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Posted: Mon Jul 30, 2012 10:16 pm
by tim m
Hi all. I have recently laid a patio with concrete slabs and have begun pointing with a semi dry mix 3:1.
I wanted grey joints to give a bit of contrast against the pale 'natural' slabs. I used some black cement dye to do this thinking it would dry to a paler grey. It has in fact stayed almost black, or charcoal grey at best!
I think it looks OK, although I did not intend it to be this dark. Her indoors is less impressed and I'm thinking about trying to rake it out and starting again to keep a happy household 
A couple of questions...
Is using a black dye in smaller quantity the right idea to get a grey result? (I couldn't find any grey dyes)
Is it realistic to rake it out so soon after doing it (4 days ago)? If so, what is the best tool/method for the job?
I have only done about a third of the patio, which is about 20 sq m in total.
Thanks so much in advance for any help/tips.
Tim
Posted: Mon Jul 30, 2012 10:47 pm
by digerjones
i would just carry on as you are, most black dyes go grey after a while, and then go to cement coular after a year or so.
Posted: Mon Jul 30, 2012 11:13 pm
by lutonlagerlout
^^ it wont be long before its grey
BTW blue circle cement normally dries up very grey
LLL
Posted: Tue Jul 31, 2012 3:48 pm
by mnlad743
tim m wrote:I wanted grey joints to give a bit of contrast against the pale 'natural' slabs. I used some black cement dye to do this thinking it would dry to a paler grey. It has in fact stayed almost black, or charcoal grey at best!
I think it looks OK, although I did not intend it to be this dark. Her indoors is less impressed and I'm thinking about trying to rake it out and starting again to keep a happy household
A couple of questions...
Is using a black dye in smaller quantity the right idea to get a grey result? (I couldn't find any grey dyes)
Is it realistic to rake it out so soon after doing it (4 days ago)? If so, what is the best tool/method for the job?
I have only done about a third of the patio, which is about 20 sq m in total.
Thanks so much in advance for any help/tips.
Tim
Keep in mind that mortar is always darker, regardless of whether or not it contains pigment, just after it is put into place. It will lighten as the mortar cures - this can take up to 28 days to reach a full cure but you should begin to get an idea of the colour after a week or so. The colour itself shouldn't fade unless the pigment used is made up from a Carbon Black - Iron Oxide should give you a stable colour.
There are a few 'Charcoal' grey pigments available, generally these are either a 'weak' black or a black pigment blended with some Titanium Dioxide (white) pigment. You will get much the same result by cutting back on your black pigment concentration, I've used them at anything from 1/2 of 1% up to the maximum recommended concentration of 10% (best not to go this high) in order to obtain different effects.
Posted: Tue Jul 31, 2012 5:11 pm
by tim m
Thanks for your replies, all very helpful although some mixed opinions on whether it is likely to fade.
The product I used was Cementone 'colours for cement'. Does anyone have experience of using this product, and whether/how long it took to fade to a mid grey? I don't have the tin at the moment so can't check what it was made from.
I used less than 5% pigment but that was obviously too much! I'm not inclined to try raking it out if the desired effect would be achieved within a few months so carrying on is the preferred option!
My wife is still quite insistent that she doesn't like it, but would maybe concede if I could say with some degree of certainty that it will fade over time.
Thanks again to all for taking the time to respond.
Tim
Posted: Wed Aug 01, 2012 10:06 am
by mnlad743
tim m wrote:The product I used was Cementone 'colours for cement'. Does anyone have experience of using this product, and whether/how long it took to fade to a mid grey? I don't have the tin at the moment so can't check what it was made from.
I used less than 5% pigment but that was obviously too much! I'm not inclined to try raking it out if the desired effect would be achieved within a few months so carrying on is the preferred option!
My wife is still quite insistent that she doesn't like it, but would maybe concede if I could say with some degree of certainty that it will fade over time.
Thanks again to all for taking the time to respond.
Tim
Tim,
It's much too early to judge the final colour - I wouldn't begin to consider whether it's too dark until it's been in place for at least a week or two and you probably won't know what it's really going to look like until it's been in place for a month. Therin lies one of the difficulties in working with pigmented mortar.
I've had a look at the Product Data Sheet for Cementone's pigment and they list it as a 'Ferric Oxide based powder'. That doesn't tell me a lot. In all likelyhood it's probably a mix of several oxides as most pigment blends are made up of a combination of different base pigments (iron oxide, ferric oxide, titanium dioxide, chromium oxide - the list goes on but these are the main ones).
They don't single out their black on the document to say if it's a Carbon Black or an Iron Oxide, or a combination of the two. If there is some Carbon Black in there, that will wash out of the mortar leaving a lighter shade of grey.
If it's a decent grade of Iron Oxide the colour shouldn't fade - but it will change over time as any exterior surface will due to the effects of weathering.
I know that there are people out there that say that all dyes (powdered pigments aren't really dyes at all, but people incorrectly refer to them by that name) fade. That's not true, but as you've seen the colour can change quite a lot during the curing process - that's not the same thing as fading. You would have been better served if you had made up sample batches and allowed them to cure in order to judge the final colour (if placed insde on a sunny window sill they would not have required 28 days to get an idea of colour).
