How old is your white concrete? It is more sensitive to atmospheric moisture and is usually said to only be good for 3 months or so, then it's compressive strength dwindles.

You might try the exact same methods using fresh gray cement, and see what happens. If that turns out all right, the problem might be with the age of the white Portland. But if the gray breaks too, there is something wrong elsewhere.

Three parts sand shouldn't be too much.

On this particular forum, I am always uneasy when someone says "pour". To make strong concrete, you need to use the least amount of water you can get away with, and if you are literally pouring it into the mold, I suspect you're using too much water, which will also reduce strength in the project. If you aren't already, reduce the water, adding it only gradually, so the mix is about the consistency of cottage cheese. If you grab a handful and squeeze it, it should hold it's shape without cracking (too dry) or dripping any water (too moist).

If you're soaking, may I assume that you aren't using any type of strengthener type of additive? Usually, soaking is not recommended if you are.

Also, if you're staining after only a week, you're doing it too soon. You need to cure the concrete for 28 days before you do any staining. I don't know what too-soon staining would do, but it's not recommended. It may interfere with the curing, but I don't know.

Sue

p.s. I just noticed that you are in TX. How hot has it been while you're doing these? Working with cement when the temps are over 85-90F during setting-up and curing (at least the early stages) will cause cracking and breaking.

Sue

thanks u for ur help. pour- i maybe useing to mush water. it seems that when its to thick i get more air bubbles.i try to make it so when i put it in my hand it doesn't drip out. yes i do tamper it. by cement isn't old i bye it as i need it . no i'm not useing a strengthener type of additive. what should i use? if i use a strengthener do i not put them in water?- ur right i'll stain after 30 days . temp is about 100 here. i try to do this late temp my be 90. but u no i make bird baths and they seem to come out good ? the white stuf isnt has bad and they never crack . i bush them off and the seem fine. i haven't tryed to stain them yet. i thank u for ur hope . did u see my molds i use? at http://photobucket.com/albums/y273/katyB2/

Katy,
What will you use to seal your concrete birdbath? A sealant or waterproofer? Beautiful work!

Laura

I cant seem to see the photos it says the album is empty?