How to Make Metal Clay Oil Paste
Oil Paste Makes Extra-Strong Joins in Fired or Unfired Metal Clay
Slip is one of the basic forms of metal clay. It's made by thinning lump clay with water to form a smooth, thick liquid or paste, depending on the application for which you are using it. Slip is not essential for joining metal clay components together, and it creates a weaker joint than dry-building, using fresh clay straight from the package, or syringe clay, all of which contain more metal and less water than slip does. For the same reason, in most situations, thicker slip (sometimes referred to as paste) will create a stronger joint than thinner slip.
Adding 100% pure essential oil, an essential oil tincture (a diluted form made from pure essential oil, water, and alcohol) or Sherri Haab PasteMaker to most (but not all) brands of metal clay slip changes its consistency and holding power considerably. Many artists consider silver oil paste the preferred material for joining fired pieces of silver clay together or for joining milled silver (wire, settings, findings, sheet, etc.) to sintered metal clay,
This article provides helpful information about making your own homemade oil paste.
Homemade Metal Clay Oil Paste
Homemade metal clay oil paste can be used to join metal components that are compatible with the type, firing method and schedule of the clay used to make the oil paste; to create very strong joins between pieces of metal clay greenware (dried but not fired clay). In the case of silver oil paste, it can be used to attach dried clay or fired silver clay to silver metal.
Because of the flexibility in firing schedules, you can use homemade oil paste to attach sterling silver earring posts, bezel cups, or other sterling silver findings to silver metal (including fired silver metal clay) and fire as low as 1300ºF for 30-35 minutes. Note that attachments made with silver clay oil paste and fired at this lower firing schedule to prevent the sterling silver from degrading will not be as strong as soldered joins. For extra-strong homemade oil paste, prepare it from a compatible sterling or enriched sterling silver clay, such as PMC 925 Sterling, PMC 950 Sterling, and EZ960, among others.
Homemade oil paste is made with either Sherri Haab PasteMaker, which produces a paste with an extremely sticky consistency (a very desirable quality when you are joining components with it) that results in an extremely strong bond, or with a 100% pure essential oil. Lavender oil is the most commonly used choice, but another plant-based essential oil (but not a carrier oil) may be substituted for those people who don't like its smell. Some artists use a tincture of a plant-based pure essential oil; I prefer having more control over the proportions of oil to water in my oil paste.
As with regular slip, you can add metal clay dust or scraps and a little water (along with more essential oil) to replenish your container as you use it up.
Oil paste can be mixed up whenever you need it, in whatever quantity you need, so you never have to worry about running out. If you don't use it often enough to want to keep a container of it on hand, you can mix up only as much as you need, when you need it.
This article focuses on making silver clay oil paste with PMC3 or enriched sterling clay, since that is what I have used most often for this purpose. However, the same method may be used to create oil paste from many other metal clay brands, types, and formulas, including other silver and base metal clays. I recommend checking with the manufacturer to make sure the brand and formula you want to use is compatible with essential oil additives.
Make Extra-Strong Silver Oil Paste From Sterling or Enriched (950 or 960) Sterling Silver Clay
For the strongest silver clay oil paste, prepare the slip with PMC 925 Sterling, PMC 950 Sterling sterling, or .960 sterling made by mixing equal amounts (by weight) of fresh .999 fine silver and .925 sterling clay, straight from the package.
- To join fine, sterling or enriched sterling silver metal (including fired silver clay), make sure the oil paste is thoroughly dry, then fire the piece in activated carbon at the temperature recommended for the clay you used for the oil paste. Hold at that temperature for 1 to 2 hours.
- To join PMC3 greenware to any of the above metals using this extra-strong oil paste, dry the attachment area thoroughly, pre-fire the piece on an open kiln shelf at 1000°F for 30 minutes, and then fire in activated carbon at the hottest and longest firing schedule for whichever metal clay formula you used to make the oil paste.
Sherri Haab PasteMaker Solution: Even Better Than Lavender Oil
The first time I Sherri Haab's PasteMaker solution on a supplier's website, I was skeptical about the need for an alternative to the lavender oil metal clay artists had been using successfully for years to make homemade oil paste. But after Wanaree Tanner, an amazing artist, raved about it when we finally met in person at the last PMC Conference in 2012, I knew it must be special. It quickly replaced essential oils as my preferred additive for this purpose.
I use the prepared PasteMaker-enhanced slip mostly with greenware (dried, unfired pieces), and have found that it holds even delicate pieces together securely. It also works superbly for its primary intended purpose, joining fired or unfired components to metal, or joining previously fired pieces.
Preparing and Using Metal Clay Oil Paste With PasteMaker
I recommend making only as much as you anticipate using up within a few weeks or a month. Whenever I have opened even a tightly sealed container of leftover oil paste that has been stored for a long time, I have found a dried-up, rock-hard lump that is firmly attached to inside of the jar. Unfortunately, unlike slip mixed from clay and water, oil paste cannot easily be reconstituted and restored to its prior smooth, creamy consistency.
My Preferred Method For Making Oil Paste
- Cut off a small piece of fresh clay, straight from the package, and place it on a smooth glass work surface. You can use a smooth, glazed ceramic tile, if you prefer.
- Mash a few drops of PasteMaker into the clay thoroughly with a small, thin, stainless steel palette knife.
