Ive been doing some research on venetian plaster, but have come up dry in my findings. I'm interested in learning the mix for true venetian plaster, as done by Orazio. Shown on <a href="http://www.oraziostudio.com/tech2.html." target="_blank">http://www.oraziostudio.com/tech2.html.</a> Now I understand he uses a Lime and sand with microfiber mix for the base coat, Which is then followed by color that consists of Lime, Marble dust, Linseed oil, Pigment and Marseilles soap. The color is then brushed with Marseilles soap and toped with beeswax.<br /><br />Now my question is the proportions in which this is done. Its to my understanding that Linseed oil slows the drying process. Other than that I don't know what the purpose of the soap is for. Please help. I need exact measurements for the Linseed oil and soap. I think as far as the lime and marble dust its 50% lime to 50% marble dust. Other than that i'm lost.<br /><br />Also its my understanding the Marseilles soap is dissolved into water untill its slimy prior to adding it to the plaster mix. I'd like the proportion for that also. Let me ad that I was recommended this board being said that there were to knowledged people on the subject. Thank you.... please help. <br /><br />One last thing.. please be patient with me. Let me know if ingridients such as maseilles soap can be substituted as i'm sure i'll have trouble finding this here in arizona.

This message has been edited. Last edited by: David.,

Hi Michael,



Welcome to Plaster talk!



Authentic Venetian plaster recipes will vary from Italian family to family and region to region. To say that there is a "true Venetian Plaster"...well which one is the "true" one? Let us try to dissect the one "as done by Orazio".



For the base coat use 50% lime putty and 50% fine brick or masons sand. Thats one part lime putty and one part fine sand. For micro-fibers, use short, fine polypropylene fibers. About one ounce per gallon of plaster is a guess. The micro-fibers are not essential to the success of the base coat. Their purpose is to create extra strength in the plaster and reduce the likelihood of shrinkage cracks from forming. If the base coat is applied about 1/8" thick or less--there is not any risk of it cracking.



You have no doubt seen on video how Orazio demonstrates mixing his finish plaster--the color coat. About 50/50 lime putty and marble aggregate, plus some linseed oil and Marseilles soap (Olive oil soap).

He uses several ounces of soap and about the same amount of oil per approximately one liter of plaster.

As far as I know, he�s not saying what amounts and keeps it all very tightly held. The amount of oil and soap is not a rigid formula and your recipe will not easily fail with varying amounts.



You are right that the linseed oil gives more �open time� by delaying drying. It also makes the plaster a bit more durable. Linseed oil is used in making oil paint. As it oxidizes it creates a rigid film that imparts some water resistance and a slightly harder surface than with no oil added.



He makes it clear that he does all his mixing by hand and just feels the right proportions--no rigid measurements are used. This does give it a romantic feel, as it seems more authentic. Does this mean that Italian manufacturers are producing inferior plasters? Certainly not! Yet, his approach is novel and has a certain appeal.



Most of us here do not have the time to consider making our own plaster, but do hand mix the earth pigments and of course use �Old World � application techniques.



I would try a recipe of 50% lime putty, 50% fine marble flour. Adding 4 to 6 ounces each of oil and olive oil soap per liter of product. You can experiment with the oil and soap figures as they may need to be varied, but these should be close.



You should use lime proof pigments too. Earths or oxides are preferred.

Olive oil soap can be ordered on-line. You may find locally, Kiss My Face Pure Olive Oil Soap. Shave the soap into small slices and place in hot water. Not too much water, but enough to melt it to a thick oil like consistency.



Have a great time in your quest for the ideal plaster finish.



David

Hi all
May be this would help if not let me know. This recipe is quite flexible what mean you can suit to your requirements.

Whitewash : 1 volume of lime for 1 volume of water

Paints : 1 volume of lime for 2 to 5 volumes of water, according to the desired transparency

Strong water , or patinates , or glacis : strong water is saturated with lime, water being able to absorb 3,8 % of its lime weight. Strong water is transparent, and is used to water the dyeings, without changing the final dyeing.

Whitewash are used to cover, to fill fine cracks, the faience manufacturings; they have a load, thickness, and successive master keys do not bring to in no case an addition of colour, because it is a nontransparent mixture, contrary to the paints, and especially to the patinas.

The paints are paintings, whose binder is consisted lime; initially, this lime was sharp, today, one uses it extinct. Because of their transparency, the colors are added, from one layer to another.

In a paint, there is one sticking, and charges it. The load ensures the thickness, e.g. the precipitated chalk, it is chalk finely crushed.

Limes
The quality of lime is significant: the finer initial limestone is pure, and light (less density) will be lime, more its covering capacity will be significant.

Batidol has a density of 0,6; it is appropriate badly, and has a colour dew.

Lime Beats: 0,4; is appropriate well.

