Sheetrock "Green Top"

wnybassman

We have been using this compound forever, and in conjunction with a Porter Cable sander for the last 12-14 years.

About a year ago we came across a job where the sander put more of a "polish" on the compound during the sanding. It would smoothen it, but looking across it in the light it would have a shine and not the normal dull finish. You could also see the layers of the compound much more than I can ever recall, like each layer had a slightly different color. You could also feel a slight level difference at these layering lines.

We really have changed nothing. Still use 120 grit and still put the compound as we also have. Still using the same sanding pads we always have also.

The problem is, every job since then has been the same, even very small jobs.

I used to get a whole house out of a single sanding pad, now I have to change 3 times or else the "polishing" gets very bad.

Has anyone else experienced anything like this? Has the composition of the compound changed?

Kiwiman

Slightly different topic, but my last order of sheetrock total "black top" has changed to a rich yellow/cream colour, I presumed it was just more dye added but it's a lot harder finish and harder to sand, my last house I used twice as many sanding disc's and took longer, P!sses me right off, if they are going to change our product they can at least tell us, or market it as a different product for us to try. I liked the old stuff thats why I buy it...Not any more, if I wanted to buy cr*p I would buy it but now I'll be looking for something that suits me better.

wnybassman

Maybe they have done a little something different across the board in all their compounds? Sounds fishy.

The green top now reminds me of a LaFarge compound we used years ago called Classic Gold (I think). We finished an entire two story house with this stuff and the Porter Cable would not touch it. 10 minutes with a new pad and it was shot. Hand sanding would cut the compound pretty good so we hand sanded the whole house.

Same thing with the Sheetrock stuff now. A hand sponge sanding block sands it very easily, but the machine does not. On a small project we are on now we took one step back and tried the "purple top", a mid weight compound. That got glossy while sanding as well.

I suppose it could be something other than the compound, but we are doing nothing different.

Kiwiman

Maybe your sanding pad has changed if it sands fine with the sponge block. The main reason I don't use the purple top is it's too white and is harder to find imperfections (until the paints on).
Another new problem with the "black top" is it doesn't blend well where you cross a horizontal with an already dry vertical which the old formula was good for, and it's hard to blend with the board when sanding, I'm still p!ssed about it...I want the old stuff back The only good thing was it was hard to over sand it. With any luck it might have just been a bad batch and sheetrock have said - oh! just send it down to that little sh!thole next to Australia...no one will know!

A+ Texture LLC

I use USG's AP (Green) for texture when using my hopper. I usually buy from home depot. Once bought from Lowes and one time from a Do it BEST and I swear it was topping compound. Whenever I know I'm gonna shoot texture I make sure I get that box from HD. I wonder if they have different prices or cut deals to give specific stores a bad batch for less money.

Tim0282

USG adds WAY too much air to their mud. You are buying a lot of air to make the 4.5 gallons. I don't like their Plus 3 at all. And the green AP shrinks too much. And is brittle when dry. Not good. Have you noticed it flaking off when you leave a chunk? It sticks OK, just brittle when thicker.

wnybassman

That is quite possible. We have always used the PC sanding pads, mainly 120 grit. Maybe they changed.

One other thing is shortly before we noticed this happening, our old PC vac finally gave out after 12 years of service, so we replaced with another PC vac. It sucks very well. We just can't figure out why this would make a difference in how it sands.

We are keeping our minds open to every possibility.

Whitey97

They change the mud constantly trying to save a buck here and there. We've all experienced bad mud. I know, we've talked about it in a few threads. That's probably your issue. Just a bad lot of mud. Though I only use ap for 1st coats, I haven't had any issues with mine in a while.

I remember when I got a horrible pallet of +3 in 04, there was grey mold in every box. Haven't bought a box since.

Kiwiman

Was talking to my supplier today, according to Usg the only thing that has changed is the dye, I've used enough of it to know it is a lot harder finish now, don't get me wrong it's still good mud but it doesn't suit me is all.

A+ Texture LLC

Hmmm... the sheetrock guy is strangely quiet. I wonder if he just shows up when theres some marketing that needs to be done?

Whitey97

*sheetrock guy's head pokes out of closet*

wnybassman

It's getting downright annoying now. Sanded out a small job today and it took twice as long as it should have. 2k feet of board and I went through a 120 grit pad and TWO 100 grit pads. I haven't used a 100 grit in ages, and it used to take an hour or so to "break it in" where I felt comfortable I wasn't scratching at all. Put one on today and it felt like it was shot in a 1/2 hour, and went straight to polishing the compound. Hell of a shine when looking into the light. And it wasn't cutting the high spots, just smoothening out and polishing the slight rolls.

I was so frustrated I called USG on the way home. Of course I got the answer I expected, no changes to the compound.

Could be the wand or vacuum I suppose. But it just doesn't make sense that either or those two devices could cause a problem of this nature.

Pads? It seems everyone would be bitching about it.

We'll figure it out eventually.

Thanks for letting me vent

Whitey97

where are you from? you should put that in your profile.

I would be willing to send you one of my pads for the sander. Hell, I'll send you a "broke in" one just to eliminate that variable. If it sounds like something worth it, gimmie a shout.

wnybassman

I've already been looking at All-Wall for different pads. May order some just because. Also, we have already ordered the Sheetrock VLS mud for the next project. We'll see how that goes. On top of all that, the day we sand the next project we will have a friend of ours sander/vac to see if that makes a difference.

Thanks for the offer though (and I changed my profile too)

Whitey97

Well, as you know, feel free to ask anything. I will usually always give my opinion! ha

wnybassman

OK, we have tried three separate compounds now. Albeit all USG, but three different. Green, purple and brown top all acting the same. Still getting the same shiny surface when finished sanding.

I think perhaps I can strike the compound off the list of problem causers.

Sanding disc might be the next to experiment with.

The problem did roughly start about the same time (take or give a couple jobs) we replaced the PC vacuum. Hard to understand how that might cause the problem though.

Oh well, onward.

Stormy_Ny

Hey are on Ice Shanty also ?

wnybassman

LOL, I was wondering if that was you too

kgphoto

Replaced the vacuum? Perhaps it is spinning at a different RPM? To fast so it burnishes or burns the mud. Hand sanding will be slower speed.

Maybe the moisture or temperature change is affecting your mud's drying time, so it isn't dry enough. Try waiting one or two days more before sanding. Put a blob on the wall at home so you don't hold up a job.

Just a couple ideas. I don't use that sander at all.

wnybassman

The wand of the system controls the speed of the disc, and I normally sand on settings 3 through 5. I've tried all the ranges and speed doesn't seem to be the issue.

The problem has persisted from early spring this past year, all the way through the summer and now into the colder winter months. We've gone through the extremes of all seasons. No difference.

We've also sanded very soon after the last coat (basically as soon as it's dry) and have waited up to 5 days. Again, the same results.

It really seems to b the rotary action. Hand sanding is no problem, but as soon as that sanding disc starts spinning the compound glosses up.