How to colour cement?

[Terry Pinnell]

What is the recommended method of changing the colour of cement please?

I have a few loose patio bricks and the existing cement is a bluish colour. I'll buy a small bag of ready-mixed cement this morning but if I remember correctly it's always either sandy or light grey in colour.

Does it matter much how I do it? Perhaps just mix a few drops of matt or gloss paint from old tins? Or would that seriously affect the stuff's ability to set, or its strength? Are there dyes or something expressly for this purpose?

BTW, how do most DIYers mix the cement with water? I plan to use a large sheet of old hardboard, although last time I recall that some of it washed off onto the lawn despite my efforts.

[harryagain]

You can buy cement colourant. However don't expect to get an exact match and it varies depending on how much you put in. And the colour changes as the cement sets.

[Martin Brown]

They won't be dyes - they will be light stable insoluble pigments that can tolerate the extremely alkaline environment of a cement mix. You can buy cement colours from various sheds or alternatively find a sand mixture that when mixed into your cement gives the right shade.

To do a nearly invisible repair you need to mix a small batch to colour match when set and drie dout and then reproduce the quantities you used fairly accurately for each working batch. I find it easier to mix from the base components of sand and cement to get a colour match. YMMV

Pour the water in from a watering can and fold it over.

[Tim Watts]

On Wednesday 19 June 2013 07:46 harryagain wrote in uk.d-i-y:

I can personally state that if black is added until the wet mix is a dark charcoal colour, it will dry to a mid-dark grey.

I suspect most colours will look a lot darker in the wet mix and will dry lighter.

[polygonum]

And the effect of different sands can be very significant.

[Tim Lamb]

For small quantities I use a plastic bucket. Load up the mortar mix, add water and stir with a garden spade.

Don't overdo the water and trap the bucket between your feet to stop it rotating. Chop down to the bottom and twist the spade; allowing water into the clear sector. Continue.... add water sparingly until right consistency reached.

>

[polygonum]

Then accidentally tip in far too much instead of the extra few drops needed, dispose of thin mud-like stuff and start right over again.

[meow2222]

Cement colourants except iron oxide fade & streak over time. Emulsion paint mixed in gives better results IME.

NT

[Rick Hughes]

assume you mean ready-mix mortar and not cement ? You need FEB mortar colour, looks like powder paint .... difficult to get consistency & colour match though.

A sheet of board, pile cement, make hole in middle (like a doughnut) add water and lift and mix mortar mix in from the edges.

If what you have is old, clean well, and ideally add a PVA diluted wash to where mortar has to adhere.

[mark]

Wet the existing cement. Then add appropriate colourant to your mortar mix until it matches the existing wet mortar. You will therefore be comparing wet with wet.

mark

[RayL12]

Mix dry on board. Create a doughnut shape with dry mix. Pour in an appropriate amount of water(less is best) and go for a walk for 10 minutes or, until most the water has been taken up by dry mix.

[Terry Pinnell]

Many thanks for all the helpful advice.

[Vir Campestris]

Check.

Not check. Pour in not enough, then walk around pushing the cement into the water a little at a time. Do it carefully and you can stop it escaping. Once you have a too-dry mix and no water add a little more and mix it in until it feels right. I mean,*everyone* knows *exactly* the right mix...

Andy

[sm_jamieson]

Or start wildly adding random amounts of sand and cement grabbed with your bare hands whilst slopping the stuff in the bucket all over your good pair of jeans ;-) Simon.