Go back to previous page
Forum URL: http://www.truefresco.com/cgidir/dcforum/dcboard.cgi
Forum Name: Fresco Workshop Program
Topic ID: 19
#0, Fresco painting PROBLEMS explored!!!
Posted by Arty Clay Forever on 03-Apr-04 at 08:19 AM
Below is the conversation I was having with Ilia and wondered if spritzing the painting as I go to keep it from drying on the surface and keep it from cracking would work. However I do not live in a DRY climate like the west coast.
(sorry to be so long in setting this up admin...hope I did it correctly..but am doing a clay mural with a school plus my own work...it's piling up!!!)
artyclayforever-


*****
" already hydrated lime in powder form (Ca(OH)2)
>"
>I have a 5 gal bucket being delivered this week.
>...and I will report back some time. Getting to
>be a busy.


this should work for you, however be prepared for cracking, detouching, etc. until you will get the right moisture and mixture specific to your area and setup.

there is always a well tested "professional grade" fresco lime putty at:

http://truefresco.com/frescoshoppe

but before you get that try to achieve results with what you have.

ilia
***
NO Ilia....it's NOT available to me, because I live in Canada. I talked to a fellow a couple of weeks ago on the phone and he said they didn't ship to Canada because of the cost of the Customs.
CRACKING eh? Damn......well I planned on following Gary's rule of thumb....of 18 quarts per 50 lb bag broken down to a couple of pounds at a time.

My only other choice is to call Gary's CHEMICAL LIME KILN people in Vancouver and see if they would put a bucket on the bus for me.

Any more good news??????
***
any lime will crack if put wrongly, it is just cheaper to understand what makes it crack using inexpensive stuff. poor lime putty (made of whatever lime you can get) will give you lesser working time and lesser ways of "finessing" a fresco, but it will only make a difference after you have painted quite a few already...

ilia
***
...so I try 1/4 cup variations in the water, weight the lime in a scale like I would a glaze.

If it cracks is that mostly from drying to fast. what if I spritzed it with water as I worked.....not wet....but not drying either...think it would make a difference?

I have been doing a few test pieces on plaster with acrylic colour washes....don't laugh....I thought the feel of the brush on the plaster would be about the same in a general way. ???? What do you think?


#1, RE: Fresco painting PROBLEMS explored!!!
Posted by Ilia on 07-Apr-04 at 12:20 PM
In response to message #0
technicaly you need 8:4 ratio of sand to lime for your lime coats (upto arriccio)and 8:5 for intonaco (painting plaster layer). On a Small panel and/or tile used for practice purposes you can skip scratch (base rough lime/sand/cement layer) and start with arriccio+intonaco

for the ease of experiment/learning stucco a section of the wall 4X8 or so feet leaving it really rough:

see "Albuquerque Fresco" topic for some pics of a scratch coat:
http://www.truefresco.com/albuquerque/preparation_albuq.html

This will help you to practice applying plaster and what not, you can scrape it each day and start new untill you are ready to move on.


>...so I try 1/4 cup variations in the water, weight >the lime in a scale like I would a glaze.

not clear on what do you mean here...

After you have turned your dry (for practice you can use any lime including the one sold in home depot) lime into a paste - of a heavy sour cream consistency take 4 cups of it and mix with 8 cups of dry sand - this will be your arriccio. For intonaco you will need 5 cups of lime to 8 cups of Fine (sifted through window screen) sand. You DO NOT need to add water it will be just enough in the lime putty. Use what's called "Plaster Sand" for your plaster home depot or masonry yard sells it, NO SILICA SAND. Prepare your mixes day before use.
(directions in "how to make lime putty" topic in Cafe al Fresco)

If you have the "scratch wall" prepared than soack it in the evening with water and in the morning it should be ready to receive plaster without additional soaking - it should have a consistent wet-gray color, if there are dry-looking (lighter gray color) patches than you did not soak it enough the night before - if there are not too big you can perhaps mist from the spritzer bottle undil they dissappear and do not come back in 20-30 min.

No you can apply your arriccio - you should not need to add water to the mix you have prepared but you need to "rework it" before applying, it is allowed to add just a little of a lime water to make the mix a bit softer - a little > for 1/2 of 5 gallon bucket of plaster 1/2 of a small cup of lime water... do the math for smaller ammounts of plaster.


