True Grit ?

[rockyballbuster]

OK, I've heard several different posts expain the finer details of roughening a finished epoxy coat for the next application. Each stated a different grit. I've seen 50, 60-80, and 100-120.

Which is it? Which is the TRUE GRIT?

I need to "roughen glossy surfaces" for the next coat.

(epoxy manufacturer is closed at this hour, or I'd call him).

Also any tips on doing this other than use a drywall sanding pad and ext. rod, then clean up w/alcohol?

 

[thegarageguy]

Just need to degloss it...setting a certain grit is impossible because every epoxy has a different hardness level...just knock off the shine and solvent wipe it and you'll be fine

 

[pd59]

If you are within 24 hrs. since your last coat you shouldn't have to do this, otherwise thegarageguy is right.

 

[rockyballbuster]

The Spec sheet application section states:

Avoid thick glossy areas of Amerlock Sealer. Roughen these areas prior to topcoating.

The "max" time to recoat/topcoat is 1 month. The sheet also states "roughen surface if max recoat/topcoat time is exceeded".

This looks kinda glossy to me.

[/IMG]

Looking at it closely, I did lay it WAY too thick. In spots, when looking through the surface, it appears it's 0.25 inch to the concrete. I'm hoping that's an optical illusion, because the specs call for 1.5 mils, ha ha. The cure time at 1.5 mils is 22-24 hrs, so I'm thinking a couple extra days cure won't hurt it, neither will the "roughening" up the surface?

Finally, @The Garage Guy, will cleaning it with solvent dissolve or melt this sealer. It's what I used for cleanup. I saw alcohol called out on another post.

 

[thegarageguy]

Just go to your local rental place, get a square buff sander and use a 60, 80 or 100 grit screen, which ever deglosses it better.

Vac it all up and wipe it with denatured alcohol or acetone. Don't pour the solvent on the floor, just dampen a lint free rag enough to pick up the fine dust.

Finally, apply whatever sealer that you desire

 

[rockyballbuster]

Talked to the PPG rep. He said scratch it up and go for it, drying time's not an issue even though it's thick.

Garageguy, thanks for all your help. That square buff sander sounds like the way to go... more and more as I sand it by hand, whew !! I couldn't find one to rent in my little town. Thank God the temps aren't going to get too high today...

More pics to come after the next coat!

 

[thegarageguy]

Your welcome...looking good so far.....looking forward to the finished pics

 

[rockyballbuster]

The saga continues. Today, I learned the difference between "theoretical coverage rate" and "actual". Apparently, so did the Pittsburgh paint sales rep. Theoretically, the paint should cover 468 s.f./gal (at 5 mil wet thickness). With our project at 820 s.f. you'd think that 3 gals should do it, eh? No such luck, and we didn't even put it down at 5 mils, more like just enough to cover the sealer coat without showing through (1 mil??). I'm told theoretical is assuming you're painting a suface of glass, so any discontinuities in the actual surface reduce the theoretical coverage accordingly, but come on, actual comes out to less than 60 percent of theoretical. PPG's sending another gallon up from CA arriving tomorrow. Let's hope it color matches (I've seen that thread too!).

At this point, all I can do is laugh... and drink!

 

[AlphaGarage]

The saga continues. Today, I learned the difference between "theoretical coverage rate" and "actual". Apparently, so did the Pittsburgh paint sales rep. Theoretically, the paint should cover 468 s.f./gal (at 5 mil wet thickness). With our project at 820 s.f. you'd think that 3 gals should do it, eh? No such luck, and we didn't even put it down at 5 mils, more like just enough to cover the sealer coat without showing through (1 mil??). I'm told theoretical is assuming you're painting a suface of glass, so any discontinuities in the actual surface reduce the theoretical coverage accordingly, but come on, actual comes out to less than 60 percent of theoretical. PPG's sending another gallon up from CA arriving tomorrow. Let's hope it color matches (I've seen that thread too!).

At this point, all I can do is laugh... and drink!

As you're enjoying the drink - and cooking up some meth - let's do a bit of high school math....

