Thursday, 26 February 2009

Making Lavender Paste & repairing fired PMC & art clay silver

Updating and Repairing Silver Clay Pieces.
Sometimes I like to revisit an earlier piece or update it for a new look...with unfired clay this is easy (use slip) but when pieces have been fired you need to either:
1) Make a mechanical bond, like drilling a hole and attaching the new piece by squeezing it on (this then forms it's own little rivet when fired).
2) Or attaching the fired pieces with a special type of paste.
There is something called Art Clay Oil Paste which makes a very strong bond for connecting 2 previously fired pieces
It costs about £15 though so I'm going to show you how to make your own version!
Making Lavender Oil Paste
Lavender oil can be added to silver clay paste to make your own oil paste. Gradually add pure lavender oil drops to a thick PMC or ACS paste mixture (15-30 drops). Stir with a plastic spatula or wooden stick until it binds together. Let it sit overnight to assure complete absorption before using. You can make Lavender Oil with PMC plus, PMC3 and all Art Clay products.

Attaching the fired pieces
When you want a strong bond on fired pieces Oil paste is a must!
Here's how I do it:
1) Roughen the surface of the parts where they're to meet (or
put them back in the kiln again for 10 mins) that gives them a rougher texture to adhere to.
2) Attach the 2 pieces with a good gob of paste & for extra "stick" add slip to seal in the edges
3) Let air dry slowly or overnight
4) Try not to wiggle the pieces too much as (until they're fired) the bond still isn't as strong as when you use slip on unfired pieces.

Fire at the hottest temp your clay and inclusions can stand preferably for at least 2 hrs.
(I use 850 degrees)

Extra Info:Here's a useful article by the PMC guild which shows some strength tests using lavender oil paste.
Art Magazine has a making lavender paste video (you have to join but I think it's free).

Happy Making
Nic xx

Wednesday, 25 February 2009

Storing Unused PMC & Art Clay Silver Clay

Storing Unused Clay
I know that in the early days it seems almost impossible that you'll have any left over clay from those "tiny little packets", but just in case you do here's a few suggestions for keeping your clay from drying out....
NB - If you use different types of clay with different shrinkage or drying rates e.g. Original PMC / PMC+ or ACS650 / ACS650 slow dry it's best to have a seperate labelled container for each

For short term storage -
Use the outer foil pack that your clay came in..
Make sure your clay is moist (if not dampen it) then wrap in cling film before putting back into the ziplock packet.
Wet a piece of kitchen towel & put into packet with the clingfilm wrapped clay.
Ziplock the top shut. (This has kept clay good for days for me & if you keep check the moisture level daily there's no reason it couldn't be longer).

For Regular Storage -
A home made option is to get a small airtight container (little lidded pots)and put a piece of wet sponge in the bottom (dense make up sponge type).
The moist wrapped clay then goes into the pot and you keep the sponge moist.
This way you can have multiple pieces.

Longer Term Storage -
If you want a good pre-made solution or have larger quantities of clay to store regularly then an American site has something called Clay Vaults and Clay Keepers. They are "zip lock" plastic containers with hydrated water crystals inside & they're very good.

Nic xx

Tuesday, 24 February 2009

3 Kiln Comparison

There are lots of Kilns on the Market suitable for firing Precious Metal Clay. Here is a rundown on three of the most popular ~ the Kitiki Mini-Kiln, the Paragon SC-Series, and the Ultra-Lite kiln.

The Kitiki Mini-kiln is a good choice where kiln loads are likely to be small, or where space is an issue. It can be used for general low-budget small-scale work such as Art Clay, PMC, dichroic glass, enamelling, and jewellery.
If you are looking to buy a kiln for the first time, the Kitiki Mini-Kiln is a good choice for home, school, craft workshop, jewellery studio, or class. Besides being compact and easy to move, it uses a regular mains socket (no need for expensive re-wiring), it stays cool on the outside, it's controllable, it heats and cools quickly, and it's inexpensive to run.
Important Points
The Mini-Kiln has a Controller, not a Programmer, so there will be some limitations in available firing schedules. e.g. If the target temperature is low, and if the heating rate is set to full, the actual temperature will overshoot before the thermocouple and programmer can regulate it. If the target temperature is high, the overshoot will usually be negligible. While these variations don't affect Art Clay and PMC, they might affect glass, particularly dichroic glass.

