
So from what I can find Vinegar will only remove the Lime from the Plaster surface & will have no effect on the Gypsum that was used in the Plaster.


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## Brohoho (Jun 29, 2021)

I tested the vinegar solution (one pint to one gallon of water) on about 3" of the ceiling, about four coats, and it seems to scratch just as easily, even after drying for a couple of days. It created a small slurry when I brushed it on which I didn't wipe away. The result was bubbles and wear. I probably won't be using vinegar.


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## ClarenceBauer (Mar 4, 2005)

Brohoho said:


> I tested the vinegar solution (one pint to one gallon of water) on about 3" of the ceiling, about four coats, and it seems to scratch just as easily, even after drying for a couple of days. It created a small slurry when I brushed it on which I didn't wipe away. The result was bubbles and wear. I probably won't be using vinegar.
> 
> View attachment 664110


Good choice not to use it.


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## Brohoho (Jun 29, 2021)

Brohoho said:


> I contacted Sherwin Williams and asked:
> 
> 
> 
> ...


No response. I think if you check the "I'm a do it yourselfer" box and your question is harder than "does this come in blue" or "do you have a store in my state" then there's no chance customer service will know or research the answer. You'll be ignored. So, Sherwin Williams' labels can't be trusted, probably won't be fixed, and I'm looking for a different brand. It may be just as well that they were already closed when I got there 15 minutes before closing today.


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## Brohoho (Jun 29, 2021)

I have to admit, Sherwin Williams' in-store sales people are helpful. It's hard to get the primer I want these days but I went to two stores and the guys looked up where I could get it. They're still not perfect though. The stock they check with their computers is misleading and sometimes wrong. At the second store I went to, I was told sometimes the stock is reserved for a certain customer. The guy called the location to make sure I'd be able to pick one up if I go there the next day. And the computer said he had five gallons of the primer in his own store, which surprised him. He checked and he had none. So, tomorrow I'm going to a "commercial" Sherwin Williams that supposedly will let me buy one gallon.


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## mark sr (Jun 13, 2017)

Instead of just checking to see if a particular store had it in stock they should have called, verified and had them set that paint aside for your arrival. If they don't offer - ask them to.


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## Brohoho (Jun 29, 2021)

I finally got the primer but in addition to plaster I wanted to use it directly on glossy paint. The website says the primer assures adhesion of the topcoat to glossy paint, but the label says to sand glossy surfaces dull. So I'll either sand my old glossy mystery paint or get a different primer for it.


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## mark sr (Jun 13, 2017)

scuff sanding is always a good idea no matter what primer you use


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