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Token-Making-art - 6/14/15
"Introduction to Pewter Casting" by Baron Christopher MacConing, OL.
This article was submitted to me by the author for inclusion in this set of files, called Stefan's Florilegium.
These files are available on the Internet at: http://www.florilegium.org
Copyright to the contents of this file remains with the author or translator.
While the author will likely give permission for this work to be reprinted in SCA type publications, please check with the author first or check for any permissions granted at the end of this file.
Mark S. Harris...AKA:..Stefan li Rous
stefan at florilegium.org
You can find more by this author on his website at: www.acunningplot.com
Introduction to Pewter Casting
by Baron Christopher MacConing, OL
MKA Christopher Cunning
TABLE OF CONTENTS
Written: March 10, 2008
Last Updated: September 02, 2013 (New Notes and Pictures)
Casting at its heart is the concept of taking an item or design and rendering it in metal form. The number, detail, and metal desired for use will often dictate your casting technique, but for the purposes of this article, we will be focusing on casting multiple copies of a design in pewter using stone moulds. The techniques covered here can be applied to everything from buttons to baronial or Kingdom awards to highly detailed pilgrim tokens, but it is important to establish a foundation of good practices for design, preparation, carving, casting, and clean up.
Often at SCA events, tokens are often given at the door to show payment of some fashion. After the event however, their fate is left to chance. Some are kept as mementos of an event so that a person will always remember that day. Others are discarded, having served their purpose. Some are even recycled so the material can be used again. In the case of the crafter, they often place their mould on the shelf where it may or may not ever be used again. In other words, they are single use items.
I hate single use items. For me, if an item is worth owning, I should be able to use it a lot, and for a lot of different applications. This goes for my clothes, tools in my work area, my kitchen equipment, pretty much my entire house. If I do have a single use item, it has to be really important, such as a fire extinguisher.
When I was approached to cast my first pewter event tokens for the Windmasters' Hill Pas d'Armes, I decided that I wanted to design a token that would both fulfill the requirements of the customer as well as be usable beyond that. After discussing this with Mistress Clare de Crecy (LSCA) and Master Eldrid Tremayne (LSCA), they showed me the medieval use of bezants, small metal ornaments used to adorn clothing. With the concept of a combination site token/bezant in mind, I selected a heraldic acorn from the Fox-Davis's A Complete Guide to Heraldry as my design. It would fit with the theme suggested for the event, and afterwards could be used as a bezant to accent clothing, either for myself or others.
The Pas token was a complete success on both fronts. The autocrat, staff, and attendees were very pleased with the design, and requests were made for more tokens so that they could be used as bezants by persons attending the event. From then on, unless the customer's needs prevent me, I have attempted to design my event tokens not only to fulfill their original purpose, but so that they can be used later to adorn clothing.
When beginning your design process, it is important to get the design established both in your mind and on paper. Think about how you would like it to look. If there is person requesting an item, discuss it in detail with them, or better yet, get them to bring you a drawing or picture of what they would like. Determine a size, and dimension for the item. Most importantly, make sure you feel comfortable with the design. I cannot count the number of projects I have seen go in the bin because a caster took on a project they may not have been ready for, or worse rushed, and became frustrated and gave up. Remember, anything can be done with enough time, patience, and practice.
For my designs, if the patron does not have a specific pattern in mind I will often consult the Fox-Davis Guide to Heraldry, various other books, and of course the internet, to locate a design that will meet the requirements of the patron. You may even be able to access historical examples or reproductions that you can study in detail, not only to reproduce for your customer, but to gain insight into how the original is made. Finally, my favorite source for designs is objects found in real life
An excellent example is the Order of the Coral Branch. For this one I wanted an organic design for the coral. So, I used this as an excuse to go diving (my other expensive hobby) and study some of the coral off the shores of NC.
Art… Imitating Real Life.
As shown in Pilgrim Souvenirs and Secular Badges, token and bezant moulds were often carved in stone, allowing for mass numbers of castings or stamps, and as casting projects for the SCA often requires numbers in the hundreds I prefer stone as well. For these projects, many select soapstone as it is readily available and historically accurate. However, these often can contain larger grains of stone and occlusions, larger bits of material (ex. talc), that can come out in chunks during carving. For this reason I prefer African wunder stone to act as the mould. It is similar to soapstone in hardness, but is more solid, has very little if any occlusion, and is of a finer grain, all of which will provide a smoother surface in the final carving.
