Concrete – How to make the concrete countertop smoother

You make the pillars using any round type of tube or pre made form. They are made from wood,metal or plastic.

This page (and this one) has an interesting product for making various forms for concrete pillars.

Depending on the finish- if you do not mind the crackled and holey look like in the small pillar on the left then you just pour the concrete into a form and leave it. If you want a smooth finish you need to use a "vibrating poker" which will remove air bubbles and separate the concrete from the aggregate making a smooth finish, like on the tall one on the right.

You can either dye the end product with some concrete stain or use a dye that you mix into the concrete it self. Either will give you various effects and they both last for many years.

Tips

• Concrete can be pretty expensive and it is really heavy but also the most durable. You can also use plaster or hollow columns to make it lighter and cheaper.
• When using concrete do not use fast drying concrete as it will be more brittle and be prone to cracking and possibly snapping in half. Use a concrete that is suited for slabs and using aggregate is highly recommended.
• Even though concrete columns are solid you should consider putting in atleast some wire frame reinforcement. A single steel re-bar down the middle is the minimum but making a triangular re-bar structure would be ideal. The purpose of this is in the event that the concrete does snap or break the reinforcement will keep it in place .So it wont fall over and hurt/damage anything around it.

Yellow line is where you need to go, make the form slightly longer on the meeting edges so the ends can be recut to a clean joint. the reason being, moisture loss in concrete will change the look of the slab were it looses it rapidly. This means at any joint in the form where water can leak out will force the concrete to cure differently. Caulking the corners will help fix the problem an will also radius the edges a little or more if you choose, when done in the right spots. This should be done on the meeting joint, but of course you don't want a radius where they meet, hence the recut. Have some 1/4" stainless steel rod to drop into the wet mix at the sink front to strengthen those ends. If you put any on the back edge, be sure you steer clear of the area where the faucet is drilled.

You may be aware of this already, but I need to mention this. Concrete slab tops are honed/polished like natural stone is. A stain can be added to the surface prior to honing to add a variation in color too. Melamine will give a good start, but the honing and polishing will give a fine finish.