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Create beautiful fused art glass jewelry in a microwave kiln - in minutes!
Fuseworks Microwave Kiln Kit $129
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Recommendations for Assembling a Microwave Kiln Jewelry Kit
|Click here for User's Manual How-to-Use Information||Click here for User's Manual How-to-Use Instructions||Click here for User's Manual How-to-Use Information||Bullseye Glass, Dichroic Glass, Art Clay Silver||Glass Molds, Porcelain Blanks, Shelf Paper, Shelf Primer, Bails|
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Small, Medium & Large Microwave Kilns
Caution: Several sellers who advertise "Large" are actually selling "Medium" sizes. Also, some sellers advertise "Small" sizes as "Medium". CHECK THE MEASUREMENTS!
Hello! After about a twenty-year absence of microwave kilns in the USA, I am the person who got sales going again in the USA about a three years ago. Competitors bought them, copied them (my instructions, photos, and header tags too!) - and are selling them. I also was first person to cut Bullseye Thin-Fire paper into little squares and sell packages of miniature shelf papers! Lots of people are doing that now! Microwave kilns are really popular now!
Please note that I do not claim to be an expert glass fuser! My glass experience is mainly in the stained glass area, but I discovered microwave kilns and thought they were the neatest things on the planet! My "expertise" here is in attempting to consolidate and compile. So, if you are an expert in fusing and you see inaccuracies here, please forgive! And I would appreciate your emailing a correction, too! (Confession: As a glass artist, I was afraid to buy and use a traditional kiln - but I wanted to fuse glass. Then I obtained a microwave kiln from a foreign source and that got me started. I have NEVER used the small traditional kiln that I later purchased!)
Microwave kilns provide a fast, relatively inexpensive way for someone to find out if glass fusing is a hobby that they might enjoy. They also are fast, convenient tools or accessory tools for experienced fusers to use alongside their traditional kilns.
* * *
my original design and my original photo
Microwave oven kilns allow you to fuse glass jewelry, process silver metal clay or fire ceramics in an ordinary microwave oven. I have directed you to this page to help you learn more them OR because you have already purchased one and need to know how to use it. If you appreciate the many hours I spent researching this material and posting it on this website, please purchase your microwave kiln from me.
Welcome to my website, www.microwave-kiln.com. Click here to purchase a Microwave kiln. I also sell on various other e-commerce sites, too.
The pendant shown below was made of Bullseye fusible glass and dichroic glass; it was fully fused in five minutes in a small microwave kiln. (This was the second fusing project that I had ever done! The bail was affixed after firing. The second picture is a size comparison between small and medium Microkilns (the pendants measure one square inch).
|SMALL MICROWAVE KILNS - APPROXIMATE SIZES: Firing chamber is 2-3/4" in diameter by 1- 3/4" high (Exterior dimensions are 4.5" diameter by 3.375" high). This is a perfect size for making pendants and small jewelry.|
|MEDIUM MICROWAVE KILNS - APPROXIMATE SIZES: Firing chamber is 4-1/2" in diameter by 1-3/4" high. Outside measurements are approximately 6- 1/2" x 3- 1/4" high (which is 16.5 cm x 8.25 cm) This is a perfect size for a pair of earrings or larger projects.|
|LARGE MICROKILN MICROWAVE KILN - APPROXIMATE SIZES: Firing chamber is 6-1/4" in diameter by 2-3/8" high. Outside measurements are approximately 9" in diameter and 4-3/4" high. (Firing chamber 15.87 cm x 6 cm; Outside 22.8 cm x 12.7 cm) A 4"x4" tile will fit in this one! (Most of the "large" models which are advertised are actually MEDIUM size! Very few sellers offer large size (Example: "largest sold in USA" does not state a size and "Large Microkiln kit" (the kit is large, not the microwave kiln). DON'T BE FOOLED! CHECK THE MEASUREMENTS!.|
|NOTICE: Some microwave kiln brands don't state a size, but you can bet they're small. Check the measurements! Fuseworks - (which I also sell!) comes in a little kit has a small size microwave kiln - but their sellers NEVER say that it's a small size! Small microwave kilns are great if that's what you want - they heat faster and are excellent for fusing single small pieces BUT check the measurements so you will know what you're getting! There are some small internet sellers who very boldly misrepresent the size of the Fuseworks microwave kiln kits that they sell, calling it a "medium". It is not a medium as compared to the other "mediums" in the industry! And I have found several sellers who misrepresent the sizes of other brands! So, be an informed buyer and CHECK THE MEASUREMENTS!|
INTRODUCTION & SAFETY
IT IS IMPORTANT THAT YOU READ ALL OF THIS MATERIAL BEFORE USING YOUR MICROWAVE KILN! Please do not lend your microwave kiln to a relative or friend unless they have read every word here, too!
