Hi everyone, I am a artificial rock contractor (pool and spa) and an expert with specialty concrete mixes - specifically vermiculite which is also commonly known as "pool base". I have read through this thread and there are a few things I wanted to offer some clarity for: 1) The reason that you should pre-water the vermiculite is becasue vermiculite is incredibly absorbant. If you do not pre-water it will leech water from your concrete depriving it of moisture and likely leading to hairline cracking and crazing if the surface layers. The mix itself can still be "dry" as someone eluded above that concrete that is too wet becomes weak. This is extremely true. Pre-watered vermiculite is much easier to proportion and regulate the water in the mix. 2) Soap in concrete mixes is an "air entrainer" as discussed in a post above however soap has long since been used as an ingredient in vermiculite concrete mixes for different reasons. Vemiculite concrete is very sticky and can be difficult to trowel. Adding a tiny bit of soap, like dish soap, makes the concrete smoother and less inclined to cling to the tools. 3) It was posted above that concrete for construction does not get adjusted for water content. This is not true. Concrete is and can be adjusted on the fly in almost every mixing condition to account for changing conditions, heat, direct sunlight, concrete consistency, slump etc. There is a point past which you should not hydrate the mix but before that it is no problem at all to adjust slump. Every single mix through a mixer gets individually watered. Ready mix concrete will ask you if you are happy with the slump of the mix when they arrive to your site and will wet it up if you want them to. 4) Use water reducer to achieve desired placement slump without compromising the strength of the concrete. A tiny bit too much water equals a substantial loss of finished strength. 5) The best release agent for silicone is wax based release agents. In most cases if you are not sure what to use you should use wax based. I hope this info helps some of you out. If you want more information on lightweight concrete mixes check out the link below Here is a link that might be useful: Lightweight Concrete Mixes

Thanks for the ideas TE and Jo. That rock making class must have been fun. Sounds like you didn't need much prep work for the latex. It may not have been necessary but I gave my rock a good scrubbing and coated it with Murphy's oil soap. After imbedding some nylon mesh with a couple more layers of silicone I peeled the patch off yesterday. Only a small amount of rock pieces stuck to it but it was still quite tacky. Maybe I didn't blot the soap off enough. I made sure to do thin layers and waited 24hrs between them. It's less sticky today but not nice and firm like the top layer. I didn't bother with adding acrylic paint to the 1st layer but did with the next 3. The edges are nicely feathered though. I'd like to attatch it around a 2" dowel and use it like a paint roller if it cures a bit more. TE, tour brick faces sound neat but I'm definately looking to cast them in one shot. Guess the wax wouldn't be a good choice for this project. I did try casting on some 3/4" crushed stone and some woodchips covered with plastic but I didn't like the plastic bag lines around the indentations. Pea gravel would probably be better - it's probably smaller than what I used. Also using handi wrap instead of a garbage bag might make a difference. I haven't seen any 18' wide plastic wrap at the supermarket though. I'm not looking fot a very pronounced texture for driveway pavers. I'm sort of going for the tumbled paver look and am also trying to incorperate rounded corners in the mold. If we weren't making so many I'd take a file to the edges but DH definately wouldn't go for that. I made a mold with 2x4's with mini blind slats glued around the top that worked OK but I don't know how well it will hold up with repeated castings. I checked out the styrofoam at Home Depot - $12.98 for the 2'x8'x1.5" but they were out of stock.... wish they had it in smaller pieces so I could try it out before investing that much. There was a previous discussion about concrete sticking to various types of styrofoam but I can't find it. I think I remember you saying it doesn't stick to the kind you use. Is this correct or do you use a release agent ?

Yay! Someone likes my bathroom! You have no idea how I had to fight contractors et al to see my vision! Unfortunately, my vision has things like floating cork flooring.. (no glue down, as the rep from Torleys told me that the trapping of moisture is more likely with glue down), to slate, that everyone told me would need to have the heck sealed out of it continuously (turns out it's on a "need-to-do" basis, probably every 6 months to 1 year). I sealed the slate 3 times, twice with a paint roller LOL, just to make sure it was sealed. It's so sealed, I can't wait for some of it wear off the 2" x 3" tumbled slate floor. It's a little slick, when you add shower gel (no bar soap allowed in our bathroom now, as it adds oils that you don't want to build up). For 3 months after we bought the slate, and before it was installed, I had literal nightmares over the fact that I thought it was going to be COMPLETELY black in the shower.. it's not!! We added one shower light in the middle of the shower, just to calm my nerves, and I am very glad I did. It highlights every aspect of the lovely stone, without glaring at all. The picture above is with natural daylight on a snowy day, so you can see how NOT dark it is! The other "issue" we had with the slate was that it was/is randomly thick. Some were 1/2", some were 3/8" thick, and some were over 1/2" thick. The blacker tiles are harder stone, and of course the reds/oranges, are less so, but still we were able to cut them down even as thin as 3/4" for trim around the window. None of the strips snapped. The slate is called African Gold, made in India. It truly is the hardest slate I have seen. So far no shaling off of pieces and no crumbling. The worst thing if there was anything bad with it, was that two boxes we bought were completely cracked in half, but we used them in the archway (that is a foot too high.. long story!) Originally the door way into the shower was far more of a "hobbit" style, but I was vetoed, and I caved.. last time that happened on this job! We do have a window in the end of the shower, but the glass is a textured?/frosted glass, so the outside light is muted somewhat. I did have a moment of worry, once the slate was up, and knew that the paint colour would darken the room somewhat. To a degree it does, but all in all the room is cosy, warm, and a million times better than the room we had! And it has a... door! Our old bathroom had a bifold closet door for a door, and it sucked! The alder door we have now is a perfect compliment to all the "golds/warms" we have. The bathroom, although gutted to the outside walls is no bigger than it was before, but it seems miles larger now. It's still 9' x 5'. Our laundry room is part of the bathroom, but separated by a stud wall. A piece of advice..don't try and do too much in such a small space! Our machines are stacked, ginormous, and ate up every inch of the space I had intended not only for washing clothes, but also the storage cabinets that I now cannot install! Ah well.. I'll just fold on the lovely new Desert Gold granite in the bathroom! I do hope you do what feels right, what you want, and most of all..what you love. I may sound like I just blundered my way through, throwing my weight around with demanding certain products, but not one of the items in that bathroom was put in without the "OK" of either tile experts (who greatly informed me on my choices, products, and practicalities), to visiting many many sites, stores and product lines when it came to the cork/paint/lighting. If I had not recieved the go-ahead from the proper people, none of these items would be in the bathroom. There will always be debate on all these products, but heck, I am old enough that these things will outlast me! After that, who cares? LOL Once we have baseboards up, towel bars installed, we're throwing a bathroom warming party.. you're more than welcome!

I had tried a penetrating sealer by Quikrete and it just didn't darken the counter like I wanted it to. So I was looking for something else. I used bees wax on my son's vanity. It looks great, for a while. I just don't think it would last long term in a kitchen. So, I was reading the Real Milk Paint site about 100% pure tung oil for my cabinet doors and noticed they mentioned using it on concrete. Lots of research later and I found out that boiled linsead oil is used on concrete for bridges, so since I really wanted food safe I figured tung oil would probably be ok for my concrete counter tops. Or, in other words, dumb luck!! Now, I just hope it lasts long term. I am debating on putting wax on top, but am not sure if I would have to strip it to apply more tung oil, and just haven't had time to research it yet. Boy that sure was a long ramble. Sorry! Did the Cheng sealer darken your concrete? I may have made a mistake not using it, only time will tell...... S