The Mini-Kiln has a smaller firing chamber than larger kilns such as the SC2, so you can't stack it full of shelves with loads of pieces of jewellery: just four or five average things on the floor of the firing chamber, on a ceramic-fibre cloth or shelf. (i.e. Not big enough for large Bronze clay containers)

The Mini-Kiln heats to a lower top temperature – the top temperature of the Mini-Kiln is 1000°C, while the top temperature for the SC-2 is 1095°C. (This should not be an issue for PMC, Art Clay, dichroic glass or enamelling).

The Mini-Kiln door opens 90° so, unless the kiln has cooled completely, you should use long tongs in order not to burn your hand taking pieces out. The SC-2 door opens 180°.

Having said that it does have it's benefits too! It's more portable than an SC2 and cheaper too approx prices are currently £300-£350. :)

The Paragon SC series kilns The Paragon SC2 is a good first-kiln, popular with silver clay artists, particularly those also making jewellery with beads, dichroics, enamels, glass, and silver.
It's ideal for a studio running jewellery courses: it's compact and easy to move, it can use a regular mains socket, it stays cool on the outside, it's fully programmable, it heats and cools quickly, and it's inexpensive to run.

The Paragon SC series kilns come in two versions, as the SC-2 and the 50mm taller SC-3. Each version is made in the following four types: Basic, W with viewing window (shown), B with bead-annealing door, and BW with both door and window.
Firing CharacteristicsAll small, fast-heating, ceramic-fibre kilns, such as those in the SC series, with heating elements in both sides and the back, have firing characteristics you need to be aware of:
The actual temperature can overshoot before the thermocouple and programmer can regulate it: particularly if the heating rate is set to full. Set to a high temperature, the overshoot will usually be negligible.
Work placed at the back of the kiln will be slightly hotter than work at the front. Work near the sides of the kiln will be slightly hotter than work in the middle. If you're using several shelves, work on the top shelf will be slightly cooler.
The glass window in the SC2W, SC2BW, SC3W, and SC3BW, will modify the front-to-back temperature difference slightly. Also, at continual high temperatures, the window glass might discolour: but it's easy and cheap to replace. (You can also use the fibre plug when not enamelling etc to avoid this)

Apart from its internal size, the only minor limitation is that, although 1095°C is hot enough for low-fire ceramics, it's not hot enough for normal ceramics, porcelain, pottery, and stoneware: they need a 1260°C or 1290°C kiln.

My UK version SC-2 kiln has a sheathed thermocouple which helps prevent the possible corrosion, and eventual failure, of the bi-metallic tip: usually caused by pollutants produced whilst heating some types of glass.
The electronic display prompts for heating rate, target temperature, and hold time, making it easy to set up and re-use accurate drying, heating, holding, and cooling sequences.
Approx cost: £500-£600 (dependant on specification)

The UltraLite Kiln, is perfect for drying and firing your PMC, for enamelling, glass fusing, making jewellery, and keum-boo work. Please note that the Ultra Lite is not programmable - it's an 845°C, 250W, low-cost, compact, round kiln, with a lift-off lid

The UltraLite Kiln heats and cools quickly, but costs very little to run. It's ideal for small-scale work in your home, school, craft workshop, or jewellery studio, or at an arts centre running jewellery courses.
The UltraLite Kiln weighs just 1kg, so is easy to take to craft fairs, demonstrations, and exhibitions. If you already have a kiln, you can use an Ultra Lite for drying metal clays, firing single pieces, or quick tests. If you run courses, use several so that more experienced students can optimise their time, rather than wait for the slowest to catch up.

Firing Characteristics
The UltraLite is a small, fast-heating, ceramic-fibre kiln, with one embedded heating element in the bottom. Max temp is about 845°C. Putting the lid off-centre will effectively vent the kiln and reduce the temperature but, unless you use a pyrometer, you won't know what that temperature is.
It's ideal for firing Art Clay and PMC using the firing disc insert, and for keum-boo work using the red brass tops. At 845°C you can't over-fire silver clays as silver doesn't melt until about 962°C. You can work with dichroic glasses, enamels, and fused glass, but will need to experiment.
Keep a firing log: the material you used, the arrangement of pieces on the shelf, the firing cycle, and the end result. The log is useful if you're learning about colour, materials, temperature, and firing time, and a skilled artist will use the firing characteristics to advantage for different effects.

The only minor limitation is that, although 845°C is hot enough for silver metal-clays, it's not hot enough for gold metal-clays, ceramics, porcelain, pottery, and stoneware: they need a 1260°C or 1290°C kiln.