Soil, the effects of acid rain, growth of moulds, lichen etc will eventually have an effect of the colour of the mortar - as it will of the surface of the patio or indeed any exterior surface regardless of finish. Also, because the mortar joints are lower than the surface - the effect will be seen there first.
Posted: Mon Aug 06, 2012 7:44 pm
by tim m
Thanks for the detailed reply Bruce, very much appreciated. I think I will leave for another week or so to get an idea of final colour.
If it is still too dark, I will try to take it out with a chisel and start again, possibly without any dye at all. It seems to have caused more of a problem than I ever thought it would, you live and learn!
Thanks again to all who have responded.
Posted: Tue Aug 07, 2012 3:33 pm
by mnlad743
Tim,
I wouldn't give up on pigments altogether - you can get some very nice results that don't look like they came out of a tube, which is why I like them. The key is to spend a little time testing before you use them in anger, as you've seen to your cost. The approach that you took is a little like walking up to the paint mixing system at B&Q and start to punch random buttons - while blindfolded!
Posted: Tue Aug 07, 2012 6:24 pm
by London Stone Paving
mnlad743 wrote:Tim,
I wouldn't give up on pigments altogether
I would
Posted: Tue Aug 07, 2012 6:54 pm
by haggistini
I would rip it out and use normal "gray" cement and not a semi dry mix
Posted: Tue Aug 07, 2012 7:31 pm
by dab49
Hi Tim, recently been through the same scenerio ( albeit, total refurb on a property,total landscaping front and back). The other arf picking up on detail( pulling my hair out!!),just an idea; tell her to rake out the pointing and you will re-do with any thing to her liking ,they soon change there minds, and if that don't work, buy her that shadey grey book ;no more worries about shades of grey on pointing on patio's!!
Good luck
Dave
Posted: Wed Aug 08, 2012 7:41 am
by mnlad743
London Stone Paving wrote:mnlad743 wrote:Tim,
I wouldn't give up on pigments altogether
I would
Yes, well we've had this fundamental disagreement before. The only thing we're likely to agree on is that the other is full of **** on this subject.
Posted: Wed Aug 08, 2012 8:12 am
by Carberry
mnlad743 wrote:London Stone Paving wrote:mnlad743 wrote:Tim,
I wouldn't give up on pigments altogether
I would
Yes, well we've had this fundamental disagreement before. The only thing we're likely to agree on is that the other is full of **** on this subject.
I don't think anyone is claiming that you're full of sh*t. It's more that it isn't worth the time or the effort for most contractors let alone DIYers.
Posted: Thu Aug 09, 2012 10:09 am
by London Stone Paving
mnlad743 wrote:Yes, well we've had this fundamental disagreement before. The only thing we're likely to agree on is that the other is full of **** on this subject.
ha ha. But I dont think you are full of shit at all (and I'm definately not full of shit ??? ) , I respect anyone who has got knowledge on a subject and you obviously know what you are talking about when it comes to pigments. I have been in and around the hard landscaping trade for best part of 15 years and I've never heard a good word said about pigments. I have also used them myself and didnt get along with them. If they were so good everybody would be using them. Bottom line is that there are other products out there that do a good enough job and are much more user friendly.
Posted: Thu Aug 09, 2012 12:20 pm
by mnlad743
London Stone Paving wrote:I have been in and around the hard landscaping trade for best part of 15 years and I've never heard a good word said about pigments. I have also used them myself and didnt get along with them. If they were so good everybody would be using them. Bottom line is that there are other products out there that do a good enough job and are much more user friendly.
I take your point, however, the pigments used by the commercial concrete and precast industry have only been widely available on the market for about three or four years. These are a 'different kettle of fish' to some of the off the shelf pigment products found presently at your builders merchant or DIY store.
You'd be hard pressed to drive down any street in Britain without passing multiple examples of the use of these powdered pigments used in other types of concrete - paving slabs, block pavers, roofing materials, pre-coloured render. They are also widely used by builders for use in colour-matching mortar on extensions as well as in restoration of historic and listed buildings both in lime and cement based mortar and render. Yet there seems to be an attitude within the landscape industry that once you lay them on the ground, pigments instantly become junk. Your blanket statement about avoiding pigments altogether was what I was objecting to as it seemed to be yet another example of this bias (apologies if that's not what you intended).
Pigments have their place in the market just as products such as Easipoint do. For those users at the DIY end - they can make up a coloured pointing mixture for half the cost (or less) of the products that come out of a tube. They also offer a much wider, and often, more unusual colour choice selection (you want Turquoise pointing - no problem!).
Having said that, they do require the user to be very meticulous (possibly anal) in their preparation - if you fail to thoroughly test ahead of time (as did the person who started this thread) they may well be disappointed with the results as he has been, there is no question that there are products that are more user friendly. In my experience however, those that have had problems using pigments have usually shot themselves in the foot - and try to blame it on the pigment whereas it's usually the fault of the 'loose nut behind the trowel'.
I can certainly understand why a contractor would choose the easy path - more than ever cash-flow and turnaround is all important. Most of these firms have as their bread and butter a standard 'stone' coloured patio. No reason whatsoever that they shouldn't use a product like Easipoint - I would (and have done).
The other side of the coin is the simple fact that contemporary paving design is becoming much more common as is the need for contemporary pointing colours - powdered pigments are able to meet that demand now, it will more than likely be several years for companies like Easipoint to see a big enough demand in this part of the market to support new product introductions that address this need.