From: schultz@halley.est.3m.com (John C. Schultz)
Subject: Re: Epoxy paint on concrete floors
In-reply-to: gregw@NeoSoft.com's message of Sat, 26 Dec 1992 16:40:06 GMT
Organization: 3M Company, 3M Center, Minnesota, USA
Date: Mon, 28 Dec 92 00:42:45 GMT

In article <BzvKyw.Ey8@NeoSoft.com> gregw@NeoSoft.com (Greg White) writes:

   My thoughts were to level out any rough spots in the concrete slab
                       ^^^^^^^^^
Your concrete slab should (?) be smooth enough not to need leveling. I
think that a thin coating of anything would tend to chip much more
than the couple inches of concrete used for the floor.

   and paint the floor with a durable epoxy paint decorated with
   designs and washable throw rugs.

I have used a two-part epoxy paint from Sherwin Williams with excellent
results.  You need to ask for it because it is not normally displayed.  It is
called an "Industrial Maintenance Coating, Tile-Clad II Enamel". I have
painted part of the garage floor and my shop floor with this epoxy.  I
apparently spread it quite a bit thinner than recommended because I got about
50% or so more coverage than the can recommended (185 sq ft/gallon - 9 mils
thick wet).  It seems OK however because it is still there after two MN
winters.  Probably even my garage floor does not take the beating an
industrial environment would mete out.

Sherwin Williams sells a wide variety of colors and could probably mix about
any color you had in mind - I used a battleship gray but you could go with
flourscent orange if you have a wild side (or are color blind :-)

You have to prepare concrete by etching with muriatic acid (dilute
hyrdochloric acid).  Muriatic acid is sold in hardware stores by the gallon.
The fumes given off by the etching process are toxic (chlorine).  Newly poured
concrete must not be painted for 30 (?) days to allow time for it to fully
cure.  I poured the acid direct onto the floor in a room with all the windows
open, wearing a face mask and with a good breeze blowing (it was summer).  I
swished the acid around with an old broom and old shoes and washed the room
down with lots of water.  There was not much left of the broom when I was
done.  An old mop would work OK also.  Avoid metal since the acid seems to eat
that faster.

The surface to be painted must be between 55 and 95 F. The mixed life of the
epoxy, called the pot life, is about 8 hours

The paint will not hide the inevitable cracks in the concrete slab.

As far as I know, no chemical will remove epoxy paint once is cured (maybe
acid?).  MEK (methyl ethyl ketone) can be used for cleanup before the resin
cures but not afterwards.

Drying epoxy paint also smells terrible (the carrier solvents are xylene,
mineral spirits and naptha).  You may want to schedule a week where everyone
lives someplace else so you can prepare and paint the floor.

I have no idea if you can lay tile over epoxy - you better check with a tile
store because as I mentioned, nothing is going to remove cured epoxy paint.
I would guesstimate that some ceramic adhesives will not stick to epoxy paint.
the manufacturer does not recommend epoxy for immersion service.

I would recommend that you sprinkle some fine silica or other small grit
material on the drying epoxy.  I did not and almost broke my neck the first
time I stepped on the SLICK surface when it was wet. Eventually the surface
gets abraded enough to be walkable but some fine grain silica (e.g.
sandblasting silica) would certainly help.  Perhaps you could mix the silica
with the paint and paint the mixture to get a more even application.

I applied the epoxy with a short nap roller.  I threw the roller away rather
than trying to clean it.

This particular epoxy paint takes 2 weeks to fully cure.  You can walk on it
the next day but you shouldn't drive on it or probably put heavy objects like
furniture on it for a week.  

As for epoxy's stability, I no longer wory about gas, brake cleaner, engine
degreaser, salt, oil, paint thinner, brake fluid, methanol or paint getting on
the floor in the garage or shop. Most things just wipe off.  Paint can be
disolved and wiped off.  Note however that the epoxy is no stronger than the
underlying surface and concrete will still chip.

The biggest drawback besides the preparation is the cost.  About $25 per
gallon and the minimum quantity is a gallon of hardner and a gallon of enamel.
Still pretty cheap as floor coverings go.

--
   John C. Schultz   +1 (612) 733-4047   schultz@halley.serc.3m.com
   How to include the taste of Glendronach in a multi-media system?
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