Art Clay Silver is associated with microwave kilns. Here is their manual. Read it carefully as this information is their official "word" on the subject of safety requirements and it addresses how to use Art Clay Silver. (Art Clay Silver is available here). Please read this before using your microwave kiln! And please note #3 where it says, "Heating time would take longer if the wattage of the microwave is less than 500 watts...." This also means that if your microwave's wattage is MORE than 500 watts that your beginning firing times should be less than the times shown. And another caution is to allow your microwave oven to cool at least 20 minutes between firings.
Mr. Jack Ludwig of American Beauty Mirrors in Chicago, Illinois, sent a very detailed instruction booklet which accompanied a Micro-Kiln that he purchased 15 years ago. Access this archived, "official," very comprehensive and useful treasure here. Thank you, Jack! This important caution is included in that material, "Always clean the inside of your microwave oven after using MicroKiln and before using your microwave oven for food preparation." A separate, dedicated microwave oven is recommended. This material includes information about firing GLASS and CERAMICS.
Ceramic Arts Daily published an excellent article on using microwave kilns for ceramics work. Read the article here.
* * *
The following information has been compiled from various sources and contains my comments.
The microwave kiln is safe to use in any microwave oven but firing times will vary depending on wattage. (Another website recommends avoiding microwave ovens exceeding 1,100 watts. I tend to agree with this because glass can shatter if fired too fast). Another brand specifies 800-1000watt microwaves and NEVER an Emerson brand. (I assume they did a lot of testing before they excluded Emersons.) Do not fire longer than recommended firing times. Allow 20 to 30 minutes between firings to allow the microwave oven to cool. The small microwave that I have uses 950 watts and it generally takes 5 minutes to fully fuse a pendant, but it may take only 4 minutes or less in a 1200 watt microwave oven. Overfiring lessens the life of a microwave kiln. A MEDIUM MODEL WILL TAKE LONGER TO FUSE GLASS. Let your project cool 20 minutes and then refire for any additional needed time. If nothing happened, you did not fire long enough!
Paragon's MagicFuse manual states that some older microwave ovens cannot successfully fire a microwave kiln, and that a newer microwave oven should be used. It also says that some microwave ovens heat the glass unevenly and that you should try a different microwave oven or fuse only one piece at a time.
Many microwave kiln sites recommend using a microwave oven with an 800 watt rating.
Do not fire for 8 minutes, then add 2 more, then 1 more. Instead, remove kiln and let it cool down after each firing. Then you can add more time. The microwave oven needs to cool down inside from the heat the kiln generates. Overheating your microwave oven can cause it to blow a fuse.
This kiln can be used in conjunction with a traditional kiln for pre-fusing small pieces of glass, firing precious metal clays, or in the area of ceramics, or it can be used as your sole kiln for firing small pieces. Regardless which way it is used, there are real savings in time and electricity! And microwave kilns are FUN!
Did you know that Vicki Payne once did a video about fusing glass jewelry in a microwave kiln?
Microwave kilns are sold by craft retailers throughout Europe and Australia and I usually see them advertised in conjunction with Art Clay Silver. But when I searched American sources, I found ACS usually was associated with Paragon Kilns. I did searches and found that Paragon makes a Quick Fire 6 kiln from ceramic fiber - as microwave kilns are.
