Cennino d'Andrea Cennini, Il libro dell'arte (late 14th/early 15th century)

How to cast medals
If you wish to cast medals, you may cast them in clay or in plaster. Get them dry, and then melt some sulphur; get it cast in these molds, and it will be done. And if you wish to do them just with plaster, mix ground read lead with it; that is, mix the dry powder with the plaster. And make it as stiff as you think best, to suit yourself.
Source: Cennino d'Andrea Cennini, The Craftsman's Handbook. 'Il Libro dell'Arte," trans. Daniel Thompson, Jr. (New York: Dover Publications, 1960), 130.

Vannoccio Biringuccio, Pirotechnia (1540, posthumous print publication)

[82v] I shall now continue by telling you of half reliefs and bas-reliefs of figures, leaves, ornaments or scenes. There is the ordinary way of making their molds, when they are of wax, with clay spread over it. The mould remains complete when the wax is taken out by the fire. If they are things of bronze, marble, or wood, the mold is made by filling in the undercuts, drying them, then greasing the whole thing well, and applying the clay. The pattern is taken out and the fillers returned to their places and fastened in with nails or attached with soft thin clay.

If they are important things well made in wax or soft clay and are less than a half relief they can be moulded in plaster of Paris in such a way as not to lose the first pattern. The wax can be poured in the plaster of Paris to make an exact likeness and the mould made on this. But if they surpass the half relief and you do not have fillers for making the undercuts because they are difficult, or if you cannot make them because the pattern is of soft clay, do without them. For this reason there are some who usually make a paste of hide shreds or parchment scrapings as strong and resistant as possible, made into a well-mixed and clean glue. First, having greased the scene well with oil or pig fat and made a retainer around it of wood or slightly warm clay, they apply this glue and let it sit. When it has set they turn it upside down on a board, together with the scene, and take off the scene by pulling. The impression remains very well formed in this glue, even though it has many undercuts. Now, having greased this well with a small brush, you can cast the plaster of Paris on it. Anyone with discretion would cast it in wax as well, but certainly in plaster of Paris, because it is a better, safer, and harder thing. Following this the plaster mould could also be cleaned well, if you wish, and remoulded in clay, and in this impression you would surely cast in wax and thus have a pattern from which the mould for casting in bronze can be made without spoiling the first one.

But in order to avoid making so many moulds on moulds, some of the same or a stronger glue, if you can have any, is taken and put in with some fine burned painter's plaster of Paris; this is mixed, cast into that impression in the first glue, and allowed to set. Then by turning it upside down the impression of the first mould is taken off and the positive remains; this is covered all over with a brush with liquid clay made of cloth clippings, and the mould is gradually made of the desired thickness inside. Finally, if it does not come out on being turned upside down, it is taken out with a little heat from a fire. Thus, by means of this relief made with glue and plaster of Paris, you have a way of making a mould for casting in bronze, but it is a long and tiresome way. If I should have to make such a work and should wish to use this method, because of the separating surfaces between the moulds seem to me dangerous and weak on account of the heat and moisture of one glue against another, and of the clay against the glue, I would make them all of tin foil, silver, or base gold. For even if it were more expensive, it would seem to me to be a better and safer way.

Source: Vannoccio Biringuccio, The Pirotechnia of Vannoccio Biringuccio. The Classic Sixteenth-Century Treatise on Metals and Metallurgy, trans. and ed. by Cyril Stanley Smith and Martha Teach Gnudi (New York: Dover Publications, 1990), 232-33.

Giorgio Vasari, Le vite de' più eccellenti pittori, scultori e architettori (1568 edition)

From the lives of Gentile da Fabriano and Vittore Pisanello [NB: The information below refers to Pisanello]
Il medesimo Vittore fece in medaglioni di getto infiniti ritratti di prìncipi de’ suoi tempi e d’altri, dai quali poi sono stati fatti molti quadri di ritratti in pittura. E monsignor Giovio in una lettera volgare, che egli scrive al signor duca Cosimo, la quale si legge stampata con molte altre, dice parlando di Vittore Pisano queste parole: Costui fu ancora prestantissimo nell’opera de’ bassi rilievi, stimati difficilissimi dagl’artefici, perché sono il mezzo tra il piano delle pitture e ’l tondo delle statue. E perciò si veggiono di sua mano molte lodate medaglie di gran principi, fatte in forma maiuscola della misura propria di quel riverso che il Guidi mi ha mandato del cavallo armato.