Approx cost: £180-£210 (dependant on specification, e.g. keum-boo plate & lid)

There are lots and lots of kilns out there, these are just a few of them (I have the SC2 with a viewing window) ~ if you have a different model and have found it fabulous and great value then please let us know about it in the comments box! :)

Applying Gold Overlay Paste to Silver Clay

Applying Gold Overlay Paste
The best method I've used was to fire the silver then carefully remove the cool silver without touching the area you are adding gold to (finger oils will affect gold adhesion).
Add the gold while the silver is still in it's white stage and then torch fire it on.
Dry naturally, ***do not use a griddle or hotplate to dry
Apply multiple thin coats of gold***must be thin coats***
2 coats will yield a very subtle gold application, 3 or 4 will be much more visable
***must dry in between coats as directed above

When Torch firing Torch evenly until the orange glow is present then time the firing for 3-7 minutes (do not overheat or the gold will be absorbed into the surface of the silver...just a light orange glow...not red). I then Finish & Polish the whole pendant by hand, burnishing the gold areas particularly gently.


Monday, 23 February 2009

Drying Methods for Art Clay Silver & PMC

Today I've been asked about drying the pieces you've made before firing.
So here are some things you can do to dry your silverclay.

Air Drying ~ The easiest way to dry pieces is leave them in a warm room for 24 hours and voila all finished! (Slow air drying is also best for Bronze & Gold clays and repairs filled with paste).
Mug Warmer/Hotplate ~ For those of us in a rush, or teaching a class, then a mug warmer or other form of hotplate is great too (AGA & Range oven owners will be grinning now). With these you'll need to keep an eye on the pieces and turn them over every now and again so they dry evenly (or the piece can warp/curl).
Hairdryer ~ Haven't got a hotplate? Then a hairdryer will speed up the drying process, just be carefull not to blow your freshly made piece accross the room! To avoid this put the piece on a mesh and then dry with the hairdryer. (Great for drying syringe work)
Food Dehydrator ~ If you've cash to splash a food dehydrator will dry lots of pieces quickly, probably best that you then don't use it for preparing your home made muesli in!
Oven Drying ~ If you're making lots of pieces then you can oven dry them approx 20mins at 200 degress should do the trick! (I dry them on a clay tile)

Nic xx

Sunday, 22 February 2009

Carving Text onto PMC & Silver Clay

Adding Handwritten Text into Silver Clay pieces
The easiest way is using a sharp solid point (like the end of a burnishing tool).
You need to wait until the clay is dry (or it kicks up messy edges). Sand & prep the area where the name will go then write your lettering using a soft pencil.
Lightly scrape the name onto the clay, support the work well as you do this (so you don't break it). Repeatedly scrape over the same lines building up depth. You'll find a kiddies paintbrush helps remove the dust, which you can keep for making slip. Fire the piece and polish it as normal.

Tip: To make the text stand out even more, apply a liver of sulphur patina and then re-polish the piece.

Making a Photographic Background

I thought this quick explanation of how to make your own graduated background in Photoshop (or similar) might come in useful. :)
It'll save you £££'s against buying one!

You need:
1 x Sheet of Matt Photographic paper (ideally A4)
1 x Ink-jet or Laser-jet printer
1 x Photo programme (e.g. Photoshop)

Instructions:1) Set your paper size to A4 (210 × 297 mm)
2) Use the Colour selector to select the Colours you'd like your gradient to be (e.g. Black & White)
3) Select the gradient tool (on photoshop it's behind the paint bucket tool)
4) Fill a selection by clicking and dragging the pointer across the canvas or selection. The larger the drag the more gradual the gradient will be. All of the control of the tool lies in the dragging of the pointer. Pressing and holding the shift key will create perfectly aligned gradients.
Have a play with whatever programme you're using their are normally a few options for different gradient styles.....
When you're happy print it out onto the photo paper and voilĂ  you have your own professional looking photo background! Here's an example of something I took using mine (I selected the darker area of the gradient but by using an A4 sheet you can also select a lighter gradient)

My pics aren't up to studio standard but with the help of a cheapo ebay light tent and some good lighting you can get some great results....

As a comparison here's the same jewellery item on a white background and a graduated background

Nic xxx

Saturday, 21 February 2009

Hob Firing PMC and Art Clay Silver

Ideally, SilverClay needs firing for a set time at a set temperature.
However, with practice, you can fire small pieces on a kitchen gas hob. This is best for pieces no bigger than a 50p piece and if you dont have a gas hob you could try a portable camping stove.