#2, RE: Fresco painting PROBLEMS explored!!!
Posted by Arty Clay Forever on 13-Apr-04 at 04:32 PM
In response to message #1
Hello Ilia, thanks for taking the time to answer.
1. I thought I could weight out several lots of lime (as I would when testing a glaze receipe)and test by adding varying amounts of water...hoping one would work really well.

2. In all my reading I did not take in the fact that so much sand was added to the final painting layer, I thought it would be almost pure lime...a smooth painting surface.

3. Anyone who has had experience will have a "giggle" over this.....not having an experience, I mixed up the lime putty last Friday and today I finally used it. BUT didn't wet down the boatd and didn't add any sand.
Thought I would try what I thought would be the final coat. It's raining here and my studio is dry (I think)..but not dry as in California. The lime putty smoothed out real nice and stayed damp for a long time...in fact I had to wait awhile before I tried painting. Got pretty muddy in the beginning.

Ilia...YOU ARE CORRECT...it CRACKS!!!! Really bad!
But tomorrow is another day...and I'll scratch up the board , wet it down tonight and try again tomorrow.
ct


#3, RE: Fresco painting PROBLEMS explored!!!
Posted by Arty Clay Forever on 13-Apr-04 at 04:40 PM
In response to message #2
artyclayforever
FORGOT A QUESTION:

I am sure I have white (buffy colour mix of crystal and dark grains) silica sand that was given to me with other glaze ingredients.
What happens when silica sand is used as apposed to the sand you buy and a plaster/cement shop?


#5, RE: Fresco painting PROBLEMS explored!!!
Posted by Ilia on 16-Apr-04 at 05:26 AM
In response to message #3

>I am sure I have white (buffy colour mix of
>crystal and dark grains) silica sand that was
>given to me with other glaze ingredients.
>What happens when silica sand is used as apposed
>to the sand you buy and a plaster/cement shop?

Silica speeds up the setting of lime hence giving less time to paint, also it is somewhat too "slick" for lime to adhere properly which results in weaker plaster and detachments.


#4, RE: Fresco painting PROBLEMS explored!!!
Posted by Ilia on 16-Apr-04 at 05:17 AM
In response to message #2
>2. In all my reading I did not take in the fact that
>so much sand was added to the final painting layer, I
>thought it would be almost pure lime...a smooth
>painting surface.

Lime putty by itself has no strenght. what keeps the plaster together is the sand, lime adheres to the sand and so on so on, just like glue...
The smooth painting surface is achieved by troweling...
The smooth part will be a "thin layer" on the top what is known as "skin" that is a result of passing the trowel By "thin layer" i mean microns not even milimeters. (Over-troweling, however brings out "fat" - you will see it collecting on the edge of the trowel - you will need a rug to whipe it off before the next pass of the trowel, do not over-trowel it weakens the plaster - everything is good in moderation)

You perhaps missread the source or what is more likely it was written by the person that had no idea/experience of painting in fresco, i have come through hundreds of such books, in fact about 95%.

look for the old book (1947 or so) by Olle Nordmark
(american artists group, inc)

(however, nothing beats hands on workshop - you would be amazed how clear it becomes. we bell be teaching 2 in may and 2 in june go to http://frescoschool.com exact dates will be up in a couple of days. or call 310-337-2783)


#6, RE: Fresco painting PROBLEMS explored!!!
Posted by Arty Clay Forever on 16-Apr-04 at 08:41 AM
In response to message #4
Thanks for answering the silica question.
I have found washed playsand that says on our local hardware computer that it is not silica. It is very fine so will do for the final coat.
When I have a minute I have another couple of questions for you.

One more thing....I would love to take the workshop but you are a long way off.....and in a whole different set of dollars. Maybe someday.