A PMC Hot Pot also has a ceramic fiber shell.
MicroKiln, Paragon Quick Fire 6, and PMC Hot Pot Kiln
Paragon now manufactures MagicFuse, its own brand of microwave kiln. See links at the top of this page for more information.
In a popular internet forum someone expressed fear that heat will "geyser" out of the hole in the top and the microwave oven will catch on fire. In order to avoid even the slightest possibility of this happening, you should immediately take the microwave kiln out of the microwave oven after firing, place it on a heat resistant surface and away from flammable materials. Do not place it under upper kitchen cabinets, etc. If the microwave kiln were left in the microwave to cool repeatedly, eventually this excess heat coming out of the hole in the top would make the plastic ceiling of the microwave quite brittle and it would probably start to crack. My distributor said that he has personally done hundreds of firings over a short period (3 days) while demonstrating the microwave kilns at trade shows and while the microwave oven did get quite hot from all the firings there was no damage to it or the table it was sitting on.
In the user's manual that Mr. Jack Ludwig contributed, it is stated, "It is important that there is at least 2 inches between the top of the microwave kiln and the ceiling of the inside of your microwave oven."
Very, very rarely a small flame might appear at the top hole where there was no other possible source of flames except the shelf paper. The flame might extend 1/2" out of the hole while it is firing in the microwave oven. We do not consider this a fire hazard as long as there is sufficient clearance to the inside roof of the microwave. In order to prevent this from happening, cut shelf paper size to match your project so that there will be enough coverage but not excess. Paper which is cut to size and covered would have less chance of igniting. AGAIN, DO NOT LEAVE A MICROWAVE KILN UNATTENDED WHILE FIRING!
If you were to put a microwave kiln that had just finished firing underneath a flammable surface with less than a couple of inches of clearance you might be able to set it on fire depending a great deal on the specific conditions. (I have NEVER heard of this actually happening!) You should not put a hot microwave kiln in proximity to any surface that is flammable or that could melt. Melting a kitchen counter by putting a hot microwave kiln directly on it (which we also warn against doing) is a much more likely problem than starting a fire from the flue hole gases. Also we have had the flue hole gases tested when using our Multipens on glass or ceramic and they are non-toxic and quite safe for use in a microwave also used for food.
|This summary was recently contributed in a PMC
forum: (I am not a member of that group).
Based upon the material contributed by Jack Ludwig, the word "graphite" should be used where Deborah used the word "granite."
Reluctantly, I must say that not all brands are constructed equally well. Based upon my personal experience and feedback from my customers, I personally recommend a Microkiln or a Magicfuse.
In addition to the microwave kiln, you will need to purchase a microwave oven, glass, Bullseye Thin-Fire shelf paper or fiber paper. Shelf paper may cause a little burning smell as the binder in the paper burns off, and is only good for one firing. Use a new piece of shelf paper each time and place shiny-side-up when using. For more information about Bullseye paper, click HERE.
You will also need basic stained glass cutting and breaking tools. A glass cutter and running pliers might be all you need if you work with small pieces of glass. A small, inexpensive glass grinder often comes in handy, too.
These supplies are available at any stained glass or ceramics retail store. All are available at www.microwave-kiln.com. You may use kiln wash but allow it to dry thoroughly before using your microwave kiln. We now recommend a combination of kiln wash and shelf paper as the best coverage, but this is a recommendation only. I do not use kiln wash. If you wish to use kiln wash, apply several thin coats on the base, allow to dry thoroughly. Re-apply kiln wash every 3-5 firings or as needed.
You need a pair of inexpensive gloves (garden gloves are fine) which will be used every time you move the microwave kiln from the microwave oven or remove the top. I like knit ones best because they are a bit thicker.
And you will need a heat-resistant surface such as heat resistant brick, kiln shelf, fiber brick or large ceramic tile on which to set your kiln after removing it from the microwave. Otherwise a hot kiln could cause a fire or burn to the surface.
