Page 1 of 1
Posted: Thu Jul 24, 2008 1:37 pm
by james_joe90
Hi,
I live in wales and my garden has Welsh stone walls like this :
I've purchased balustrade and yorkstone slab moulds, but would like to cast a natural looking finish in keeping with the welsh stone - ie not simply grey cement.
Is there a colour anybody would recommend dying cement, to suite welsh stone ??
Also is it possible to mix different cement dyes to achieve an uneven multi-colour?
I understand cement dye must be dry mixed first. So i assume multi-colour finishes are achieved by roughly combining wet mixes of 2 different colour cements...is there a trick to this?
i'm thinking, either fill the moulds using two different colour wet mixes. Or putting two different wet mixes into the cement mixer, turning it on for a short period - enough to mixed randomly but not fully blend.
Would really appreciate any advice, as the sun is finally shining 
Cheers
Posted: Thu Jul 24, 2008 3:02 pm
by TheVictorianCobbleCo
I use Harristone and their service is top notch. The have a range of colours and can point you in the right direction re pigment colours. In a 2 colour mix mix your dominant colour in the mixer (the colour can go in last quite happily) and when evenly coloured pour into 2 wheel barrows. Now do a (half)(third) mix inthe mixer and put in the complimentry colour. Once evenly mixed divide between the 2 wheel barrows. Each wheelbarrow should now have a sunny side up fried egg look. Take a smaller spade/scoop and ROUGHLY turn the one colour into the other. Put into your mould and Vibrateto release the air bubbles. Good luck, any more detail and I'll have to sell you a franchise.
Posted: Sun Jul 27, 2008 7:04 pm
by Tony McC
Billy beat me to it, but I was just about to say that what you're proposin' (as Status Quo once warbled) is quite a complex operation, the sort of thing normally done by highly experienced mould makers with years of experience in concrete technology.
The mould itself is a major work, and then the knack of combining two or more colours of concrete *realistically* within the one mould is an art that several manufacturers have still not really mastered, despite their claims.
Judging from the photie, I'd go for a buffy-grey/green, similar to the colour Westminster Stone use for their Old Lancashire flags, and then use an antique release to darken the 'joints'.
Whatever you do, it's not likely to be terribly successful on first attempt. All concrete products, whether cast or pressed, take many many attempts before they come anywhere close yo what is actually required.
Posted: Mon Jul 28, 2008 8:06 am
by james_joe90
Hi Guys,
Sorry for my delay...I recently had a hernia op so not been very mobile - perhaps I'll have to tackle this job next spring LOL.
Thought it's a difficult process. Some retail slabs i've seen are aweful - almost leopard skin print. I'm after subtle changes in colour. But I'll give it a go and see what happens....British tenacity!
What did you mean about the antique release. Is this a special mould release agent which lubricates the mould, but causes minor staining where it collects in corners resulting in a more weathered finish?
I'm considering these colours :
Main colour - Buffy Grey Green - perhaps old york green.
Variables - Plum and Buffy Orange.
I noticed in Welsh stone there are hints of purple and orange.
If folding fails, i might blend the dyes at different ratios(by weighing them) to make say 10 combinations. Then per mix, use one of the 10 dyes. Due to the vast area i'm covering, I shall hopefully make enough to shuffle for a random effect.
I've seen natural slabs that are solid colours all varying like this and it looks rather nice.
Thanks so much for all your help, I appreciate your knowledge and experience.
If i discover a good combination of mixes i'll post them up here for you all.
Best wishes,
James
Posted: Tue Aug 05, 2008 3:44 pm
by mouldmaker
If you're filling your slab moulds by hand, make up 2 complementary coloured mixes (Don't try to make them too different, subtlty works best). Put a jollop of one colour in the mould, 2 jollops of the other. With a gloved hand, get stuck in and try to make the two colours blend into one, covering the whole surface, then fill the rest and vibrate. When you turn them out and they cure, you should find you get natural variations in colour rather than the leopard-skin effect.
Balustrading generally looks better in a single colour. To get the natural look, plaster them in a mix of yoghurt and cowshit and get some stuff growing on it! A little bit of soot will help themn look older faster too.
Posted: Thu Aug 07, 2008 2:46 pm
by james_joe90
Hi thanks for the tip - i'll give it a go.
My dad also recommended the yoghurt trick - although mixng it with cowshit whill encourage me not to eat it instead LOL
We've got plenty of soot, so hopefully i can get a good finish.
like you say subtlety works best.
thanks so much everyone for your advice...will email my progress.