I will be etching with muriatic acid dilution my new concrete garage
floor prior to epoxy application.
How long after etching can I wait until I epoxy the floor. Assuming I
keep it clean.Does etching have a life expectancy after which I will
have to etch again. The problme I have is that it mat take weeks before
I have the time to epoxy after etching. thanks for your advice

On Oct 15, 9:30*pm, jb wrote:
I will be etching with muriatic acid dilution my new concrete garage
floor prior to epoxy application.
How long after etching can I wait until I epoxy the floor. Assuming I
keep it clean.Does etching have a life expectancy after which I will
have to etch again. The problme I have is that it mat take weeks before
I have the time to epoxy after etching. thanks for your advice

I fail to understand the compulsion for a epoxy or painted garage
floor.

garage floors are supposed to be dirty with grease and oil stains, not
a fancy finished surface that will sooner or later demand
recoating....

given all this first the garage floor must be cured, say 6 months,
during this time you shouldnt use the garage for anything lest it gets
dirty.......

then etch it and epoxy within a few days check the epoxy manufacturers
recomendations..

JB:

If the manufacturer of the epoxy recommends you etch your concrete first, then I'd do it. Otherwise, a poured concrete slab is a rough and porous material that any coating should stick well too without having to make that surface rougher still.

But, to answer your question, once you etch that concrete, you make it rougher, and it stays rougher until you do something else (like polish it) to make it smoother. It may get dirtier if you leave it for a while before painting it with epoxy, but it's not gonna get smoother on it's own.

Fresh concrete is highly alkaline, and so oil based paints (and inexpensive latex paints) won't last on fresh concrete. You can use a concrete primer which are made specifically for painting over fresh concrete, but these are essentially latex primers, and it's never a good idea to put a hard strong coating (like epoxy) over a softer weaker one (like latex primer) cuz then the harder coating will be prone to "chipping" because of the weaker coating under it breaking when it receives an impact or can't resist some force applied to it.

Typically it takes at least a year for the alkalinity in fresh concrete to subside, so the general rule is not to paint concrete for the first two years of it's life. However, I don't know how resistant epoxy coatings are to alkalinity, so that rule might not apply to epoxies.

What you SHOULD do is buy a small roll of vapour barrier and tape pieces of that plastic together to cover your garage floor. Tape the perimeter of the plastic down, and slip a hygrometer (measures relative humidity) dial side up under the plastic before you completely finish taping down the perimeter. Lee Valley and most hobby shops will sell hygrometers.

Watch that hygrometer needle. If the concrete is more than a few weeks old then any water evaporation from it won't be the mixing water any more. It'll be moisture migrating up through the concrete slab from the ground (or crushed limestone base) below. And, if moisture is coming up through the slab, I'd be reluctant to paint that floor with epoxy unless and until I measured how much moisture was evaporating and whether that fell within the guidelines of the company that makes the epoxy floor paint you want to use. That's because if you have too much moisture evaporating from the concrete it can build up sufficient pressure to push any coating off the concrete, even epoxy. In that case you'll find that your epoxy floor is peeling in places.

By covering the floor with plastic, you trap any escaping moisture, and it becomes a steadily increasing relative humidity under the plastic. If you see the hygrometer needle rising, then expect to see condensation first forming on the underside of the plastic over the area(s) where the moisture is evaporating from.

When I replaced the Olefin carpets in the living rooms of my apartment block, I'd put the old carpets in one of my sister's garages. That gave them a flooring that wasn't slippery when it was wet, absorbed oil and grease to keep the underlying concrete cleaner, was easier on the knees to kneel on and warmer to lay on when doing any repairs to their cars. And of course, it cost them nothing and those old carpets weren't any good for anything else.