I have never added my web site because it seemed like advertising,(where is the embarrassed 'smilie' when you need one? ) but in case anyone is curious:
WEBPAGES:
http://collections.ic.gc.ca/waic/collection.htm#t

http://www.caroltaylor.thedrawlyn.com

http://www.umoncton.ca/gaum/hpluc104.html

http://www.umoncton.ca/gaum/catalog/delta/delta_p10.html
(plus pages 11 and 12)

http://freshpilot1.nbed.nb.ca/
http://freshpilot1.nbed.nb.ca/taylorartstudio/index.htm


#7, RE: Fresco painting PROBLEMS explored!!!
Posted by Arty Clay Forever on 30-Apr-04 at 05:16 PM
In response to message #6
Well, I don't see any other messages here.so , I guess no one else is having problems but me!!!! That's terrific!
I am still experimenting...and the stuff is still cracking. I looked over your site again. I understood that the fresco would be quite thick...like almost an inch. Howver I notice in the panel the Ilia is painting of the woman and child in the sun that it very thin.
The cracking I am experiencing may come from being applied to thick. So I will change that....and see what happens.

QUESTION: if anyone is out there.....
Is their a physical way ..by eye or touch ...that one can tell the correct change has happened and that the colours are sealed in.

Since I work with clay I find it very difficult to keep my fingers off...even the ones that are finally very dry to see if the colour rubs off. Some of it does.
My studio while I painted last week was between 60 and 70 degrees F. I would forget to put more wood on the fire and it would drop a bit....then heat up. I found I could wait 2 hours before applying colour because it remained sticky. The last one I cut down on the water and it still cracked but it was really thick.

ONE MORE THING: while I was in Italy I saw what was called pieces of fresco for sale, they looked two inch thick and had a kind of "cheesecloth" between one of the layers (I don't think it was the bottom, seemed in the middle)...why would they use cloth?


#8, RE: Fresco painting PROBLEMS explored!!!
Posted by admin on 02-May-04 at 05:11 PM
In response to message #7
The thickness of the coats is as follows:

scratch (rough sand, lime, cement) coat - about 3/4 - 1 inch
rough coat (rough sand, lime 2:1) about 1/2 inch
float (arricio) (finer sand, lime 2:1) about 1/2 inch
skin or skim (intonaco) (fine sand, lime 8:5) about 1/4 inch + second (skin itself) about 1/8 inch
(Intonaco is applyed in two coats with about 15 min interval)

see more in "Albuquerque Fresco" topic on wall and plaster prep.


>and had a kind of "cheesecloth" between

what you saw is mesh used to prevent plaster from breaking, see "Albuquerque Fresco" topic about wall prep and deduct from there for small panel.

>Howver I notice in the panel the Ilia is painting of
>the woman and child in the sun that it very thin

that was just intonaco, the whole panel is about 1 inch.


#9, RE: Fresco painting PROBLEMS explored!!!
Posted by Arty Clay Forever on 31-May-04 at 05:47 PM
In response to message #8
If anyone's dropping by..
HELLO!!!!
I found crushed marble today!!!! size varies from 1/4" to at least an inch or more. I will screen it and use the larger chunks for something else.

Since no one is adding to this forum it must mean the whole world of painters in fresco have solved all their problems~~~~~~~~~~~~~grin~~~!!!!


#10, RE: Fresco painting PROBLEMS explored!!!
Posted by Gary sculptari on 31-May-04 at 07:35 PM
In response to message #9
I'm coming in late here - but I can help you.

You have to be aware of different sizes of sand. Silica makes the strongest mix, but a calcium carbonate sand will be weaker, fluffier, and therefore more absorbent. Calcium carbonate is marble or limestone. I checked on the net - Moncton has a huge limestone crushing plant, one of the tenth largest in Canada, and also silica. You should be able to get everything you need from Lafarge - including lime - just make sure its high calcite and air classified. Just like in sculpture, where the armature is the key, sand is as important as the putty. All lime has a chemical analysis - you want highest calcium as possible - any building lime will be close, sometimes though real cheap agricultural grades are out there - but they are never sold for building trades.

The final layer should be almost fifty/fifty putty and fine white sand - I use 'o/o' size in dolomite limestone - a softer sand than silica - this size is like table salt. Variances either way will create a sandier, textured finish, or a gummier finish which will crack slightly. Experience is the teacher. When you call Lafarge, get a gallon of concrete bonder too, to use between layers - it is a modern variation which works extremely well - but don't let it contaminate your surface - it makes a gloss.

SO like painting light to dark, warm to cool, in plaster you work lean (sandy/coarse/rough/thick/strong) to fat (lime rich/smooth/ thin coat). The first coat I use silica sand, the middle marble sand, the final dolomite/limestone sand - and three coats are more than adequate - expecially if the first is reinforced with galvanised steel mesh 'lath' (also from or directed to by lafarge).