In any case, when selecting your stone for casting, look for fine grain stone with little to no occlusion, and in sizes that you can either easily cut to your needs, or better yet, in pieces that are already cut to a useable size. Often, stone suppliers will have scrap stone in sizes you can use, and may even sell them to you at discount.
WARNING: Sanding, carving, or cutting wunder stone will create a very fine dust that if inhaled can over time lead to silicosis of the lungs. Wunder stone should ALWAYS be worked in a well ventilated area, preferably outside, with a filtered face mask. Afterwards, clean up any dust with a damp cloth or similar item.
I begin by selecting or cutting two pieces of stone that will be of a size appropriate to contain the token to be cast. There should be suitable thickness in the stone to prevent cracking during the carving process, as well as to prevent accidentally carving through. I also prefer a slightly thicker stone as it allows me to cast for longer periods of time before the stone becomes too hot to handle, even with heavy gloves. From there the inner sides which the design will be carved into are chosen based upon their flatness and how well they match up. The sides of the stone are marked (I, II, III, IV) to ensure the same placement of the stones against each other every time. The stone is now ready for sanding.
14th Cen. Bezant
The inner mating sides are sanded by placing the surface to be sanded downwards onto a section of 150 grit sanding paper (ones with adhesive backing work best for this process) which has been taped or attached to a hard smooth surface such as polished marble or glass (available for cheap at your local hardware store). The fingers are placed on the edges of the stone and pressed down to apply slight pressure so that the stone will move across the paper without skipping or rocking. The stone is then repeatedly moved by hand in a crosswise pattern working up and down, then left and right on the sanding paper. Some persons prefer to move the stone circularly; however this may increase the chance of creating an uneven surface. Move from 150 grit to 180 grit and finally 220 grit sandpaper to improve the fit of the stones against each other. Check the stones periodically to determine if the sides meet flush. If the two halves are placed together and light is visible between them, continue sanding. Finally, rub the two sides against each other with a bit of saliva (yes, I mean spit) between them to smooth the surface even further and complete the mating process.
When the stone sides are flush, they should match each other with no light showing between them, and very smooth, almost polished carving surface. If the stones are completely flush with each other, rubbing them against each other will allow the stones to "stick" together due to the vacuum created between the stones. When you can pick up both stones by lifting the top one, and they remain together for an extended period of time (5 sec or longer), your stones are ready.
The first consideration in drawing is placement of the token in the mould for optimal flow. Examine the design and orient it on the face of the stone so that any points or small extensions in the design (ex. Fleur-de-lis) are downwards, ensuring that the material will flow into them while hottest. Often designs are carved upside down to ensure more detail as well as hide the sprue connection in the base of the token.
After a few practice runs on paper, sketch the design onto the stone with a mechanical pencil. This will allow the design to be more visible under direct light. If you have problems drawing onto stone (or in general), take a copy of the graphic and, using a small pin, punch a series of holes into any lines for the drawing. Tape the drawing onto the stone in the correct position and run pencil or marker along the lines with the holes. The holes will leave a series of marks on the stone, and you can complete the graphic on the stone by connecting the dots!
Lightly etch the outline of the design into the surface with a pointed carving tool, similar to the head of a needle or nail, to provide a more visible working outline. Once the design is well outlined, gradually carve out the stone using Xacto knives and/or carving tools to achieve the proper depth and shape. The depth and shape should be checked by pressing clay or Sculpy II into the mould and then examining the impression. Remember to work lightly and patiently, and not to rush. Once the stone is removed, it can't be put back! Take breaks to rest your muscles and eyes. Rushing or working too long will cause you to dig too deeply, or worse, leave a mark you may not be able to get out.
My Carving Station: knives, carvers, dremel bits, and a face mask
When the desired shape and depth and is achieved, the cavity of the design should be smoothed out to achieve a flat, smooth surface. Check often with the sculpy, and use a magnifying glass to examine your progress.
Details can be added using some of the following suggested tools:
Other tools that might be helpful are wax carving tools, clay or stone sculpting tools, and dental picks.
Keep an extra stone as a work stone in order to practice any detail work before attempting on the mould, ESPECIALLY LETTERS! These will have to be done backwards, so practice several times and practice your penmanship!
Details should be checked often using clay or Sculpy II to ensure that the details look appropriate.