Hugh Plat, The jewell house of art and nature (1594)

From "The Art of molding and casting"

Hugh-Platt_Casting.pdf

[Rough transcription]

1 You must first roast or burne the paister of Paris, before you mixe the same with the reste of the powders, which some men do in this manner. They breake the stones in great gobbets, and then laying some coales in a little stone furnace, such as are solde at more gate; they lay these pieces together upon the coles, and then cover them over with coles, and after kindle the fire at the top, and so let the fame burne downewardes, and with one fire so made they will be sufficiently burnt, then beate them into powder, and searce them as before, but if they breake not easily then they doo burne them longer. Others think it a better way though more longe and troublesome, to beate teh paster in a great iron morter to a fine powder, and then to sette the same in the fire, in a large strong earthen pot, or pipkin, making a good fire under it, and stirring it continually, with a wodden spattle for an houre, or there abouts, and untill you see the spattle leave as it were a visible line, or tracte behind it, after you have stirred the pouder round about there with.

2 Let your powder whereof you make your pop consist of burnt aleblaster, and plaster of Paris both of them finely powdred, & searced, & of y like fine powder of newe earthen pots, some use the powder of bricke instead thereof. To three parts of teh powders of Aleblaster, and plaster first mixed in equall proportion, mingle one parte of the powder of earthen pots or bricke, but many do cast of in wax, only in moldes consisting in alelabster alone, or plaster alone, or both together without any other composition.
there bee some that thinke that shall caste more sharpley if hee doe likewise grinde the aforesaide powders upon a Marble stone after they bee searsed, but if you searse onely, the searse msut bee exceeding fine. Ore. If Gypsum, alumen plumosum, or spawde bee not good to mingle with the rest of the powders. I have seene oftentimes many good patternes of metall, cast off very sharpely in spawde alone, but you must heat the flaskes wel, before you pour in the metals, and you must sprincle the spawd with some moisture, wherin there is some Sal Armoniack, before you doo imprint your patternes, some commend y light and downy substance, finely gathered from the upper most aprt of the old coales.

3 Of the aforesaid powders, you must take a reasonable quantitie at once, putting the same into a stone porrenger, or woodden dish, and put thereunto some cleane water, wherein some dissolve an ounce of Sal Armoniack to every pottle of water, and presently stir it wel togither as before, to make a perfect solution and mixture of the matters aforesaide, this pap must not bee made too stiffe, when you cast off braunches of hearbes or flowers, for then it woulde presse the leaves together. Sometimes temper with warme water, and sometimes with colde, to make the pap drie the faster, for some kind of workes.

4 If you would attaine to a perfection of this pap, you may weight your powders before you put them into your water, and measure the water, which you mingle with your powders, and trying several proportions of water and powder together, you may observe which of them provest best in the moulds, and ever after continue the same.

5 Some doo mingle Aqua vitae, some urine, and some put a small quantity of Sal Armoniack to a great proportion of water, and therewith temper their pap.

6 As you poure in your pap, knock upon the Table with your fist, hard by the cofin, to make the pap settle the better to the bottome, and more close to the pattern.

…

10 Mold many branches of Time, Isop, rosemary, &c, at once. that if some of them should faile, yet one or other might prove wel, for the charge is not great, neither of your moldes, nor yet in the melting of your mettall.

11 When you meane to cast any golde or silver, you must neale the moldes red hot again, & cast presently. But if in pewter or lead, a lesse heate will serve, and osme use no heat at all, but cast the saide mettals in the moulds being cold.

12 You must make a vent with a strawe from the bottome of the mold unto the top, wherby the mettal (finding aire) may run the better, or rather make a double vent from each side of the mold; this strawe must be laid in the cofin, before you pour in the pap, and when the mold is nealed, the straw consumeth to ashes, and the vent appeareth, yet I have seene many patternes cast, without giving any vent at al.

…

24 Some will molde greate, and curious patternes in the crumme of fine manchet wel tempetered into a past, and pressed hard uppon the patterne, and some commend flower, and the fat of bacon dissolved, and strayned.

25 Note also that you must first cast all you curious patternes in yellow wax tempered with the fine powder of smale cole, and wrong thorugh a cloth, and some thinke it best to put in the smale cole powder when the wax beginneth to coole, and then to stir it well that they may incorporate together. But if you wil cast of in red wax, then must you put in some red ocre insteade of smale cole, to color your wax withall. Some comend this composition of wax best fc.2.parts of old yellow wax one part rosen, & a little blacking dissolved, and mingled together, and then streyned through a fine cloth: and when you have once gotten your patternes in wax, then mold those waxen patternes int he aforesaid pasters, alleblaster, and bricke powder, and then burne out the wax as before in flowers, and cleer the moldes, and so cast them into what mettall you please. Also when you have molded any patterne in glew, you may cast it of in Alleblaster if you please.