I have never had a problem with drying time - but I have also found an acceptable 'secco' technique using potassium silicate (the ingredient of 'Keim' paints) - and also made in Canada, and fresco pigments. True fresco on fresh lime and potsil over 'green' lime are a marriage made in heaven.


#11, RE: Fresco painting PROBLEMS explored!!!
Posted by Arty Clay Forever on 01-Jun-04 at 07:24 AM
In response to message #10
artyclayforever
THANKS GARY, wonderful of you to take the time.
I have had to put aside the Fresco trials to finish a few other projects.
I have all the ingredients.....the La Farge in Moncton is where I went first...they certainly have a high calicum lime there...it's not white. Although it seems to become whiter with the chemical change.
I found some "beautiful white" from Quebec.

SILICA: I am positive I read somehwere NOT TO USE silica sand....which is damable since I have some with my pottery materials and spent a long time looking for clean non silica sand.(I thought sand= silica...but what do I know????)

Turns out Playsand is all that and I sieved the bag to take out all the larger 1/4" appromix pieces. Seems like I have everything plus pigments...now I need the time. The school mural and the movie will be finished soon. PLUS we finally have 20 degree weather...so everything looks good. It's been a long cool spring.


#12, RE: Fresco painting PROBLEMS explored!!!
Posted by Gary sculptari on 01-Jun-04 at 10:32 AM
In response to message #11
I am glad you are back on track.

If you are just playing around for now - with the concrete bonder you can adhere the final putty coat to nearly any stable (meaning non-flexing) but rough surface. Even if it cracks slightly, it still shouldn't break away. There is a limit of course. You will have to find your own limits - the norm is to avoid cracking. Drywall, however, cannot take the weight of the putty. That 'handibacker' concrete panel board 1/2", anchored to the wood wall studs, then expanded 1/4 mesh - then your three coats - that should be sweet enough. This is still removable too.

I also forgot to mention that the first coat contains cement more than lime.

One thing I like about fresco is that you can paint out of doors. After it rains, the fresco shines in its brilliant colours and with the fresh greens of the garden - splendiferous. Don't leave it out over the winter though. This is type of painting which will attract people to true fresco I think. Even if you leave them out, and repaint new frescos every few years - thats fun too (and good for business).

The biggest problem of fresco is weight. There is a special hand truck which can handle (meaning lift 8 foot in the air onto a wall) up to 150 lb slabs. You could use it like an easel. This is called a drywall handtruck - and you can usually rent them before buying. A 150 lb slab would be 15 sq foot if you are careful with your materials. I am working on new lighter slabs now though - we will see. The other option is to beef up the handtruck, possibly with some bigger, inflatable wheels (so it can travel rougher ground) - add the electric engine, and laser guidance system - wait - i'm getting carried away now!


#13, RE: Fresco painting PROBLEMS explored!!!
Posted by botticelli_angel on 07-Jun-04 at 03:25 PM
In response to message #12
Just a quicky...

Maybe two actually...
1,I have lots of spare White marble. If i grind it all down with a file, is this adaquet (sp?) sand for my intonaco layer?

2,What if i have walls that are old plaster or drywall, but instead of laying concrete or whatever method one may use to apply fresco upon such a space, what if i crosshatched with a knife, gouging the entire surface of the wall creating a tooth forthe plaster to stick to, then sanded it down smooth, would this be well enough for the lime to stick,and maybe get around having to go through one of the more orthodox processes?

Just wondering. Thanks guys, im just getting started, though passionate and in Love I am.


#14, RE: Fresco painting PROBLEMS explored!!!
Posted by Arty Clay Forever on 07-Jun-04 at 06:18 PM
In response to message #13
Hi angel, Gary and Ilia......

checked back over this forum and founds Ilia's answer to my silica question...it's #5.
Gary, maybe because our climate is so damp and the lime dries so slowly the silica works for you.
I'll have to try it when I get on board.

Angel I hope you are making a sculpture while you grind that marble down....

all thes best....


#15, RE: Fresco painting PROBLEMS explored!!!
Posted by Gary sculptari on 08-Jun-04 at 10:17 AM
In response to message #14
What I remember about the nordmark book - he throws away all his sand because a raccoon had walked across it ?!?! I could see this if the raccoon had 'sprayed it' - but no other reason. I do a lot of architectural restoration - specialising in terracotta and plaster - old time lime plaster, stucco. I see weak sand all the time -they used it to save money.