The lime paste Aimos (Greece) is excellent;
conditioned out of bags of 13 kg, it contains 8 water L, and thus 5 kg of dry lime, are a proportion close to 0,4; with a density estimated at 0,5, that gives a volume of dry lime of 2,5 L.
One finds it at " the fertile stone " with 44470 Ste Luce/Loire, 88, street of the station.

French Limes and Dolomites (53120 Neau Tel.: 02.43.98.23.78) start to market a calcic lime paste.
One can estimate that, for lack of measurements, its distribution in masses is the same one as Aimos lime.

The pastes have a density of 1. Therefore, 1 L, or 1 kg of paste contains 0,4 kg of dry lime, that is to say 0,2 L.

Except using lime paste, it is necessary to prepare the paint the day before.

The colouring paste must be prepared separately.

Pigments
Sennelier gives the list of the pigments compatible with the paints to lime. All the pigments "ground" are compatible. Metallic oxides also, but they pass with time.

One can use a randomly found mineral ground voyage. However, it is not at all obvious to obtain the color chatoyante which the ground collected offers. The really colouring particles are of an extreme smoothness, and it is what makes the difficulty of the operation. To recover, or insulate these particles, it is necessary to wash the ground, to let it elutriate itself, to remove water surface by siphoning, then with an adequate tool (trowel, spoon...) to remove the cream on the surface, by thus leaving side the bottom, which contains of course the heaviest particles. And it is necessary to start again, with the cream, in the same way, X time... to manage isolated the cream from the cream! that which will have a reality colouring capacity. If this operation is not looked after, one will find oneself with heavy particles, noncolouring, which will be visible on the surface of the paint. To fresco , that can pass, it will be enough to tighten, push these particles in the body of the coating (that can belong to an action wanted besides, sought); has secco , more question! and these particles will not be fixed for as much...

Then, this "super-cream" will have to be dried, in order to be able to weigh it, dry, to control and respect the threshold of stability (see hereafter).

There exists for the pigments two thresholds significant, to respect:

The threshold of stability
It is the percentage with beyond which the pigment will not be fixed by lime; this percentage varies according to the support. The ideal is to work has fresco , because, at this moment, the surplus of pigment can be fixed by the subjacent coating, by the limestone film on the surface of coating. With fresco , they is approximately 6 to 7 H after the application of the coating. It is possible to work with the pigment alone, without lime.

The threshold of saturation
It is the percentage of pigment with beyond which the colour will not change any more.

The table which follows is very significant. It gives the thresholds to be respected:

% max in mass of the pigment compared to lime dries
Saturation Stability
secco has

Whitewash
20
10

Paint
60
5

Patinate
100
1


With fresco , one can exceed the thresholds of stability indicated, until reaching 100 % (absence of binder), because it is the fine subjacent layer of limestone which will fix the pigment.

It is the ideal to work thus, the colour is reached immediately, and the lifespan is that of the coating.

With secco , the proportion between the pigment and the binder are very weak, in particular for the patina. Lime behaves like a pigment, as for the color, and that "breaks" the colour.

A paint, and more still a patina, are diluted, that gives the transparency to the layer, and it is this phenomenon of transparency which makes it possible to add the intensities of colours. For a patina, one will need many applications, at least ten, to obtain the intensity of the desired colour. The lifespan of a painting patinates has secco is twelve to thirteen years.

Additives
Wetting agents : maximum: 0,2 % mass binder
Ensure a better integration of the pigment in water.
Ex: milk, soaps (Teepol, black liquid soap), pine cone scum, certain vegetable oils.

Retaining of water : maximum: 2 % mass binder
Trap water, and restores it more slowly, later, like clay, in a mortar; what allows a better carbonation.
Ex: stick skin of fish, pectin of certain fruits, algae, adhesive with wallpapers, cellulose methyl.

Stabilizers : maximum: 5 % mass binder
It is a fixer, which supplements the action of lime.
Ex: casein (thus, milk is at the same time a surface-active agent and stabilizing), polyacétate of vinyl, "Lanco Vénitien" of Lafarge, alum salt (fixing in the short run, time that the carbonation is done).

Waterproofing : maximum: 3 % mass binder
It is one waterproofing, interesting for outside.
Ex: linseed oil, lards, stéréate of calcium or magnesium (they are also soaps: wetting agents).

Accelerators :
Accelerate drying, not the catch.
Ex: methylated spirits, white vinegar

Thinner :
The diffusion of the pigment allows
Ex: casein.

Application has secco
A paint applies only to one wet wall. The application must be done quickly, and without connections, if not that generates an overload color (the intensities of the colour are added).

It is necessary to apply a first layer, white, without pigment. Then at least two other layers, for the color. Between each, to leave a drying, which can take 1 day on already wet supports, or very little time on a porous and dry support, such plaster (note: on plaster, or wood, to apply an underlayer of adhesive to wallpapers, to stop the pores). The proportion of the additives, in particular that of milk, must be done while decreasing, or with equal quantity, from one layer to another.