- Add more solution one drop at a time, mashing each drop into the clay with the palette knife very thoroughly before adding more, until the paste is a smooth, creamy, uniform consistency, similar to peanut butter or toothpaste. For a pea-sized amount of fresh clay, I usually add about 6–10 drops total to get the consistency I want.
- Scrape the mixture into a very small, airtight, shallow container made of a non-reactive material, such as glass, acrylic, or plastic. The smaller and shorter the container, the better: the less air space there is between the inside of the lid and surface of the paste or slip, the longer the mixture will retain its moisture and original consistency.
Tiny, airtight, cosmetic sample jars with a 3–7 ml or gram capacity (approximately 3/5 to 1.4 teaspoons) are perfect for keeping small amounts of oil paste (or slip) from drying out in between uses.
How to Use Metal Clay Oil Paste Made with PasteMaker
The prepared paste can be used to join leather-hard, bone-dry or fired silver clay components, including making repairs to fired pieces.
Alternative Plant-Based Essential Oils to Try If You Can't Stand the Smell of Lavender
A few metal clay artists who dislike the strong aroma of undiluted lavender oil have experimented successfully with other plant-based 100% pure essential oils, such as peppermint, grapefruit and rosewood oil. Some who can't tolerate the smell of other essential oils have said that peppermint oil is one of the few that won't trigger headaches for them. Rosemary oil has a pleasant, herbal, more subtle scent, while pink grapefruit oil has a fresh, clean, citrus scent.
If you are looking for an alternative to lavender oil, (including the three I mentioned) to help you find at least one whose smell doesn't bother you or give you a headache. You might even find one whose scent you enjoy! I suggest getting this sampler set containing 12 different plant-based, 100% pure essential oils
I recommend buying 100% pure essential oil in amber, cobalt or green glass bottles, which help protect against degradation of the oil from exposure to UV light. Look for ones with European-style dropper caps that minimize exposure to air and give you better control when you want to dispense a single drop at a time.
How to Make Homemade Oil Paste from PMC Silver Metal Clay
Making homemade PMC oil paste is fast and easy. Here's how:
- Start with a small jar of plain PMC3 silver metal clay slip or mix up a similar amount of slip from PMC3, PMC Sterling or 960 sterling lump clay.
- Mix tincture of lavender (essential lavender oil diluted with alcohol and sometimes water) or 100% pure essential lavender oil (or another 100% pure essential plant oil; see "Don't Love Lavender?", below) and water into some plain silver clay slip, a few drops at a time, stirring with a palette knife until it is smooth and creamy. If you are using a tincture of lavender, start by mixing in 5–10 drops, or if you are using a 100% pure essential oil, start by mixing in 3–5 drops of essential oil and then adding 1-2 drops of water.
Note: When preparing the paste with 100% pure essential oil (rather than a tincture), some artists also add a small amount of isopropyl alcohol along with the water. The alcohol evaporates as it dries, but some metal clay artists find that it makes the consistency of the paste a bit creamier. Experiment and judge for yourself.
- Continue adding drops of tincture (or 100% pure essential oil and water, and alcohol if you're using it), adjusting the proportions a drop or two at a time, until you have a very thick, very creamy slip that smells strongly of whatever essential oil you are using.
- Cover the mixture tightly and allow it to sit overnight.
- Stir the homemade oil paste well before using.
There is no precise recipe for making homemade oil paste, and of course, the amounts of the oil, alcohol, and water you add will depend to a large extent on how much plain slip you start with. As a frame of reference, when I'm making homemade oil paste from a new, 15-gram jar of commercial PMC3 slip, I usually add about 25-35 drops of lavender tincture, or about 15–25 drops of pure essential lavender oil, about 5-10 drops of alcohol, and just enough water to get the consistency I want.
When purchasing 100% pure essential oils or tinctures, make sure you know whether the bottle comes with a standard bulb-type dropper cap or a European "dropper orifice" ( i.e., the opening of the bottle acts like a built-in dropper). If the bottle doesn't come with a dropper, you'll need to buy either a dropper cap (make sure it fits the bottle!) to replace the original cap, an eyedropper, or a pipette that you can use as a dropper.
You may want to work in a well-ventilated area if you are sensitive to the smell/fumes from the essential oil you are using. If you are extremely sensitive to the smell, you might want to store your prepared lavender oil paste in a room other than your studio.
- When making homemade oil paste from any PMC clay formula, be sure to use either a 100% pure essential oil or a pure essential oil tincture.
- Do not use an essential oil blend that contains cooking or carrier oils, such as jojoba, sweet almond, grapeseed, olive, avocado, sesame, evening primrose, sunflower, canola, emu, castor, or nut oils. (Carrier oils are used to dilute essential oils that will be applied to the skin, such as for aromatherapy or massage.)
Cooking oils and carrier oils don't react the same way with the clay as either 100% pure essential oils or tinctures made from pure essential oils, alcohol, and water. In fact, they make the clay stick to itself less readily, which is the opposite of the desired effect.
The article "How to Make Lavender Paste for Use With PMC," originally published in the Summer 2007 issue of Fusion, the Journal of the PMC Guild, and subsequently updated and archived on Rio Grande's website, not only describes one method for making homemade lavender oil paste but also shows how it performed in strength tests.
Questions & Answers
Can the PasteMaker solution be mixed with the ground, dried silver clay to make slip?
I would recommend reconstituting the powdered silver clay and then taking a pea-sized amount to mix with the PasteMaker solution to make oil paste.Helpful 4
© 2010 Margaret Schindel