My sister is a plaster maseter. She spent $800 to get a 5 gal of this shipped up from mexico. I started looking at the composition and realized I could easily mix some up for her. Seems like lime, polymer, fine grades of sand, color. What do you think, ever seen it? She had thought of using it to cast things, maybe a new bathroom sink and top for her.
this may be of use..it was in my bookmarks
Stuart’s Fake Tadelakt Recipe
Tadelakt is a very fine, very smooth, highly polished, waterproof stucco traditionally applied to interior surfaces in Moroccan bath houses, and which was originally used to waterproof the interior surfaces of cisterns. This formula is intended to imitate the result of traditional Tadelakt using readily available components, and a relatively simple formula.
This informacion was prepared by and is the property of Stuart Cornell (email@example.com)
2 parts marble dust
2 parts lime putty (wet) (that is: slaked quick lime)*
1 part white cement
1 part screened, very fine clean sand
Mineral pigments to desired color (dry color will be lighter than wet color).
Water mixed with the maximum recommended amount of liquid latex additive
Mix dry components well, then add the lime, and finally add enough water/latex mix to form a moist, plastic putty
Two liters of marble dust, two liters of lime putty, one liter of cement, and one liter of sand is probably enough to do a couple square meters of surface and to keep a little back to repair problem areas. If you are going to use several mixes to complete a large area, measure components precisely, especially the mineral pigments, to ensure final color.
*Quick lime is the highly reactive product of burning limestone. When water is poured onto quicklime there is a violent exothermic reaction. When the reaction is visibly complete the slaked lime will settle to the bottom of the container (metal bucket or metal drum), and the water will rise to the top. In a day or two the slaked lime will be a thick wet paste under a cap of the residual water. This paste is the material to use in this formula. Depending on how clean the quick lime is there may be stones and other debris in this paste. Pass the paste though a screen (like galvanized window screen, mounted in a wooden frame) to remove all large residual particles. Any pebbles, or other debris, larger than the head of a pin will make application of the Fake Tadelakt Putty very difficult.
Apply the Fake Tadelakt Putty (FTP) with a putty knife with a rounded end and no sharp corners, to green but very firm stucco or poured concrete base – probably not more than 24 hours old. Smooth and thin (3mm to 5mm or 1/8” to 3/16”?) with the putty knife, but do not over work. It might be better to use a polished, very hard, slightly convex stone to smooth and thin. For large areas this stone might be 10 cm (or more?) in diameter; for small or very curved (concave) surfaces, it might be 3 or 4 cm in diameter, and maybe more convex, it might even be like a slightly flattened cylinder for working the concave curves of a bathtub, for example – use your imagination . I often keep two or three shapes and sizes at hand for differently shaped surfaces: keep them clean. Watch (and touch) the surface carefully as it dries: vertical areas will probably dry first, but the areas that set up for polishing first will be variable, and perhaps difficult to predict: maybe it is one hour, maybe five, before it sets enough for polishing. When you pass the stone over properly set FTP, it will compress and present a very smooth and hard surface. If the putty is too wet it will continue to move and displace, demonstrating that it is still too mobile; too liquid. If the FTP is drying faster than you can work it, pat the FTP with a slightly damp sponge to help keep it workable (too much water will eventually wreck the putty and it will not cure strongly or bond well); sometimes I just wet the polishing stone for slightly dry FTP and this moisteners the FTP sufficiently. If the FTP is too dry it will not compress well or may detach from its base (the green concrete or stucco below) and crumble; in this case remove the dried putty, apply a dollop of fresh FTP to the affected area, smooth and thin with the putty knife – it will set quickly here so don’t think it will take nearly as long as the original setting did: when it is ready polish with the stone. Once the FTP is compressed and polished, leave it alone: ah, well, sometimes I go back over it again – but the dryer it is the less (none?) it should be touched: it will detach if you continue to work it when it is too dry. If you have properly prepared the FTP and applied it to a proper base, and if it is compressed and in good contact with the base, when it cures it will be hard and well bonded. Moisten the compressed FTP maybe four or five hours after it has completely set (with a wet sponge or a light spray), repeat this as often as you can for the first couple of days. I sometimes fill bathtubs and sinks and vigorously splash water on other surfaces after 24 hours.