Piemontese

Ruscelli, Girolamo (accessed on EEBO)
The secretes of the reuerend Maister Alexis of Piemont Containing excellent remedies against diuers diseases, woundes, and other accidentes, with the maner to make distillations, parfumes, consitures, dyinges, colours, fussions, and meltinges. A worke well approued, verye profitable and necessarie for euerye man. Newely corrected and amended, and also somewhat enlarged in certaine places, whiche wanted in the fyrst edition. Translated oute of Frenche into Englyshe, by William Warde. , Prynted at London : By Rouland Hall, for Nycolas England, dwellynge in Pater noster rowe, 1562.

Date: 1562
Bib name / number: STC (2nd ed.) / 296
Physical description: [6], 122, [10] leaves
Copy from: Harvard University. Library (reel 305) and Bodleian Library (reel 1980)

Relevant pages
Ruscelli_Girolamo-The_secretes_of_the_reuerende_Mayster-STC-295-164_05-p118.pdf
Ruscelli_Girolamo-The_secretes_of_the_reuerende_Mayster-STC-295-164_05-p119.pdf
Ruscelli_Girolamo-The_secretes_of_the_reuerende_Mayster-STC-295-164_05-p120.pdf
Ruscelli_Girolamo-The_secretes_of_the_reuerende_Mayster-STC-295-164_05-p123.pdf

Rough transcription

The true and perfyte practyse to caste medalles;

p. 110

Firste of all, you muste have alwayes the earth or sande ready, wherein you wyll fasthy(?) on and fourme youre worke…

so thende that if a manne can not get or make the one, he may evermore have recourse to the other. And understand, that all these that we wyll put here, maye be let a moske(?) eche of them by them selves, or myred one wyth another, or all together, for they are good everye waye. The bountye and perfectyon of eche of these earthes for to caste anye metal in, consp(?)eth in these thynges, that is to wytte: that first and chieflie it be fine and small, and in no wise rough, or full of grommels, to the intent that all thynges maye easely take p(?)pnt. Secondly that they receyve

the mettal well, and that they neyther cleave, breake, chappe, or ware into a cruste. They must also be tempered with a water called Magistra (of the whiche we will speake afterwarde) to the intente that beynge o(?)ye, they may be harder, and holde faster together. Thyrdly, that they may continue, and serve at divers foundinges and melynges, to the intente that whan you wyll caste many metalles, or other thynges all of one forte, ye neede not at every tyme make newe mouldes. Also you muste understande, that for metalles that are softe, as Leade, and Iynne(?), all earth, so it be good, wil suffise: Provided alwayes, that it will be fyne and small, and well tempered with the fayed Magiftra, as I wyll declared hereafter.

"Fyrste earth”

“The second earth or sande”

[ESC notes]
break pots into pieces (from Valentia in Italy or glassmakers’ pots, new or used)
beat/stamp them into a morter

“The thirde earth, or sande”

take the fylying of yron, sande, or yron ooze(?), or the sparke that flye from hoate yron whan it is beaten or els al together: but that it be pure without anye earth or fylth: than put it in an yron panne, or in some other bessel that wyll enure the fyre, sprinklyng it with strong (?)inaiger, and kepynge it on the fyre the space of eyghte houres, after thys temper it agayne in (?)inaiger, and the incense, and heate it in the fyre, braytnge(?) and renewyng it oivers tymes, as the other. And liepe it in leather bagges, or bores well (?)opped.

“The fyft earth, and the moste parfyt”

take mutton bones, but yfyan take those of the heade, they will be better, if not, take of what part so ever it be, and burne them uppon the coales or in som furneis, until they ware very white; tha stampe them, and sifte them. This doen, you shall put the poulnen…

“The syxte earth”

Take Cuttle bones, and burne them in the fyre, until they be very white, and ofe them in all thinges as you oyo(?) the mutton bones, and than kepe it as afoze. Finally; there is also earth made of the ashes...

Biringuccio (324 - 328)

The First Chapter: Various Methods of Making Powders in Which to Cast Bronzes in the Small Art of Casting

The Second Chapter: The Method of Preparing the Salt for Giving the Magistery to the Casting Powders

The Third Chapter: Concerning the Order and Manner of Moulding with Powder in Frames or Wooden Boxes in the Small Art of Casting

The Fourth Chapter: The Method of Making Powders for Casting Every Kind of Metal in Green Sand* adn the Manner of Moulding



ingredients wool cloth cuttings, earth, spent wash ashes horse dung, crushe brick, tripoli, vine ashes tiles, glazed drainpipes calcined tin, straw burned bpaper horse dong, youn g ram's horn ashes

pumice, iron scale, magistery of salt

Cennini (77)

Cennini pg 77 gesso.jpg

Cellini (pg 81, chapter XX)

Cellini 81 casting.jpg

Cellini (pg. 113, Chapter II)

Cellini good clay 113.jpg