If you find that there's moisture coming up through your concrete slab, phone around to the carpet retailers in your area and ask to speak to the installation managers. Ask the installation managers who sells flooring installation supplies in your area. Those installation supply stores should carry "calcium chloride test kits" (IIRC) which are used to measure the amount of moisture coming up through the concrete floor. Every flooring manufacturer will have guidelines as to how much moisture his flooring will allow to evaporate through it. You might want to get one of those kits and see if the moisture evaporation rate from your slab is within the guidelines of the company that makes the epoxy floor paint. Set up your test kit in any areas where you see condensation forming on the underside of the plastic over your garage floor.

Park your car(s) outside while you're testing the slab for moisture evaporation.

Or, at least, that's the way I'd proceed with this.

On 10/15/2012 9:30 PM, jb wrote:
I will be etching with muriatic acid dilution my new concrete garage
floor prior to epoxy application.
How long after etching can I wait until I epoxy the floor. Assuming I
keep it clean.Does etching have a life expectancy after which I will
have to etch again. The problme I have is that it mat take weeks before
I have the time to epoxy after etching. thanks for your advice

I etched my basement floor over 35 years ago before I painted it and
have done nothing since except minor touch-ups. I painted the next day
after etching but that was with water based paint and I don't know if
surface should be drier for epoxy.

One thing I recall was using a sponge mop for the etching and it
disintegrated as it was probably polyurethane.

On Mon, 15 Oct 2012 21:30:01 -0400, jb wrote:

I will be etching with muriatic acid dilution my new concrete garage
floor prior to epoxy application.

When etching is do, neutralize to acid with soda, Rinse well after
that.

How long after etching can I wait until I epoxy the floor.

The epoxy can label will have instruction on when to apply the epoxy
after etching.

Assuming I
keep it clean.Does etching have a life expectancy after which I will
have to etch again. The problme I have is that it mat take weeks before
I have the time to epoxy after etching. thanks for your advice

On Mon, 15 Oct 2012 18:59:40 -0700 (PDT), bob haller
wrote:

I fail to understand the compulsion for a epoxy or painted garage
floor.


See the hanger floor. I've been inside and it is spotless. Been in
several hangers working on an air force base.

http://garypalamara.com/images/Gallery_Home/05_Thunderbirds/w4Thunderbird-1_0636_HANGER.jpg

garage floors are supposed to be dirty with grease and oil stains, not
a fancy finished surface that will sooner or later demand
recoating....


Dirty garage floors are dangerous. Look at any professional shop and
you'll see clean floors - epoxy.

"Oren" wrote in message ...
On Mon, 15 Oct 2012 18:59:40 -0700 (PDT), bob haller
wrote:

I fail to understand the compulsion for a epoxy or painted garage
floor.


See the hanger floor. I've been inside and it is spotless. Been in
several hangers working on an air force base.

http://garypalamara.com/images/Gallery_Home/05_Thunderbirds/w4Thunderbird-1_0636_HANGER.jpg

garage floors are supposed to be dirty with grease and oil stains, not
a fancy finished surface that will sooner or later demand
recoating....


Dirty garage floors are dangerous. Look at any professional shop and
you'll see clean floors - epoxy.

I think what you looking at is polyurethane which may be clear or with die

On Oct 16, 4:08*pm, Oren wrote:
On Mon, 15 Oct 2012 18:59:40 -0700 (PDT), bob haller
wrote:

I fail to understand the compulsion for a epoxy or painted garage
floor.

See the hanger floor. I've been inside and it is spotless. Been in
several hangers working on an air force base.

http://garypalamara.com/images/Gallery_Home/05_Thunderbirds/w4Thunder...

garage floors are supposed to be dirty with grease and oil stains, not
a fancy finished surface that will sooner or later *demand
recoating....

Dirty garage floors are dangerous. Look at any professional shop and
you'll see clean floors - epoxy.

airplanes are much more precision than the average vehicle which will
tend to leak fluids like oil....

besides air force bases are paid for by the public so they can spend a
gazillion bucks on them.

while no one wants a slip or fall hazard garage floor, they dont have
to be perfect.

and certain leaking fluids on epoxy is likely more slippery than on
concrete