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Preparing Concrete Floor for Painting

gjrepesh

Cast Iron
Joined
Aug 30, 2002
Location
Royse City, TX
I am preparing the concrete floor in my shop for painting...epoxy. I have two issues to address. The finish on about 1/3 was not very flat or smooth in places. I rented a floor grinder and have this section much flatter and smoother. The process did remove some of the stones from the concrete so there are divots that I would like to fill. Any recommendations on what would be a good product to fill these in? I was thinking some kind of two part epoxy or maybe a product that I used on larger problems called Rapid Set Cement All. It seems to adhere to the existing concrete quite well but I don't know about small areas like the stone holes.

Also I have some surface crack in the concrete. I am thinking of using a diamond disc to open the crack up and use the Rapid Set Cement All to fill in. I don't want to go too deep...maybe and inch. Any thoughts or comments on this?

After the repair is done I plan to rent the grinder again.

I would appreciate hearing from anyone who has done this type of concrete repair and what you recommend. Thanks. Gary R.
 
Hey man: I used to work at a composites supplier for a long time dealing with this to making multi million dollar boats. My advice, stick with huntsman epoxy products. Specifically look at the cold room floor coating as they are not only non slip they fill cracks and can go on with a paint roller and self level. It's good practice to give everything your about to re-adhere to a quick wipe with acetone (not a drench) and then reapply. It's been a while but find a huntsman distributer near you. They have 2 part products in caulking guns that work a treat for filling gaps and holes in a pinch. I used to know every product by even product code, now I can't remember my own birthday. But huntsman people really know their stuff.
 
I used the epoxy I uses on the floor

i prepared the holes with a big masonry drill rumbling around in the divots even making a undercut
Then i did primer it along with the rest of the floor Then I put some filler in the epoxy like dry coarse sand or talcum[pwder for shallow divots and filled the divots
I also used that to make a big fillet at the corners of the floor and wall to make it oilproof

peter from holland
 
Peter, I also thought about using epoxy with some filler material. Glad to hear you did this. Have you noticed any problems from traffic where the divots were filled?
 
I repaired a hole in the concrete floor of the storage like that. I did not paint it, I use a 3.5 ton forklift on that floor regulary
I used talcumpowder as a filler and the colourless primerepoxy to match the color of concrete I tried to find it the other day to show it to someone Could not find it anymore


peter from holland
 
Yeah fillers for the right purpose. Talc is also a fire retardant. Micro balloons, cotton flock, and fumed silica have their place. Silica is good but makes the filler brittle without milled fibres. Serious they make cheap product to do this job once and for years to come.the two part epoxy gun is less than 20 bucks and will pull the road up around a cats eye. They stopped using it on Qld roads because it destroyed bitchu,en trying to get parts off it gripped that well
 
The use of talcum powder as a filler is not a good idea as it's hygroscopic. On boats the solution is to use glass micro balloons just for this reason.

Talcum was what I had at the moment
I also have usedtalcum to make my own spray-on filler Mix it with any leftover paint And put a lott of it in it Volumewise about 1,5 to 2 parts Talcum
Sands real smooth Only takes a while to dry

peter from Holland
 
I was thinking about using the dust from the concrete grinding to mix with the epoxy. I used a vacuum attached to the grinder to keep the dust down. It did the job. Any downside to this use?
 
And if your epoxying bare concrete there is actually a proper process of first laying down a layer of epoxy that not only seals the concrete but gives a proper substrate for the epoxy floor coat to bind on to shuddup SJ no one is listening to you suggesting they call huntsman advanced materials but everyones and expert at trial and error and can afford downtime on their shop floor.
 
The use of talcum powder as a filler is not a good idea as it's hygroscopic. On boats the solution is to use glass micro balloons just for this reason.

Talc is not hygroscopic. It has an equilibrium moisture content of 2.25% at 93% relative humidity.

You may have been thinking of maize starch, which is often used as a talc substitute and has an EMC of 18% under the same conditions.

My worry would be that is isn't very hard at all and might produce a less strong filler than, say, silica sand.

:cheers:
 
The main thing I did was epoxy the floor of the workshoparea
The cornerfillets with the silica sand filler was all original material and recipy from the supplier
The repare of the concrete was a fix from some leftovers
If it did not work there was no harm done But so far it held great And thats about 2 year now

Peter from holland
 








 
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