Carving details and checking with Sculpy
Once the detail work is completed, final cleanup work is performed. Using a magnifying glass and good light, examine the carving carefully and ,with a pick or Xacto knife, smooth out any scratches or track marks made by tools to ensure a smooth finish. On the edges and detail work, remove any overhangs in the carving which might cause the pewter to grab the mould and damage it when a token are removed, as well as adding a slight outward slant to any lines or edges to facilitate easier token removal.
Since the token is to be hung from a string or jump ring, a small ring should be carved at the top of the token. This is easily done using the base of the shaft of a dremel tool head inserted upside down into the Xacto tool handle. Since the shaft of the head is circular, it will carve a perfect rounded ring. A very small, rounded, carving head will also work very well.
After ensuring that the surface appears clean and smooth at all points, lightly scrub the surface of the carving with a extra fine grit paste (tooth paste, not gel) and a brush (an old toothbrush) and water. Rinse the mould thoroughly and allow it to dry. NEVER pour metal into a wet mould! Doing so can result in splattering of metal, usually right at you, and damage to the mould.
On the opposing stone face of the mould, you will need a grid of venting lines to allow air to escape as the metal flows in from your sprue, as well as to possibly provide some additional strength to your token. Draw out a grid pattern of lines and then lightly carve a series of lines following the pattern using a pointed head or other small carving tool.
In order to ensure that the mould remains matched and in place, you may wish to add a set of key locks, metal pegs that will "lock" the stones into the same place. Mark a spot on each of the corners of the back and front stones, allowing enough space to ensure that the stone corners will still be strong. If you match your stones to each other, as I do, where both stones are the same size and shape, this can be easily accomplished by placing a pencil or other writing device in your hand and setting the point on your preferred depth. Place your middle finger along the side of the stone as a guide, and then run the pencil along the edge of the stone. Repeat on the other stone and you should be matched. Mark the sides of the vented back stone as well. On the back stone, drill down on the vented face and then from the side to form an "L" shaped tunnel. Drill down slightly on the face of the front stone with a larger bit to a cavity for the pegs. Clamp the stones together and then pour metal into the "L" shaped holes, pouring repeatedly to ensure it fills, and then allowing it to cool before moving on to the next corner. When completed, you should have a key and peg system that will keep your mould in position.
Finally, a sprue from the top of the mould to the token is drawn out and carved, tapering in size to the base of the carving. The sprue should be wide enough to allow a sufficient quantity of metal to flow freely into the carving and fill out all details, while being small enough to remove from the token once carved. In the case of the more convoluted items, a small branch can be added from the main sprue to other points on your mould to allow easier flow.
Lines for venting and holes for pegs.
The number of vent lines and size of the sprue can be adjusted after test pours to assure optimal effect in regards to the flow of the metal.
Perform a test pour on your mould and using the sprue created, use it to map out the position of the sprue on the opposing stone and then carve to out a conical sprue which will allow the pewter to flow into the mould in a larger amount.
WARNING: When working with any molten metal, heavy gloves, long sleeved shirts, jeans, and safety glasses are a must! It is also highly encouraged that you wear close toed, leather shoes and an apron of durable material.
For casting material, I use American lead-free casting pewter (92% tin, 7.5% antimony, .5% Copper). If your work is extremely detailed, you may wish to consider using pewter with a higher tin content (ex. Aqua-Clean) or pure tin. These are more expensive, but will flow more easily to fill out detail work.
Casting Station: Metal ingots, moulds, melting furnace
and ladle, protective gloves
Heat the melting pot to the desired temperature (between 500-600 degrees F) and using ladle, pour the molten pewter repeatedly over your mould to heat it up and allow better pouring. After the mould is sufficiently warm, clamp the two sides of the mould together, or hold them together with your fingers inside well insulated gloves, and pour the pewter into the sprue hole. After allowing the mould to cool, split open the halves of the mould and remove your token from the mould (I use a pair of needle nose pliers to grab the sprue). As the token and the mould are both hot, you should never use an unprotected hand to handle the token or the mould. Re-assemble your mould and repeat.
1. Clamp the mould firmly shut 2. Pour the molten Pewter into the mould
3. Cool the metal, unclamp and open 4. Perfect pour
5. Repeat as necessary
It may take several tries before the token fills completely, as the stone will need time to heat up properly.
If the mould does not fill completely, or has imperfections after several tries, consider the following solutions:
Once your tokens are casting correctly, continue the process until your desired number is achieved.
