Concrete Patching Question

[cbucner]

You will have to enlarge the crack with a diamond blade grinder and use hydraulic cement .This stuff will cure even if it's under water.
That's my 2 cents

[rtate]

Thanks for the reply...
The area is not a Crack but a circular area about 12 inches in diameter.
The area is rougher that the rest of the pool but has a maximum depth of about 1/8 inch.
My concern is that there is not enough area for the hydraulic cement to get a good "bite" on the surface and will not be able to cure because it is to thin to hold back the weeping water...
If I were to chip the area out with a chisel, how deep do I need to make the area to ensure a good bond??
Can I feather out the edges??

[waste]

Welcome, both of you, to the forum!

As cbucner sagely suggested, hydrolic cement is the way to deal with this.

rtate, you are correct in thinking that the patch needs to be 'locked in' to fully seal. I'd use the chisel (who am I kidding, I'd use the hammer drill off the van ) to create a locking 'wedge' for the hydrolic cement. The cement itself is good for patching, and works, but you want to have it stay in place

If you need more info on this, please feel free to ask!

[rtate]

I found a product made by "Quickcrete"

hXXp://www.quikrete.com/ProductLines/HydraulicWaterStopCement.asp

It does say it can be used on swimming pools..

What do you think??

[cbucner]

Use a 4 1/2 inch grinder with a smooth diamond blade the chip free one.
Cut a shoulder about 1 inch deep all around. Make that round hole a square
cut some lines about 1 inch apart parallel with the edge of that square kinda like slicing the inside of that square in 1 inch slices.
Make sure that all these cuts are about the same depth
To do that you can spray paint your blade, the side that you see when you cut
and let it dry a bit and then when you make the first cut the paint will
be removed by the concrete and voila you have a depth marker.
Next time you cut you will see how deep you have to go with the grinder running.
After you done cutting hit the slices perpendicular with hammer and chisel
or a chipping hammer.
They will come out easy and will leave you a nice same depth hole
Then fill with hydraulic cement if wet or other pool rated cement if dry
hope this helps

[rtate]

Thanks cbucner, that is a great help!!
When I look at the instructions for Hydraulic cement they say:
"only mix what you can use in about 3 minutes"
Should I be able to fill a 12' x12" square 1"deep in 3 minutes??

Also Shoud I use a bonding agent between old and new?

In the past I have used the bonding agent instead of water to mix the cement...

[waste]

Depends on how fast you can mix the stuff and how well you trowel.

I'm a little pressed for time tonight, but will answer more fully tomorrow, if you need.