An increasing number of sources recommend that you always position 3 - 1/2" ceramic posts under the kiln inside the microwave oven. The posts prevent the kiln from overheating the bottom of the microwave. (I personally have never done this).
It is not a toy and is not to be used by children. IT IS A KILN! Please do not allow small children in the same room when you are firing! Use at your own risk and follow all recommended and common-sense safety precautions! Sellers are not responsible for accidents or injuries caused by hot kilns and your using one purchased from this seller acknowledges that you use it at your own risk! And please don't let your cat rub against it!
Before using your microwave kiln, think about "what if" I dropped my hot microwave kiln, what would I need to have immediately available to pick my hot project up with? A pair of metal tongs? Then always have metal tongs readily available while you fire. A metal dust pan and a metal implement such as an egg turner would serve the same purpose. A ceramic tile floor and a carpeted floor would require very different remedies. Think of other scenarios which are based upon the area where you will be working. And keep a box of baking soda handy, too!
One seller recommends putting a ceramic fiber blanket on the floor of the microwave oven if the it does not have a turntable. As the outside of the microwave kiln does not get dangerously hot this is optional as long as you remove the microwave kiln from the oven immediately after firing has finished.
Another seller recommends removing the spinner from the microwave oven before firing. When one of my customers asked why, the answer was to prevent the project from moving around. So that recommendation is not a safety issue. That seller also recommends using ONLY a microwave oven with a metal interior and it must be 1200 watts. As microwave ovens fitting either one of those two criteria just recently started being manufactured, that recommendation is optional. (Microwave kilns have been in use 20+ years). I personally recommend that a spinner be used to ensure even heating as I have personally seen unrepairable damage done to a microwave kiln where hot spots were the only possible cause of damage. (It produced melted holes in the interior and scorching in spots on the outside). It is a rare occurrence, but it does happen).
Do not put any material in the microwave kiln that has not been recommended. Among those things that are not recommended are high temperature wire and iridized stained glass (based on my personal experiences), and gold PMC (precious metal clay).
Please remember that a traditional kiln is composed of fireproofed materials and a microwave oven is made of materials that can burn under certain conditions SO don't try to burn off wax or cork clay or wood clay or any other flammable material in a microwave oven kiln! And don't use nail polish to glue your glass together!!!!!! WAX WILL SET YOUR HOUSE ON FIRE.
Also, protect your Bullseye Thin-Fire Shelf Paper from drifting aerosol can contents such as silicone, spray glue, cooking oil, insect repellents or killers, etc. Do not allow shelf paper to become contaminated with flammable residues.
Before you use your kiln for an actual project, you should place the empty microwave kiln into the microwave oven and fire for three minutes. Let cool for about 20 minutes and you're ready to do your first project. (NOTE: There is a distinct smell which is noticed during an empty prefiring; however, I have never seen in writing nor read anywhere that this is harmful in any way.
I have seen "third hand" reference articles which imply that there are fumes, but these articles seem to address ceramic glazes only. (Please correct me if I am wrong: I am not a ceramics artist). I am not sure if this is an issue only with non-water based products for not, but I suspect that is the case. I have no knowledge that fumes are an issue with glass.
Hold the microkiln with both hands when moving from microwave to heat-resistant tile.
My personal observation is that microwave kilns are suitable for one-of-a-kind projects. For unknown reasons, it is fairly difficult to obtain identical matched-pair results from project to project.
OK! Let's have some FUN!
Check out my dichroic glass and fusible glass supplies here!
Click here to view Sharon Griffin's very detailed Tutorial of how to make various pendants.
Firing times will vary depending on the WATTAGE OF YOUR MICROWAVE OVEN and on the SIZE OF YOUR PROJECT and on the MELTING POINT OF THE GLASS. It will also depend upon whether you TACK FUSE or FULLY FUSE. This explains why there are so many different timetables! Also, some start timing when the hole in the top begins to turn orange - and others don't even mention it!