Remove the sprue using cutters as well as any flash material (I use nail trimmers for this) to ensure a proper shape and smooth edges. Filing with hobby files, small metal-working files, grinders, and/or polishers may also be needed. However, if your mould is tight and the metal is at a good temperature, very little flash material should appear.
Cast and cleaned tokens (Silver Nautilus, Sea Dragon, Unicornate Seahorse, Atlantian CoA)
While the use of stone carved moulds in casting has been traced throughout recorded history, the use of pewter pilgrim style tokens is most heavily documented from the 12th century onwards as persons traveling to religious sites or places of importance would wish a remembrance of the journey. It is upon this concept that, in my mind, we base our event tokens on, and as we journey throughout the country to Events we return home with a small memento of our travels.
On the whole the differences in construction for my pewter tokens from period are mostly in the tools and materials:
While the moulds in period are often documented as being carved from materials such as wood, soapstone, or cuttlebone, I use wunder stone as it provides a more workable material with less occlusion.
In period, the materials used for casting tokens were often mixtures of lead and lesser amounts of tin, with copper and antimony showing up later periods as the process evolved. However, due to the safety concerns involving lead, modern lead-free pewter uses mostly tin with small amounts of copper and antimony.
Mould crafters often use the small carving chisels and implements tools, hand crafted to their purpose, or simply available. I use more modern, and common, fabricated tools such as hand mounted dremel bits, steel carving tools, and Xacto knives. While I am sure they are not as precise as the fine, detailed carving tools of their modern brethren, they are more available and less expensive
For process of heating of the pewter, rather than use a fire based heating method in which the heat may be inconsistent, I use an electric melting crucible which provides a cleaner, safer environment for casting, and more control over the temperature of the metal.
In both period work and my work, hand tools are used to carve the mould, and the moulds are hand poured from molten pewter into the stone mould. In this overall perspective, the casting techniques are equivalent.
Stone casting, especially tokens, is often the foundation set of skills you gain on your path. With these you can move on to metals such as brass, bronze, iron, and even precious metals, as well as more exciting techniques, including:
· Multi-part Moulds
· Sand Casting
· Slosh Casting
· Lost Wax
As always, credit goes to my original teachers, Master Eldrid Tremayne, LSCA, and Mistress Clare de Crecy, LSCA, for getting me started on this path. Without their knowledge and patience, I would be lost.
Thanks to Duchess Kyneburh Boithuile (LSCA, OP) for her insights on projects and techniques.
Special thanks go to my wife, Lady Ysane de la Selle, for all of her help and encouragement.
A Complete Guide to Heraldry, A.C. Fox-Davies. Copyright 1978: Bonanza Printing.
Medieval Pilgrim and Secular Badges, Brian Spencer. Copyright 1998: TSO
Fashion in the Age of the Black Prince, S.M Newton. Copyright 1980: Boydell Press
Fashion in Medieval France, S. Heller. Copyright 2007: Cambridge Press
Textiles and Clothing 1150-1450, E. Crowfoot, F. Pritchard, and K. Staniland. Copyright: 2001 Boydell Press
The Compleat Sculptor
90 Vandam St.
New York, NY 10013
Notes: Make sure that you order reasonably thick stone (.7-1.0"), preferably in small blocks that you can work or cut. Ordering large stones to cut up may cause you difficulty.
Rio Grande Jewelry Supply
Notes: Good for smaller orders of metal. You will pay a little more though. You will also need to set up an account for on-line ordering
Ney Metals & Alloys
272 Georgia Ave.
Brooklyn, NY 11207-4000
Notes: Good for large orders of metal (25 lbs +). By ordering in large amounts, you can get metals at discounted prices. Get some friends together for an order.
Notes: Casting equipment is under the Bullet Casting section. Look at melting furnaces, ingot moulds and lead dippers. Avoid gravity pour pots, as pewter is lighter than lead and can flow through the gravity spout.
This document is the intellectual property of Christopher Cunning. It may be reproduced, cited, and/or referenced for educational purposed only and should be credited when used as a source material. Reproduction for personal gain or unethical academic-style practices (plagiarism, et. al) should be reported to the Kingdom A&S Officer.
If this article is reprinted in a publication, please place a notice in the publication that you found this article in the Florilegium. I would also appreciate an email to myself, so that I can track which articles are being reprinted. Thanks. -Stefan.