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.
Have You Ever Made Homemade Metal Clay Oil Paste?
If so, what oil did you use?
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 Sterling, PMC OneFire Sterling or EZ960, among others.
Homemade oil paste is made with either Sherri Haab PasteMaker, which I find produces the tackiest or stickiest consistency (a very desirable quality when you are joining components with it) and also the strongest joins, 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 MC 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 will focus on making silver clay oil paste with PMC3 or 960 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 with many other metal clay formulas and types, including other silver clays and BRONZclay and COPPRclay, both of which I have used successfully with this process. Be sure to check with the manufacturer to make sure the brand and formula you want to use is compatible with oil additives.
Make Extra-Strong Silver Oil Paste From PMC Sterling or .960 Sterling Silver Lump Clay
- For the strongest silver clay oil paste, mix the slip from PMC Sterling or .960 sterling fresh lump clay straight from the package.
- To join fine, sterling or enriched sterling silver (.960) metal (including fired silver clay), make sure the oil paste is thoroughly dry, then fire in activated carbon at the recommended temperature for the clay used to make 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 join thoroughly, then 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 the metal clay formula you used in the piece or the oil paste.
Sherri Haab PasteMaker—Even Better Than Lavender Oil for Making Metal Clay Oil Paste
I was skeptical about the value of a commercial specialty solution for making homemade metal clay oil paste since lavender oil gave me good results in my homemade silver and bronze clay oil paste. But many years ago, after my friend Wanaree Tanner raved about it, I finally ordered some Sherri Haab PasteMaker to see whether it was appreciably better than the lavender oil I had been using. It quickly became my favorite additive for making homemade metal clay oil paste, and I recommend it highly!
I use the prepared PasteMaker-enhanced slip mostly with greenware (dried, unfired pieces) and find that it holds even delicate pieces together securely. And, of course, it works great to join fired components or to add greenware components to fired components.
How to Make Metal Clay Oil Paste with Sherri Haab PasteMaker Solution
Mix 6 to 10 drops of PasteMaker thoroughly into a pea-sized lump of fresh clay. The amount you add will determine the consistency of the prepared oil paste. Immediately scrape the paste into a small, lidded, airtight container.
Here's how I make oil paste with PasteMaker: I start by cutting off a small piece of fresh clay and scraping it onto a glass disc or sheet. I prefer using a glass surface for preparing my oil paste (or any type of metal clay paste or slip) because it' makes it easy to scrape up the clay and oil mixture efficiently. I add just a few drops of PasteMaker initially, mashing it into the clay thoroughly with a palette knife. Then I add more drops of PasteMaker one drop at a time, blending in each drop with the palette knife very thoroughly, until I get the peanut butter or toothpaste consistency I want. As soon as I have achieved the desired consistency, I scrape the prepared oil paste into one of the small glass jars with tight screw-on lids that I've saved from sample-size or travel-size cosmetics and lip gloss and cleaned thoroughly for this purpose.
How to Use Metal Clay Oil Paste Made with Sherri Haab PasteMaker Solution
The prepared silver paste can be used to join leather-hard, bone-dry or fired silver clay components, including making repairs to fired pieces. The prepared bronze or copper paste can be used to join moist, leather-hard or bone dry bronze or copper clay components.
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 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 before applying them to the skin for aromatherapy or massage.
- Cooking oils or carrier oils do not react the same way with the paste as 100% pure essential oils or tinctures made from pure essential oils, alcohol, and water.
- In fact, small amounts of carrier or cooking oils can be mixed into lump clay to make it flexible, which also makes the clay stick to itself less readily—the opposite of the desired effect.
Don't Love Lavender Oil but Want to Use an Essential Oil for Your Oil Paste?
Try One of These Other Plant-Based Essential Oils Instead
Some 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 artists who can't tolerate the smell of other essential oils find that peppermint essential oil doesn't give them a headache.
- Rosemary essential oil has a pleasant, herbal scent that is more muted than that of many other essential oils.
- Pink grapefruit essential oil has a fresh, clean, citrus scent that you might prefer for your homemade silver oil paste.
Alternatively, try this sampler with a variety of different plant-based 100% pure essential oils to find ones that are effective and also smell pleasant to you and don't cause you headaches.
I strongly recommend buying your 100% pure essential oil in dark amber glass bottles. A regular or European style dropper cap is ideal, but you also can use a separate eye dropper to measure out your oil.
"How to Make Lavender Paste for Use With PMC" — an article originally published in the Summer 2007 issue of Fusion, the Journal of the PMC Guild — has been archived on Rio Grande's website. The article not only describes a method for making homemade lavender oil paste but also shows the results of strength tests.
Questions & Answers
© 2010 Margaret Schindel