When I am polishing large areas, like maybe a bathtub, I take off my shoes, put plastic bags tied over my socks and stand/kneel on the surface to be polished, and moving toward an exit I polish as I leave. Though walking with socked/bagged feet on already polished FTP is probably not a problem. I tried it once barefoot which worked well for the bathtub, but the lime burned substantial amounts of skin off the soles of my feet.
Working two square meters (20 square feet) is quite a job of timing and labor.
I polish properly set FTP by pressing down lightly into the putty with my stone and making small circles as I slowly move my hand left to right, then towards me and right to left (or whatever combination of directions to completely cover the entire surface to be polished). The circles, or other polishing patterns, will be somewhat visible in the cured FTP.
If you want to apply FTP to cured concrete, grind the entire surface well with a diamond blade, blow it off with a compressor or clean with a strong vacuum, and wet the concrete as thoroughly as possible for perhaps a day before applying the mix. One way to wet the concrete is to cover the surface with towels, clean rags, a blanket… and keep the fabric wet for this period. When you apply the FTP to the surface, the surface should not be wet, certainly not dripping or with any visible water remaining, but the base should be as thoroughly saturated with water as is possible short of this: to increase curing time for the FTP.
To prepare a new polishing/smoothing stone: Select a hard stone of approximately the right size and shape (from a river bed?), use a diamond blade in an angle grinder (BE CAREFUL!) to form a very smooth and slightly convex face on one surface of the stone, with the all edges carved into radiused curves to avoid digging into the FTP when polishing. I cut a handle on the opposite side by making two parallel and shallow (as deep as my fingers are thick? and two cm apart?) cuts in the side opposite the convex face and perpendicular to the convex face, then a third cut parallel to the convex face from the outer edge of the stone towards one of the first cuts to remove a piece of the back, then repeat this cut to the other of the first cuts, removing another piece of the back and leaving the ridge between the first two cuts as a handle. Another option I have read about is to epoxy a handle onto the back of the stone. Then in the angle grinder, put a cutting wheel for metal and fine polish the convex face of the stone. If your stone is too soft you might find it worked well to begin with but in a short time it will not polish the putty any more. If you examine the stones surface closely you will probably note that it is rough and pitted – a rough faced stone will produce a rough surface on the putty when you are trying to polish it. If the stone becomes rough, retouch with the diamond wheel, then re-polish with the cutting disk; if the stone becomes rough to fast, throw it away and get a harder stone.
G'day Steve..glad you joined in....Steve O listed that as a tadelakt job, but only he can answer that question.
You are entirely correct in describing the effect as more of technique than a product.( and are infinately more qualified than me to talk about it)
The similarities between Polished Venetian (true) plaster and the tadelakt product is the size of aggregate and then the "venetian plaster" typically (not always) has a marselles soap in it.
The use of the acrylic admixture reduces the adheasion limitations of the traditional products to the Non-traditional substrates we have today..ie Portland Cement based stucco's ect.
By the way..I trowel great on a slab..but put me on a wall and I trowel like a girl.
Now back to the general discussion on Technique....When I was in Rome, defacing the national monuments with my pocket knife to understand their concrete, I learned a few things.
1. At the ruins between the collosium and the forum there is a big chunk of coffered ceiling laying on the ground...What I noticed was the aggregate I picked out of it was the same as the marble chips I was standing on, which i presume were the chips from the marble colums ect.
2. On the back side of th same piece you could see the "paddle" marks where they patted down thier "mortar.
3. I came to the conclusion that they placed a "mortar mix" ( slaked lime, pozzalan, fine sand ect) on the coffered mould face and then patted in the course aggregate (larger marble chips) to create "concrete".
Cut in a cross section, these look identical to todays concrete...difference was in HOW they were applied. (and of course the lime instead of portland).
I would have like to picked pieces off the Pantheon as well to see the progressive use of pumice as it approached the occulas, but I think I would have been linched by the Cabinarri.
If any of you Fellow Concrete Knuckleheads ever get to Rome...Go to the Pantheon and marvel at the 140 ft wide, 140 odd foot tall un reinforced coffered concrete ceiling with a dirty big hole in the middle..It made me drop to my knees the first time I gazed up at it....and made me feel like a "concrete hack"
steve manby said:we have done extensive interior and exterior Tadelakt work with Stucco Italiano's product which you can see here
Interior Exterior Lime Plastering