This is an impossible attempt to consolidate the many timetables that I have seen. EACH MANUFACTURER INCLUDES SPECIFIC RECOMMENDED TIMETABLES FOR THEIR PRODUCTS. But do keep in mind that all microwave kilns are made and work basically the same way! Suggested firing times:
|Microwave Kiln Size||700 watts||800 watts||900 watts||1000 watts||1200 watts|
|Small (2-1/2" platform)||4.8 - 7.5 minutes||2.5 - 4.0 minutes|
|Medium (4-1/2" platform)||8 -10.5 minutes||6.5 -7.7 minutes||5 minutes||4 minutes|
It is necessary to prefire a microwave kiln before using it. Place an empty microwave in the microwave oven and fire until you see an orange glow in the peep hole. Turn the microwave oven off, remove the microwave kiln and let it cool thoroughly before using it for your first project. A small microwave kiln will take less time to fire than a larger one.
You can satisfactorily use stained glass scraps to create jewelry as long as you use only one color OR two or more glasses that have the same coefficient (this requires testing for compatibility). Based upon my personal testing experiences, do not use iridized stained glass! (Bullseye ThinFire paper and iridized glass are incompatible. Dichroic glass is fine). Fusible glass is recommended. There are two major classes of fusible glasses: COE 90 and COE 96. Do not fuse them together! They are not compatible! Your jewelry will eventually crack if you do.
Do not attempt to fire glass trinkets or objects that you did not originally make. There is no way you can know what materials went into that object (painted surface, glued surface, acrylic on the surface, etc.) and firing an unknown material could be very dangerous!
Cut your glass and clean it. Use a dry (non-oiling) glass cutter for cutting glass which will go into a microwave kiln. Traces of oil may catch on fire! Alcohol is great for cleaning, but be sure to dry thoroughly before putting into the microwave. In order to prevent leaving fingerprints on the glass, use tweezers to design and arrange glass.
Any glued projects must be BONE DRY before firing or you WILL damage your kiln! Use only white glue such as Elmer's glue. Note: One microwave kiln manufacturer recommends that you do not use glue as it can discolor dichroic glass.
The shelf paper should be big enough to allow a good margin around your glass piece. The glass piece should be small enough to allow the shelf paper to have a good margin around it. Place glass in the center of it, put the top on and very carefully place it in the microwave oven. Careful placement is necessary to prevent your project from moving around inside the kiln. Do not slam the microwave oven door: close it gently. Gluing pieces together with white glue helps, but the glue must be bone dry before firing. Wet glue creates steam, and steam can damage the black granular lining in the top.
It has been suggested that you will have more control over firing glass if you preheat the kiln with the glass inside on defrost for two minutes before you do a full fuse. I have also seen directions where projects were fired the entire time at 50% power (meaning the microwave oven runs at 100% power but it is turned on only half of the time). Of course, firing times are longer. Firing at half power helps prevent glass from shattering, too.
Another source suggests prefiring 10 to 12 minutes at 40% or 50% power and then continuing with a regular firing schedule to achieve a full fuse. This method helps prevent shattering.
Because the microkiln absorbs radiant heat, the outer edges of your glass will melt faster than the center.
I have read that different brands of glass melt at different temperatures, too. Wasser melts before Spectrum, Spectrum melts before Bullseye, and Bullseye melts before Wissmach. Your results might be most satisfactory if you use one brand of fusible glass. (Note: Fuseworks starter kits contain 90 COE glass but it is not compatible with other 90 COE glasses due to lower melting point and thinness).
Generally, the maximum depth of an unfired, layered glass pendant should be about 1/8 ". More or less depth may change the size and depth of the piece. A project of two layers of thin glass will reach the desired "look" before a project made with two layers thicker glass. Make necessary adjustments to your firing schedule based upon the sizes of your materials.
Do not stack glass higher than the equivalent of one double roll piece (1/8") plus one thin roll piece (1/16") OR three thin roll pieces (3/8"). If you do, puddling may result and glass may stick to the base and sides of the microwave kiln, fusing the top and bottom together.