One gallon of ANY liquid will cover 1,604 square feet (ft2) to a depth of 1 mil. That means, if you spread ONE gallon of water on a surface at 1 mil thick, you would cover 1,604 ft2. If you spread one gallon of paint at one mil thick on the same surface you will cover... 1,604 ft2. How many square feet will a gallon of milk, root beer, or even crocodile tears cover at 1 mil thickness? That’s right... 1,604 square feet!

So, if Mr. Pittsburgh paint sales rep. tells you that they recommend their coating be applied at 5 mils wet, what's the most area that one gallon can cover at that depth? 1,604/5= 320.8. That would be 320.8 ft2 and not a square inch more. Factor in about 10% waste and the actual square feet it could coat is more like 288 ft2.

Again, going with their 5 mil min wet depth, with 820 ft2 you should use...
820*5 = 4,100 + 10% (waste) = 4,510 / 1604 = 2.81. Must have had some thirsty concrete!

BTW - Love the name & avatar! Best show on TV.

 

[rockyballbuster]

Thanks for piping in and 'splainin' the finer points of paint coverage based on logic. I see the proof you point out. Important to mention, "theoretical coverage" is also based on the % solids. The spec sheet lays it out for the dry mil thickness. If 100% solids, at 1 mil, you will get 1604 s.f/gal. If 90, you get (0.9 * 1604) s.f./gal.

One thing that I will dispute is the 10% loss rate. It may be a good thumbrule, but should account for few things which may vary by project. The loss should account for uneven surfaces, transfer losses, equipment and tooling losses, and resin-smoking gremlin consumption (take the latter into consideration only if you're using my product, heh heh). Stem walls are a quagmired moonscape, and in this case sucked up a good half gallon on their own. The other major losses are transfers with spills here and there, and to a larger extent, the rollers and brushes and pails/pans. Rollers are veritable sponges, and brushes magically soak up craploads themselves. Sooooo....

So, the % loss rate should be taking into consideration:

1. How much stem wall/rough surface you have
2. The application method (rollers/brushes or spray or squeegie)
3. How inept your workers are and likely to spill the product
4. If anyone working the project copped any blue the night before

What was my loss rate? I am updating my s.f. to 830 vs. 820, btw

(4150/1604)=2.58 (theoretically the gals I needed to cover 830 s.f. at 5 mils)

I used 3.3 gallons.

(2.58/3.3) - 1 = the efficiency which comes out to a 78% (22% loss)

++++++++++++++++++

OK! Now that the paint coverage dilemma is solved (theoretically), I'll give everyone an update on the project. The product arrived as promised today. I put it down, and was pleased to see that it's a perfect color match to the other section -- for once on this project, Rocky's balls were not busted.

Tomorrow AM, we put down the final clear coat. Theoretical coverage at 2 mils, 642 ft sq/gal. I just did the math and it works out -

(1604/2) X 0.80 (percent solids) = 641.6

I have 3 gallons of this. I'll be more sparing on the stem walls. I'm confident, barring an onslaught of more resin-smoking gremlins, we should be fine.

 

[thegarageguy]

Hey Alpha, Do you where a protractor and pens on your chest pocket? ;p You heard the term, "It looks good on paper".

I couldn't agree with rockyballbuster more. Yes, theoretically you are correct....but when you are working on uneven and sometimes very pourus surfaces, the theory is thrown out the window.

As a contractor, we always show up with more than we might need, just in case.

 

[rockyballbuster]

Here it is, clear coat this morning, tried to avoid huffing fumes - dang!

All that's left is the rubber wall border, and filling the exp. joints with foam backer and self leveling Sonoguard SL-1. I'm hoping this floor lasts a long time...

 

[pd59]

Just wanted to say that is a great looking floor you have there. Nice job!

 

[rockyballbuster]

Thanks PD59, GarageGuy, AlphaGarage and the others that helped me get to this phase. Mr. Pollo can't wait to finish this project, and have my lab, er... I mean "garage" back. BTW, did you check out the epoxy floor in the BB lab? After starting this project, I took note, and was wondering what system they used, ha ha.