To grind the marble is a lot of work - it will have to be 'screened' too. I could tell you the equipment you will need (an 'assay' grinder) The coarse white marble sand is used locally here for ashtray sand, for high class hotels, and as a part of swimming pool plaster -they like its bright white, which hangs in as the 'plaster' starts to wear away. Check with these two sources. The pool places also have dolomite sand I think. Thought I saw some exotic sands at artstuff.com too. Most people just use the dolomite sand - not quite as white, but widely available. Limestone/Dolomite = calcium carbonate plus impurities. Marble = calcium carbonate plus impurities.

I already told how to use fresco on a strong, rough surface - use concrete bonder and diamond mesh. This is no different than a pure lime plaster (no gypsum) and was done for centuries, all over the world, the difference is that we add pigment as the lime is curing. Michelangelo had a lot of problems when he first started because they cured to slow, and got moldy/efflorescence. He started to add 'pozzolans' and brick dust - which we get in North America as fly ash. In Pompeii and India- they had to protect the fresco surface from dust and grime, and often used waxes, or highly polished the painted surface with like a spoon. They did this in the middle east too - they use a glass bottle. The Israeli artist on this list uses that technique. Timing is everything.

There are SO MANY ways to do fresco - you have to find the way that works for you, where you are - that is the true history of fresco. Fall in love with painting fresco - not the IDEA of painting fresco - don't look for obstacles that are not really there. Are we really so vain that we must treat every piece we do as a 'heritage' piece that will be treasured, and therefore must be gauranteed to endure, into the next centuries?


#16, RE: Fresco painting PROBLEMS explored!!!
Posted by Gary sculptari on 08-Jun-04 at 10:22 AM
In response to message #15
here's the sand link:
http://www.artstuf.com/stone-aggregastes.html

Shipping is always a headache.


#17, RE: Fresco painting PROBLEMS explored!!!
Posted by Ilia on 09-Jun-04 at 10:26 AM
In response to message #15
>There are SO MANY ways to do fresco - you have
>to find the way that works for you, where you
>are - that is the true history of fresco. Fall
>in love with painting fresco - not the IDEA of
>painting fresco - don't look for obstacles that
>are not really there. Are we really so vain that
>we must treat every piece we do as a 'heritage'
>piece that will be treasured, and therefore must
>be gauranteed to endure, into the next
>centuries?

Well said!

During our classes we teach the method we have used for years with great results - no detouching, no cracking, no poor paint adhesion.

student is welcome and encouraged to modify the steps and experiment later at his/her own time afterwards.
However they will always have the method that works - the one we taught.


Adding glue between the layers is not needed because if you layers did not stick by themselves that means that there is too much water in the plaster and/or the wall (panel).

(Gary, i should send you a panel prepped by student/s during the class - good luck trying to separate the layers.... the problem of shipping to canada is that your goverments hits shipper with rediculos customs bill a year later - the reason we stopped shipping lime to Canada. Why dont you fly to Baltimore MD and help us to set up the workshop there - we will have planty to discuss on August 18th - 22nd - we are starting 2-7 year freco community project in the cathedral there with initiation class this august, loggings will be provided for students ($100 - $20 per day) that is all the church wants for it's dorm fascilities!!! site will be updated with this info and we will start enrollment in a few days cost looks like to be $1549 without logging ($100 if student stays at the school dorm)

Silica - here is the theory covering some of the reasons of lesser "stickage"

silica is very hard and althow it is "angly" it's flat serfaces are classlike - slick when other sands will have irregular flat serfaces so lime will have more to "grab" on micro level.
Anyway why use it if it gives problems, whatever reason is the cause of them???? (problems in PAINTING, forget about sticking problems)
(more about silica in my thread with Gary: http://www.truefresco.com/dcforum/DCForumID1/114.html )


Here is a little about workshops forum:

if anyone asks here about why this or that happened on magnesium (dolomitic) lime or silica "inchanced" plaster - the answer is "Do not use it" for me it is like: will the regular car run on alcohol? perhaps. will it run better on petrol? yes. then why should we use alchohol to fill our gas tanks?