One microwave kiln manufacturer states that the maximum size of glass fired should be 2" square, and the maximum thickness is 2 layers of 1/8" or 4 layers of 1/16". Two layers of 1/8" x 1" x 1-1/2" is a good average size. Larger or thicker projects may break from heat shock due to the very fast firing rate. For pieces larger than 1" or for more than 2 layers, pre-heat the glass at 50% power for 5 minutes.
Ordinary fusible glass melts around 1425F. Dichroic glass melts around 1650F.
When using black solid or pattern dichroic, place a piece of clear glass slightly larger than the base glass on top to protect the pattern/color.
|1.||Place shelf paper on base of kiln.|
|2.||Place glass in the center of the paper|
|3.||Place kiln in the center of the microwave.|
|4.||Fire until the hole on the lid becomes bright orange. Turn the microwave off.|
|5.||Reset microwave and fire for 3 minutes.*THIS IS A GOOD BEGINNING POINT FOR MY 950 WATT MICROWAVE OVEN, BUT EVERY MICROWAVE OVEN/microwave kiln COMBINATION IS DIFFERENT.|
|6.||Remove from the microwave (with gloves) then allow the unopened kiln to anneal the glass. It takes about 20-30 minutes to anneal.|
|7.||Remove the top. If additional firing is needed, refire no more than three minutes plus 30 seconds. Repeat procedure adding 30 more seconds if more firing is still needed.|
|8.||Remove the kiln from the microwave and set on fireproof surface. Allow the closed container to cool at least 20 - 30 minutes before opening the top.|
Once you have determined how long your project takes, you can put it in and let it fire for the total time. But you will only know that through testing YOUR microwave kiln and YOUR microwave oven.
Molten glass can "crawl". If it should crawl off the shelf paper wait until it cools before attempting to remove it. Molten glass can damage the sides and base of the microwave kiln, so leave enough clearance between your project and these surfaces. Repair kits and replacement bases are available if needed.
What causes sharp edges on the project? Dragging is usually caused by over firing a project that is resting on fiber paper. As the glass contracts and draws in on itself, the paper resists. Sharp edges are the result. You can reshape the piece with your grinder and fire polish in the kiln.
What causes shelf paper to stick to the project? Most likely it is caused by overfiring; the glass begins to "crawl" and pull on the shelf paper. My observation is that it most often occurs when a piece of Bullseye shelf paper has been reused and the project was overfired. You can try to remove stubborn patches with cleaning products used to remove hard chemical residue. You can grind traces off and then fire polish in the kiln. A second theory is that the piece was not bone dry.
One manufacturer recommends five minutes as the recommended minimum firing time. and suggests that you use a reduced power setting on your microwave if it fires in less time than 5 minutes. This will lengthen the firing time to give you finer control.
Another microwave kiln manufacturer recommends a somewhat different firing procedure. The advantage to this procedure is that the microwave is set on medium power, which certainly must be beneficial to the life of your kiln, but the firing time is a little longer. This method is certainly worth testing.
The estimated firing time for an 800 watt microwave oven on medium power is around 6-8 minutes for the small kiln. From there, start experimenting with short times until you see the orange light. If the piece does not fuse satisfactorily, you can fire it for a longer time.
If the oven's power is less than 500w or if you don't see the orange light coming out through the peephole after the established time, fire the piece for a longer time, heating one minute at time, until you get desired result.
This same brand of microwave kiln actually has a microwave kiln kit which contains finished sterling silver bezels which you fill with small pieces of glass and the entire thing is placed inside of the microwave kiln and then into the microwave oven. But, when I used my own piece of sterling silver wire and placed it between two pieces of glass and fired at FULL power, the glass shattered and the microwave oven "buzzed". So, I don't recommend doing this unless you fire at medium power.
Alee Soderman's "Cut Cook & Create" book which was published in 1989 states: "The glass shatters while fusing. This is called thermal shock and results from heating or cooling your glass too quickly. Preheat your projects on the low or defrost cycle before cooking them on high. You may have to adjust your cooking time or use medium power if your microwave oven is more than 700 watts."
