If it stains concrete then it will stain hypertufa. If you put it in your mix before moulding, you will get a very even colour right through the piece, but you will need to add quite a lot. Or you can dissolve it and paint it on while it is curing and use much less to get colour only near the surface. It is much easier to control the final colour by painting it on and you can apply more coats as needed.

Ironite on its own will give you quite an orange rust-colour. Multiple coats will tend to give a darker brown colour. You can also try copper sulphate which is a little harder to find, or use them both for an interesting variation.

For speckles, try adding the dry powder to the curing surface. Tricky, you might want to try this on some waste bits of tufa first.

Despite appearances, this is not a plum pudding but a hypertufa bowl! It is a 1:2:2 cement:peat:vermiculite mix with some ferrous sulphate included in the dry mix. This produces a darker brown colour. I don't have a finished version but imagine it will dry a little paler and a little more orange.

{{gwi:75446}}

You might want to reconsider using Ironite...for anything. The company was sued in 2002 for making misleading claims about the safety of the product. While it is promoted as "environmentally safe", it turns out that it actually contains very high levels of Lead & Arsenic! Several oither "persistent toxins" were also found to be present in the stuff as a result of using industrial waste as the source for their "iron". Spread the word...and spread manure instead.

Here is a link that might be useful: Ironite Toxicity

An interesting case. The link you give still shows a page with the banner headline "Ironite Sued for Toxics in Fertilizer and False Advertising", referring to the non-disclosure of heavy metal levels in Ironite. What the ELF fail to publicise anywhere on their website is that they have settled the lawsuit on the agreement that Ironite Corp. would reformulate their product using safer materials, because there is a strange lack of publicity about this from the various pressure groups. I don't know whether the reformulation only applies in California where the lawsuit was brought, and I don't know what the levels of heavy metals might be in the reformulated product. Remember: the "anti" organisations are just as deceptive as the companies they campaign against :)

Perhaps this is a good time to mention vermiculite. Dozens of websites still declare that vermiculite is contaminated by asbestos, and this is repeated ad nauseam almost any place where vermicluite is mentioned. But of course the one mine where contaminated vermiculite occurred was closewd in 1990. It is of interest that even though the company that owned the Libby mine went bankrupt under a hail of asbestos lawsuits, the former owner and some high-ranking managers were personally indicted this year on criminal charges related to obstruction of the EPA investigating what is now a superfund cleanup site.

Where have I been! I never heard any of this about Ironite, guess I need to quit playing with 'tufa and get out more. Reading the article made me think about the brouhaha over using sterilized sewage sludge for fertilizer, lots of heavy metals in that too. The catch I'm seeing in a lot of these "contaminated" fertilizer/compost articles is that no one has yet shown that the heavy metals are available to the humans working with the material, the plants growing in the soil or that there is ground water or runoff contamination. That being said, ordinary precautions should always be taken when handling chemicals of any sort. Using dry materials, including cement, requires eye and lung protection. Don't become complacent!
Back to Ironite. The amount I have leftover is small, app. 1 pound and from a new bag. The color of the bowl in the photo is almost exactly the color I'm looking for, I think I'll give it a try. Shrubs, do you remember how much you used for that project?
Thanks for your input.

First thing to remember is that I didn't use Ironite so you might get a slightly different colour. I used ferrous sulphate, more often used as a moss killer than a fertiliser.

I didn't measure it out, but used roughly one quarter of the amount of the cement. The other ingredients in your recipe will also affect the colour. More peat makes it darker and more brown (although it will weather out paler over time), more cement makes it paler and greyer, the sand colour makes a difference too but not as much as you might think (I think it all gets coated over by the cement). Vermiculite makes the pale flecks which are nice in these dark mixes but don't show so much in a paler recipe.

I found a source for iron oxide concrete pigments which recommends using them at 3% of the cement weight, any more making little difference. I don't know how relevant this is to sulphate stains.

I believe that most oxides and other colors are recommended to be not more than 10% of the amount of the cement, to prevent later deterioration of the project.

Regarding vermiculite and asbestos: I remember reading several articles a couple of years ago that said that vermiculite and asbestos were often found together, and it wasn't really possible to separate them.

Heavy metals CAN be taken up in plants, depending on certain other conditions (pH of soil, other chemicals present in the soil, presence of acid rain, etc). They can also leach out of projects that contain them, which may not affect us, but can do some damage to creatures drinking from contaminated birdbaths & other water features.

Investigate what you're using, just to be safe.

Sue

what kind of colorants would be safe to use around fish? i want to use hypatufa to line my pond and to build the falls and walls that the plants will live in. i would like a dark granit like look. im new to this hypertufa. i did line part of my pond with cemnt with alot of sand in it and came out with what looks like dried sand or sand stone and its really rather crumbally. im wondering if i use course black sand, vermiculite and peat in the portland cement, if i can get the look i want. i would make a smaller batch of this that i would coat over the non colored hypertufa only in areas that will be visible since it would be very expensiv to do the entire pond with the color

parker