# Dirty deck?



## BoondockPaints (Nov 14, 2018)

I applied Challenger degreaser/_K_rudcutter (slightly diluted) with a back pack sprayer, and then powerwashed with hot water. I really got after it with the water (3000psi). I knew it wasn't coming 100% clean while I was washing it, but I figured this stuff wasn't coming off. Well, I got up on the lift today to clean an area I wasn't able to wash, and noticed that there is some extremely minor residue/film in some areas. I tried wiping it down with some no-rinse TSP and it does come off with enough elbow grease, but not enough to feel like I should be worried about it.
Any thoughts on this? I really don't want to powerwash it again, and I damn sure don't want to scrub it by hand. Should I do a test with some dryfall or should I just go for it? It's otherwise very clean. You could eat up here.
View attachment 113321


----------



## Holland (Feb 18, 2011)

Did you try hitting it with a mild bleach water? It looks like it might be a mildew.


----------



## BoondockPaints (Nov 14, 2018)

I have not done that. I've painted in this building before, and automotive grease was always the concern. So I just followed suit in this part of the building.


----------



## BoondockPaints (Nov 14, 2018)

Holland said:


> Did you try hitting it with a mild bleach water? It looks like it might be a mildew.


I think maybe I diluted the Challenger too much and by the time I made it back to rinse it had dried out. I was looking for where mildew might have originated and realized that about a quarter of the ceiling looks OK, and that's right about where I ran out of Challenger and switched products. So those spots might be concentrated spots of grease/grime. I'm going to grab some bleach and some more Krudcutter in the morning.


----------



## Holland (Feb 18, 2011)

If its mildew, you can wipe a small amount of bleach on your test area, and the black will smear off very easily.


----------



## jacob33 (Jun 2, 2009)

Looks to me like the cleaner took some finish with it and those circle areas that look dirty are actually spots the paint was removed as the cleaner dripped off.


----------



## jacob33 (Jun 2, 2009)

Could be mildew/mold to as others have said bleach should clean it if it is.


----------



## BoondockPaints (Nov 14, 2018)

jacob33 said:


> Looks to me like the cleaner took some finish with it and those circle areas that look dirty are actually spots the paint was removed as the cleaner dripped off.


It almost seems like that when I try to clean it, as many of the spots will not come off. Like they're imbedded almost. However, I am able to get some of them off if I try hard enough. The problem is that whatever is on there releases enough contaminant with each wipe down that it dries to a very fine dust/film. I started cleaning it by hand but I'll be there until spring. I busted out a rotary scrubber on a drill and it's still giving me hell, even with the TSP.


----------



## jacob33 (Jun 2, 2009)

I would give it one more wash with bleach and than prime and paint it. Sometimes stains do not come off.


----------



## BoondockPaints (Nov 14, 2018)

I've never primed before dryfall. What do you recommend?


----------



## BoondockPaints (Nov 14, 2018)

Bleach is taking it off but still having to wipe/scrub a little. I put some 50/50 on and let it sit for 10 minutes. It does come off but still needs mechanically wiped with minor elbow grease. Tried straight Krudcutter and got the same result.

I really didn't want to clean this whole thing by hand, but I don't know what my options are other than a stringer degreaser, or maybe hand tool an oil primer?

Now that I think of it, I was told last time I was here that there was a fire in this building about 20 years ago. I'm wondering if that's what this stuff is.


----------



## Redux (Oct 27, 2018)

What you might be seeing is saponified oil-alkyd resin paint being that the active ingredient in Challenger degreaser is potassium hydroxide. I would try a 2.5% solution of distilled white vinegar. It could also be mineral deposits from hard water used to pressure wash. The vinegar would remove that as well. 

I would avoid using chlorine bleach because the residual chloride salts need to be thoroughly rinsed and removed, otherwise they can corrode steel.


----------



## finishesbykevyn (Apr 14, 2010)

To me it just looks like dirt residue from where the water was dripping off the ceiling. Probably needs a second round of cleaning, unfortunately.


----------



## BoondockPaints (Nov 14, 2018)

finishesbykevyn said:


> To me it just looks like dirt residue from where the water was dripping off the ceiling. Probably needs a second round of cleaning, unfortunately.


