I'm late in reading this, but if you still need some help... When you first add water to your (proper) mix, just add enough to dampen all the ingredients, and mix it well. Then add a little water at a time until it is like a mudpie. You MUST mix it well, and your hands are the best tool (wearing latex or nitrile gloves). A little bit of water on the surface is fine. For a quick test to see if you have the right consistency, press a handful or so into a regular paper cup, filling it about 3/4 full. Immediately turn it upside down and rap the whole rim smartly on your table to eject the contents. If you can see any cracks in it, you either need a tiny bit more water, or it needs to be mixed better. If it slumps more than just a little (a little is okay), you've got too much water in it. Once you get it really right, you will know from then on. It's a practice thing. Just don't think it's going to set so fast that you don't have time to mix it thoroughly. Mixing is very important. Press into your mold. For corners and details, put small amounts in first, then by double handfuls, pressing firmly into place. Let set in the mold just long enough to set. Check frequently until your fingertip leaves just a slight depression. Unmold very carefully now, (it's still very fragile) to expose the surface you want to smooth. Now, burnish the parts that will be visible with the back of a tablespoon/soupspoon/serving spoon (not the measuring type). If you want to carve a piece, this can be a good time to try it, too. Pourable concrete is only used for large concrete work, patio slabs and freeway overpasses. I can't think of anything that we at this website do that will take that much water. Always remember that too little water, or too much water, will make a weaker concrete. It may not show up immediately, but it will do so eventually. The 3:1:1 recipe above is best for most purposes; when you know more of what you're doing, and what effect you're trying to get, you will know better which way to go. Perhaps more more than any other material, mixing concrete is best learned by actually DOING it. Mistakes are useful for burying in the dirt along your gate-line to keep the dog from digging out. ;-) Also be aware that there are different types of sand, and finer and more coarse grades. Sometimes sifted (by you) play sand is better than a coarse white silica sand. I find that sand with different sizes particles is a real headache to use. If I'm forced to use it, I will sift out the fine stuff and set the bucket of coarse pebbles aside for some future surface effect. Have fun! Sue

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

You can get a finish like polished marble if you take the time and do the work. There are several approaches but they all involve basically polishing the surface. This can be accomplished regardless of the aggregate, but the finer and fewer...the easier the polishing is. Large, hard aggergates require very aggressive polishing. The beautiful Terazzo floors that have come back into fashion lately are an example of big, chunky aggregate in a mortar bond that is highly polished. But a combination like that requires a diamond polisher and a lot of work. Reducing the aggregate to extremely fine sand or a "microaggregate" such as flyash permits polishing with sandpaper and a great deal less elbow grease. Cement pastes are relatively easy to polish...it's the aggs that are as hard as...well, rock. 'Cause thats what most of them are. Little rocks. You can build up layers of a paste-type mix on a 3-D shape by actually painting them on until you get the thickness required. However...curing must be under absolutely ideal conditions or it will crack to pieces. Pastes must maintain near perfect hydration throughout the entire cure or they will fail. But if you can overcome that hurdle, you can start with an old wood rasp to knock off any high spots and then work your way through progressively finer & finer sand papers until it has a mirror finish. Wet sanding is generally easier and is much less hazardous because it eliminates the very fine and dangerous dust. Best of luck and be sure to let us see the results no matter how you wind up finishing it.

I thought vinyl was good for basements (or at least okay to use there) b/c of watching too many home improvement shows where they've put the vinyl "wood" strips on the floor, saying it was a better option than laminate flooring. I want to scream every time I see this hunk from Canuckistan finish a basement using fiberglass insulation and a vapour barrier. Vinyl in a basement over a proper underlayment such as Delta FL is unaffected by moisture and resistant to mould. This post was edited by worthy on Wed, Oct 9, 13 at 12:24