Lay the mesh on the hob and light the gas. As it heats up you'll notice cherry red areas these will be heating between 650-800 degrees (suitable for silver clay). Turn the gas off and, after the mesh has cooled, lay your dried clay on one of the red spots. Cover the piece with a mesh "box" for firing safety and relight the gas.

Fire your piece for 6-10 minutes, making sure that it's still in a red spot. Let it cool before you touch it, or the mesh. N.B If you don't get any red spots then your hobs flame may be too far from the mesh & the metal wont be strong enough if you try to fire this way... If you have a camping stove try that :)

Happy Heating x

Torch Firing PMC & Art Clay Silver

Torch Firing Process
(With thanks to Tim McCreight & his article in Studio PMC)
Allow the work to dry overnight or drive off moisture with a hairdryer, or in a slow oven. Make sure it's completely dry or the work can explode! Torch firing is not recommended for large items and you need good ventilation as you'll be close to the clay when the binder is burning off.
2. Place the work on a soldering block or fire brick, which is in turn set on either a fireproof surface or something you don’t mind being singed (like a piece of plywood). If you are working on the kitchen counter and the piece rolls off the block you don’t want to scar the countertop.
3. Light the torch and hold it so the flame is nearly vertical with the tip of the cone about 3/4" away from the work. Within a minute, the piece will be enveloped in a soft flame as the binder burns away. The flame will soon go out by itself. Within another minute, the piece will start to glow red. Continue heating until this becomes a bright and luminous color. At this point, glance at a clock.
4. Hold this color as uniformly as possible for about 5-7minutes. When the time is up, turn off the torch and allow the piece to cool. If you're not sure it's fully cooled use tongs or tweezers to pick it up and (providing it's not stone set) quench it in water.

A suggestion - Melt some Silverclay on Purpose
Most standard handheld torches are rated at 2000F so they can melt silver clay, in an effort to avoid this it's worth doing this experiment so you know what to look for.

Pull off a pea-sized bit of your chosen silver clay (PMC or ACS), split it in half, and roll out two small rods. Follow the instructions above with one added step. Concentrate the flame on one of the rods in an effort to melt it. You’ll see a bright mercury-like skin form on the piece and the red color will become even brighter. The edges will start to curl and the metal will be drawn up into a ball.
Make a mental note of what you saw. This way you’ll know the signs of melting, and you can withdraw the torch in time before damaging a piece you care about. To complete the experiment, allow the other rod to cool and test it by bending, filing, burnishing, and polishing. This will confirm that, sure enough, torch firing really works!

Friday, 20 February 2009

PMC Tool List

I've been asked a few questions on PMC mainly during my courses, so I thought I'd start a Blog to put lots of useful advice all in one place :)

PMC Suggested TOOLS - minimum needs, in order of use
A roller - used for rolling out the clay
A rolling surface - Non-stick as possible e.g. a glass board or polished tile
Spacers or playing cards - for getting the depth of the clay even
Cutting blade, scalpel - For getting straight edges and making your shapes.
A small lidded pot - to put filings & tiny offcuts into so you can save them for making silver clay paste or slip
Various grades of sanding pads - or get a 4 way nail filing block and strip the sides off.

For Hob firing, stainless steel mesh with protection net.
Torch firing - Handheld torch and a firing brick (asbestos substitute not a household brick )
Kiln - If you can get access to a kiln then use it, the metal is normally denser and the results more consistant.
Stainless steel or brass brush - for brushing off the white post firing and leaving you lovely silver.
Silver polish & Cloth - for getting the final buffed up shine.

Some Optional Extras:
For ring making - A sliding ring guage, A wooden ring mandrel, and ring papers (to stop clay sticking to the mandrel).
For Better finishes - A small set of metal files for neatening edges quicker than sanding them down.
Long Tweezers - For holding / moving the pieces when firing
Liver of Sulpher - For antiquing or bringing out fine detail
Burnishers & ultra fine sanding pads - Post firing for a REAL shine!
Cutters & Shapers - Using pre-shaped cutters e.g. hearts will same time and give you more consistant shapes
Tiny drill bits - you can twist them in your fingers to drill through the unfired clay & make jump ring holes & hanging points.
Texture Mats/plates - Roll the clay out on these and you'll have fabulous patterns straight away!
Letter Stamp Set - For stamping words into unfired (rubber stamps) or fired clay (metal stamps).
Feel free to add any suggestions & comments (I'll add them to the list)
Nic xx

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