That's what I thought, but about two bays in and it's giving me hell. It comes off, sorta, but it's also in the paint, if that makes sense. Some of it will wipe right off, but about half of it is part of the paint now.


----------



## finishesbykevyn (Apr 14, 2010)

BoondockPaints said:


> That's what I thought, but about two bays in and it's giving me hell. It comes off, sorta, but it's also in the paint, if that makes sense. Some of it will wipe right off, but about half of it is part of the paint now.


Well, A little dirt stain never hurt anybody. Did it? I'd just paint it. You may never get it clean. Regular latex paints are designed to withstand a bit of dirt..


----------



## BoondockPaints (Nov 14, 2018)

finishesbykevyn said:


> Well, A little dirt stain never hurt anybody. Did it? I'd just paint it. You may never get it clean. Regular latex paints are designed to withstand a bit of dirt..


I was able to get it clean, but it's on there enough that I think it will paint just fine. Whatever it is, it's bonded to the substrate very well. I hate to not have the peace of mind, but I also don't want to clean it for nothing.

(Left side cleaned by hand, right side degreased and pressure washed.)


----------



## finishesbykevyn (Apr 14, 2010)

BoondockPaints said:


> I was able to get it clean, but it's on there enough that I think it will paint just fine. Whatever it is, it's bonded to the substrate very well. I hate to not have the peace of mind, but I also don't want to clean it for nothing.
> 
> (Left side cleaned by hand, right side degreased and pressure washed.)
> View attachment 113330


Well I have to say, the left side looks waaay better. May a stiff bristle brush on a long pole? How high is this ceiling. ?


----------



## NACE (May 16, 2008)

Just a thought: How hard is the water you used?


----------



## BoondockPaints (Nov 14, 2018)

finishesbykevyn said:


> Well I have to say, the left side looks waaay better. May a stiff bristle brush on a long pole? How high is this ceiling. ?


It took some doing and in some cases took it down to metal. I was using a big sponge and a green scratch pad. I have a bristle brush I used first but immediately stopped because it won't even begin to take it off. Like I said, this stuff is bonded. There was supposedly a fire somewhere in the building and I'm wondering if the heat baked the soot into the paint? If that's even possible?

Ceiling is 18ft I believe.


----------



## BoondockPaints (Nov 14, 2018)

NACE said:


> Just a thought: How hard is the water you used?


It's city water. It's softened to "120 parts per million (ppm), or approximately 7 grains per gallon."


----------



## Redux (Oct 27, 2018)

The potassium hydroxide in the Challenger degreaser is essentially the active ingredient you’d find in a caustic paint remover (aka caustic potash)…both contain similar concentrations/pH. Even if it were diluted, it could still saponify/eat into the old paint if it were an oil-alkyd, especially if left beading on a overhead surface and not rinsed before it dried.


----------



## BoondockPaints (Nov 14, 2018)

Redux said:


> The potassium hydroxide in the Challenger degreaser is essentially the active ingredient you’d find in a caustic paint remover (aka caustic potash)…both contain similar concentrations/pH. Even if it were diluted, it could still saponify/eat into the old paint if it were an oil-alkyd, especially if left beading on a overhead surface and not rinsed before it dried.


I tried straight vinegar to no avail.


----------



## Mike2coat (Nov 12, 2013)

Its clean enough, paint that s and get paid...


----------



## BoondockPaints (Nov 14, 2018)

That's a wrap on the lid.


----------



## finishesbykevyn (Apr 14, 2010)

BoondockPaints said:


> That's a wrap on the lid.
> View attachment 113337


Did you end up cleaning the whole thing again? Or just go for it. Which product did you end up using?


----------



## BoondockPaints (Nov 14, 2018)

finishesbykevyn said:


> Did you end up cleaning the whole thing again? Or just go for it. Which product did you end up using?


I re-cleaned 75%. Basically anywhere that looked dirty enough to give me cause for concern. Ended up in a time crunch and had to go with SW Dryfall. Primed the walls with oil and the rollup doors with Kem-Bond. Top coated with precat epoxy.


----------