It is definitely preferable to use lime paste; if not, as for the plaster, to powder on water, and to let the impregnation be done, before starting to mix. The grumeaux ones must systematically be reduced, this is done preferably with a heavy paste, nonliquid.

Example of receipt, for 10 L of painting:

5 L of paste (either 2 kg of lime dry)

2 skimmed milk L (dampening agent and fixer)

3 water L

100 G of pigment

The proportion of water is not extremely significant; like known as at the beginning, it exploits the transparency. It is necessary to carry out tests, and to see whether the wire of the brush appears, or not, if they is too thick, or not.

What imports, it is well to measure the quantity of lime, in order to determine the quantity of pigment, and the additives (to refer to the table).

The pigment must be prepared separately, by measuring its mass carefully, compared to that of the dry binder; while working has secco , one must thus be limited to 5 %. Then it should be mixed carefully, in a little strong water, in order to gradually obtain a perfectly homogeneous paste, which will be integrated in the paint being prepared. With new, to mix perfectly, with an electric agitator.

During the application, systematically "touiller" with the brush bottom of the bucket.
marionova

ifell of my chair SSSSSSSSSSSSSSSSSSSSSSS

Please tell me people don't go to
all that work.
Ken.

ok, so there is somthin to keeping it simple? unless you like making it from scratch...hmm let safra create and make then send me the finished bucket to apply...
I love the simpler things in life (Safra).

The 'aggravation factor' wins out every time! Safra rocks!

Hi everybody! I recently saw somebody discussing my technique. I just wanted to say a few things to clarify: David says venetian plaster changes from region to region- which is not accurate because venetian plaster is a unique technique developed by Palladian artisans in the Veneto region of Italy and it is unique to that region. Over recent years there has been an enormous mass production of venetian plaster and there are hundreds of "labels" and manufacturers. Unfortunately, the true technique of venetian plaster is a lost art in Italy as well. Another person in your forum says she doesn't need any soap or wax on her plaster. I understand because the resin component of the plaster she uses makes it shiny. If you're using lime based plaster the olive oil soap solution will penetrate the plaster sealing it. The acidic soap also bonds with the alkaline, forming a new compound that is more water resistant. After this, traditionally, the walls were "ironed" with hot trowels... but enough for now. Orazio

Nancy- But you don't prepare your own plaster. Do you know what exactly is in it? Sorry, but I've been mixing plaster for many many years (in Italy) and I know what I'm talking about.

Nancy,Well said.Ken.

“Authentic Venetian plaster recipes will vary from Italian family to family and region to region."

Hello Signore,

If Venetian plaster (recipes) did not vary, then there would be no differences between brands of VP. They would all be equal -- non e' vero?

Even your plaster recipe varies, as you are imprecise in your measuring and mixing. This is not necessarily a bad thing, but it does not produce consistency. We believe that consistency is a desirable characteristic.

“Lost art”? It can not be lost if it is being taught and used today. Many individuals and schools teach this art of application across the US, Italy, and Europe, with Safra and SOIP being two of note.

Do not think that you alone are the only one with an understanding of this great Italian art.
Your contribution is appreciated, but you do not stand alone in advancing the current state of Italian plaster technique and Venetian and Italian plaster production. Most of us are too busy applying these beautiful finishes to be troubled by making our own product.

I wish you well in your production and application.

David

Where you been David? nice to see you back.

about the plaster mixing,....its like,...I can make a really good pizza here at home if I wanted to,...but I would rather just go to Trotta's and buy theirs.

knowhatImean

Fritz..now that's an analogy I can relate to.
I guess the bottom line is where one finds their "bliss". For my very short and sweet time applying plaster, the fun begins with a
loaded trowel of awesome product. I'm not particularly vested in all the intricacies that went into the product. This computer comes in handy but please don't tell the minutia of how it is made. ( No disrespect to those who are equally passionate about their computers )

Thank you Mario Nova for this information This has been hard for me to find also.
Michael Angelo Was just looking for info and got it.
But wow, cut someone a break for giving great information in this Technical Section of the forum.
Thanks again Mario

This message has been edited. Last edited by: Sean Brown,

Hi Nancy
The reason I found this site was to more completely understand plaster characteristics. i.e. to extend open time or shorten it, or color saturation levels, so I can adjust the plaster such as tone on tone, or the way soaps and waxes react with the plasters. You know, the how and why, so I can better serve my clients. I have no doubt that Safra products are excellent, but no one has everything for everyone. Being in the faux finish business for twenty plus years, I cannot see taking the class to buy the product, but I do understand the policy on proper application. I love mixing paints, plasters, and stains, and it takes less time then waiting for UPS.
Thanks Sean