In sketching and laying out subjects to paint last night, I imagined a new painting project I have in mind would look best in fresco. And you can't have fresco, or a cuba libre for that matter, without lime. But the lime I'm talking about isn't this of course.
It's this, the same stuff I use as a temporary base for laying out the more complicated marble mosaics, lime plaster putty to be specific. It's different than the stuff that goes on the walls in more modern US construction (gypsum sheetrock).
Two years ago, I made several five gallon buckets of this by burning hydrated lime that you can buy in the local hardware store in large stainless pots (which made some of it revert to CaO which is necessary to get the putty just right). Then I mixed the super dried powder with distilled water and saw more bubbles than a Michael Jackson birthday party.
Be very cautious though if making lime at home. I wore some goggles because when you first pour the water into the lime to make putty, it is reactive in a way that would make a mad chemist's heart warm. And, the resulting splash of lime in the eye would definitely ruin your entire day (and maybe eyesight).
In ancient times, they had very large holes dug in the ground (pits, I think they call them), in which they would toss crushed limestone and burn it with large peat fires. Then they poured water into the pit to hydrate or 'slake' the lime to make it ready to use on walls, pinatas, or a weird army of decorative lawn jockeys.
Two thousand year old frescos still intact and with vivid color locked in is testament to how durable lime is after it dries completely. It basically loses moisture and reverts back to limestone. So after drying, it's now limestone shaped how you want it and with the images you have painted. I imagine if you put your mind to it and with enough effort, you could even make limestone rocks.
If you have the lime and want to do a fresco of your own, you need inert ingredients like marble dust, sand, or perfect diamonds to keep the lime from cracking as it dries and to add strength. Lay down a base coat 10mm thick on a frame (or on a prepared wall) at about 2:1 sand to lime.
After the base coat dries, wet it down and put an 'intonaco' skim coat on that 3mm thick with a 1:1 sand to lime ratio. When mixing the sand and lime, resist the temptation to add more lime even though it looks very sandy and doesn't mix well at first, eventually it will become plastic-ish and spreadable.
Here is one I did earlier this year, the next one will be a bit more involved.
On a completely unrelated matter, does anyone see a typo in the latin below that I want to carve into some marble? I'm not sure if liquid paper or backspace will work to correct any errors in the stone, so I want to be pretty sure it is right.
P.S. - a super prize for anyone that can interpret all parts of the inscription above.
Some Like it Hot
5 hours ago