Black Epoxy Coat/Grinder Prep for now...

[rpm911]

Hello everyone,

Long time listener, first time caller... I am in the process of prepping for my black Epoxy-Coat floor. I have an acrylic sealer on, I am grinding that off. Original plan was to shotblast...400/day, on to diamond grinder walk behind... 300/day. However, a local S/W store has one they rent for 125/day, no cup fees!!!

The machine, however, has "disappeared" the last renter has not called them back. They do have a broken vacuum so they will rent to me for 62.50... if it ever comes back!

Anywho... I have started handgrinding the edges with a 4 1/2 in that I got, and I may go get a 7" and start working the whole floor. The biggest problem so far is the gumming of the cup. At present I am using a wirebrush to help clear it. It is very persistent... I don't know how long this 4 1/2 will actually last either, I got it at harbor freight for around 30 bucks... (use their 20% off coupon and a free stuff with purchase coupon too

So far I have spent 3 1/2 hours and have completed the perimeter of a 10.5 x11 ft section. (I have about 440 sq ft to do). If this keeps up I may consider soy gel, but I'm told it's going to be about $300.00 by that company for 5 gallons plus shipping.

Any thoughts or tips about the gumming? I'm more worried about what may happen if I have the same problem with the walk behind. Anyone used soy gel... Is it REALLY as good as they say???

Anyways... I've loved reading the posts here for about 2 years now... I'm really glad to be getting on with this project. Wife says I have to be done by the 20th.. I start back school full time for the next 2 years, so money has just become VERY tight... I didn't know that would happen when I embarked on the project! Lost my job... So again... money saving tips are GREATLY appreciated!

Thanks!

The beginning

Threshold

Patching where UV damage occurred... should have ground this first? I'll fix it...

30-40 mins of progress...

About 2:15 in.... f#*@... this is taking a long time... back hurts... 98F with 90 humidity... Flipping Ohio River Valley... Where is that walk behind?????

T+ 2:50 roughly....

The wheel on the grinder keeps gumming up. Gumming up. Gumming up.

http://i105.photobucket.com/albums/m211/rpm911/Garage%20Floor/IMG_0418.jpg[/IMG
The light areas are where it has gummed, and collected dust... wire brush to the full speed head helps a little.

[IMG]http://i105.photobucket.com/albums/m211/rpm911/Garage%20Floor/IMG_0419.jpg
Section 1 perimeter... done.... I'll have to pay attention and make sure I fill gouges... as I now have a few.

 

[fullthrottle24]

I am like you, long time looker, now it's time to share my experience. I just finished my 150 sq ft utility room with epoxy coat. I rented a 7" blastec grinder and blastec vacuum from local Home Depot. Used a medium life diamond cup wheel($49 dollars to buy at Depot.) The vacuum is key. It has a plunger that shakes dust off inside the vac, so it doesn't clog like shop vacs. The grinder made short work of previous painted concrete without gumming. My biggest mistake was a couple of times the hose came off the dust shroud sending dust everywhere. In my haste, I must have tipped the wheel on edge slightly, causing uneven grind marks. The epoxy coat will show everything, so just take your time with the grinder. It's hard work, no doubt about it.

 

[LegacyIndustrial]

Yes the soy gel is great for an acrylic sealer.

 

[rpm911]

Thanks,

The Home Depot didn't have it... however, SW called back, the machine came in... I went and picked it up. I was grinding from 4:45 to 9:30. I think I'm making less progress with this freaking thing. Although, it is much quieter and more comfortable than being on the floor hand grinding, also about 100 times cleaner with my cheap little shop vac and a drywall bag.

So, now considering a wet grind...

 

[Edger]

Thanks,

The Home Depot didn't have it... however, SW called back, the machine came in... I went and picked it up. I was grinding from 4:45 to 9:30. I think I'm making less progress with this freaking thing. Although, it is much quieter and more comfortable than being on the floor hand grinding, also about 100 times cleaner with my cheap little shop vac and a drywall bag.

