The cement

Because we carve into the damp cement mixture, it needs to be sand only, free of lumps and all other contaminants. The sand is well dry and is sieved before any mixing begins. Your choice of sand will depend on what is available to you so,...... my best suggestions include a fine and even grit, well washed and then dried, and seeing as I like a light coloured cement, the closer to white sand the better. You will see here that I use a lot of red powder pigment. Deep red works well to cover the not so nice gray cement powder and yellow sand I'm using currently. When I can buy true white cement powder (here in NZ I found a brand called Elephant white) and match it with white sand, one gets to really play with marbling the mixture. Having two brews of cement with different colours is a heap of extra fun and class to a project..... :-)

Above you see I've got a bright red colour and white base partially blended. Different mixture procedures make up the appearance of the finished surface.
What is really important is that you make a batch of dry premix big enough for the entire pour you are about to do. Aim to have a little left over rather than not quite enough to finish. Sieve EVERYTHING as it's measured into your pre-mixture mixing bowl. Aim for three scoops of sand to one cement powder. When that is well mixed you can then add sieved colour powders and lightly mix in. Use a table spoon of colour powder (no lumps) per litre of premix, and readjust from that starting point as desired....
This dry premix is then scooped into a smaller liquid mixing basin. A round basin that's nice for swirling your wee batch of near liquid cement. You'll also have a 1/2 bucket of clean water ready for use. Into this water we add a "smooth maker" additive called plasticizer. This stuff is a must! Add it per exact instructions on the bottle, then brew up your cement and swirl it to a near liquid state. Note that this method also ensures one had NOT got air trapped in the mixture. Liquidize mixing is also when the colours come into view, if you over mix now the colours will level out becoming quite consistent.... Only in your doing will you get a handle on what you prefer..... remember, it's all in the fun of colouring outside the lines that really counts right?... So, go for it.... :-)

Remember cement powder attracts moisture and becomes lumpy VERY easily. It is not a good look to have cement lumps so be mindful to avoid this issue where possible... You need to have air tight containers for each stash of cement you have. (one for your bag of new, pure cement powder and another for pre-mixes you may have left over from last time.)

Carving sand & cement

The profiles are your special tools for success. A well compressed bed of damp sand and carving down into it is our ticket to nice symmetrical impressions. Don't be in a hurry, turn the profile a few circles and scoop out the scraping with your spatula If you do damage the surface, just fill the hole and tap it back tight with your fingers / palms. Nothing difficult here just a little back breaking if it's a large item low to the floor....

Keep in mind that the sand will dry particularly if it's in sunlight. The surface can be wetted over with a pressure pumped sprayer This will also tend to stabilize the surface particularly if it begins to dry out... Be warned, dry sand looses it's rigidity and can fall away.... Don't allow your bed to get anywhere near dry, Keep it covered if you need to leave it for any time, and remember if you're away, your cats may leave you a wee present...!

Carving into freshly laid cement is a delicate task. Get too aggressive and you risk damaging the entire layer below. Your scrapping of cement are added back to your swirling mixture basin. A dab more water is added as desired.
You'll soon see how quickly the sand soaks up water from the cement, and in just a few minutes another layer of cement can be placed on top of the layer before. So, therefore we build up the sides walls of our dishes by applying a spiral of near liquid cement added in one scoop of the spatula at a time.

Right after we've finished with adding cement and carved down with the profile, is a good time to take away any / all bits of cement that have dropped during ones work. Then it is covered with a water proof sheeting (one that will trap the moisture under) and left to set overnight.

If you insist on working on it tomorrow it'll just be trimming the top edge up and getting it nice and level. Simply but carefully fill the vessel with water and it'll show where we need to remove the high spots. Using a flat sanding block with course sandpaper is good for this task.
Take your time to get this well flat. If it's lumpy don't blame me for breaking the dish during your plinth build. This flat edge carries all the weight, the weight of the sand pit above and the plint too.... Get this one right!

Leave the vessel in it's sand bed and covered for at least 3 days (the longer the better).... It needs time to harden up before lifting off the bench. Keep in mind that it is just a thin shell and it'll only take a light bump to break it...! So, be patient and wait till later.... Seeing a grown man or woman crying over a broken sculpture is tragic. I've been there, you don't need to.... :-)

To remove it from it's bed of sand, just take down the plastic perimeter first then shovel the sand back into it's storage container. Remember, do not allow ANY cement lumps to be mixed in with the bedding sand, so clear it of little bits before you do anything else.
We now carefully turn the vessel upside down and rest it on a sheet of thick cardboard on a wettable bench area. We're going to use a water hose to rinse with so this needs to be done probably outdoors where sandy water is no problem. Use a scrubber then a folded piece of course grit sand paper on the outside to lightly cut into the surface to bring out it's surface and shape potential. Go very gently on this, less is best because we can not replace what is removed....!

Gaps in the surface can now be filled by painting in a cement slurry.

Let this harden for a couple of days before I wet sand it off. Remember, perfection is not required here, tidy and rustic is acceptable. Only practice and experience as you go will improve your confidence in making a "really nice job of it".

Link to next tutorial. Cutting water entry hole.