So, now considering a wet grind...

Hi,

Maybe a cost-saving tip. Go to a hardware store and pickup a small bottle of muriatic acid, also known as hydrochloric acid or spirits of salts. Use a plastic cup or bowl and mix it into various amounts of water. Always pour the acid into the water, not the other way round. You want to finish with four different dilutions and one of these may remove the coating. Try 2:1, 3:1, 5:1, 7:1. The "one" is the acid. Get a paint brush and paint out each dilution in a long strip to thoroughly wet the floor area leaving a gap between each dilution. Then use a water jet power washer, minimum 2,000 psi and wash off half the test strips after 5 mins, then wash off the remaining half after 15 mins.

That means you have long test strips so you can blast away the furthest half of each length, then the nearest half.

Very often the acrylic sealer will be released by one of those dilutions, but not so with epoxy. If you do not want to hire a water blaster for the test use a garden hose, then scrub all of it with a stiff bristle brush, you should still see if one of them removes the coating.

This low cost test shows you what dilution works and how long to leave it on. If it removes the coating it should be easier and lower cost than grinding. The problem with grinding is that acrylics (unlike epoxies) are soft and melt with heat so they clog up the diamond wheel and are a real pain to remove.

Also you need a diamond wheel that has a soft bond and big diamonds which will do the job much faster, however these are not found in hire companies who like hard bond and finer diamonds because they take longer to wear out. To explain how to tell if your concrete is too hard for the wheel go to http://www.situp.com.au/Grinding Hard Concrete.html because you can tell by looking at the diamond segments on your wheels.

 

[rpm911]

Edger:

Thanks for the good advice, I unfortunately ended up grinding for 40 hours total... yeah. I still have stubborn spots. I tried a 4:1 muriatic acid wash today, with virtually no change in the stubborn areas. I am going to try it as a 2:1. Half of my floor is ok, the other half... I had to give up to take the machine back. The side that didn't come up as well was passed over 5 very slow passes, waffling back...

Hope the 2nd pass with acid works better!

 

[Edger]

Edger:

Thanks for the good advice, I unfortunately ended up grinding for 40 hours total... yeah. I still have stubborn spots. I tried a 4:1 muriatic acid wash today, with virtually no change in the stubborn areas. I am going to try it as a 2:1. Half of my floor is ok, the other half... I had to give up to take the machine back. The side that didn't come up as well was passed over 5 very slow passes, waffling back...

Hope the 2nd pass with acid works better!

Believe me, happens to professionals too and they have a greater range of tools. You might try a Zec disc on an angle grinder which is a very rough, flexible disc to remove the bits left. It does not bite into the concrete as much as a diamond grinder although it tears into a coating but will still be dusty and make a mess. Sounds like your concrete is hard which prevents the diamonds from opening up and cutting. Good for your floor, no good for diamond grinding without soft bond diamond segments. Good luck.

 

[srode]

I am going to try it as a 2:1. Hope the 2nd pass with acid works better!

I had to use 1:1 or 50% acid water mix on mine to get a good etch, and some spots needed to be hit twice.

 

[Hmrhead]

Not to be a downer about the Black floor, but have you seen/been on one before? From your pictures it looks like this is for a daily use garage. A Black floor is like a black car, every smudge shows up. My neighbor across the street has one, looked awesome when he put it down. First time he walked on it after going to get the newpaper at the end of the drive he left dust prints across the floor. He was so determined to enjoy his floor he must have damp mopped it a 100 times. He now has carpet runners to walk on and purchased RaceDeck to park the cars on. If I had a show worthy car and a space to park/display it I would put down a black floor in heart beat, it really looks great. After seeing every foot print, bike tire track, wheel track on it. It made me rethink my color choice when it comes time to do my floor. BTW he used Epoxy Coat and thinks its great, he just wants a different color now. No offense, just my 2 pennies

 

[rpm911]

Srode: Where you going through an acrylic sealant?