I am developing a list of general tips for glass fusing glass jewelry. You can see them here: Jewelry Tips.
USING GLASS MOLDS MADE FROM PLASTER OF PARISAvailable here. Small jewelry molds which fit into a MEDIUM size or equivalent microwave kiln. They will not fit into a small one! A Medium microwave kiln has a FIRING CHAMBER BASE that is 4-1/2" in diameter by 1-3/4" high. Coat with kiln wash prior to use.
The manufacturer says: "The secret with firing these in the MicroKilns is to slow down the firing and watch the progress inside the kiln. Start with 2 minutes at 20% power then go to 2 minutes at 40% and then 2 at 60% power. Slightly lift the lid while still inside the Microwave and check the progress. Then go 1 minute at 100% and check again. If not complete step up in only 30 second increments because from here on up the frit matures very rapidly. If I think it is close but needs just a little more I'll even do 15 seconds at 100% to take it up slowly towards the end. If you follow these suggestions they fire just fine. So does the small slumping S curve mold as well as the other small molds for the Microkilns."
PRECIOUS METAL CLAY (PMC), ART CLAY SILVER, AND OTHER METALS
Art Clay Silver supplies are available here.
Firing times will depend on the wattage of your microwave oven.
Regarding the "Art Clay Silver" document (above): PLEASE NOTE UNDER #3 WHERE IT SAYS, "HEATING TIME WOULD TAKE LONGER IF THE WATTAGE OF THE MICROWAVE IS LESS THAN 500 WATTS...." This also means that if your microwave's wattage is more than 500 watts that your beginning firing times should be less than the times shown in the chart below.
The inside of the microwave kiln reaches very high temperatures up to 1652 F. Notice the melting point of these metals: (Glass melts around 1425 F).
|Copper||1357 F. You can experiment with what you can do with fusible copper sheets such as sandwich between pieces of glass. This could make a mess and ruin your kiln in a hurry!|
|Brass||1652 F. I sandwiched a brass letter between layers of glass just to find out what would happen.|
|Silver (not PMC)**||1763.2 F. Because of this, one source recommended refiring silver clay no more than a second time at 3 minutes.|
|Gold||1947.52 F. Do not fire gold metal clay in your microwave kiln. But I have successfully used a Ferro Gold Rush Ceramic Pen.|
THE FOLLOWING INSTRUCTIONS ARE FOR SILVER CLAY:
Prefiring test: To avoid melting from over firing, do a test firing with 1 gram of flattened, DRIED clay. Draw a line around the outside of your unfired piece, then fire. If the contraction is 8 to 10%, you successfully fired the piece. If art clay melts, shorten the time. If it crumbles, add more time. PMC will shrink about 10%. If you drop it from a height of about 2" above a table and you hear a metal sound, it has been successfully fired. If not, fire again with less time.
If you have never worked with precious metal clay or silver clay, PMC3 might be your best choice. PMC3 has minimal shrinkage and fires at a very low temperature which is very good for your kiln. You can also use certain stones and enamels with PMC3. PMC+ requires a much higher firing temperature and longer firing times. NOTE: I do not recommend putting stones in a microwave kiln as I have never tested them.
PMC3 is best suited for glass applications due to its lower firing temperatures. It is recommended for rings, charms, and pendants. It fires in 10 minutes at 1290 F or 30 minutes at 1110 F** in a traditional kiln. I decided to work with PMC3 because of the lower firing temperatures, which means shorter firing times. The firing process leaves a metal that is less dense than conventional sheet or wire. This means that a piece of jewelry made of PMC is lighter than the same piece made via traditional fabrication; therefore, PMC is not recommended for applications such as findings.
Art Clay Silver 650 is a low-fire product similar to PMC3.
I personally have not yet tested Art Clay Silver to determine what the differences are, if any. Using microwave kilns require EXPERIMENTING!!! But I would recommend that you use whatever formula requires the lowest firing temperature.
Fashion your piece using your fingers and tools, let the project thoroughly dry, fire your piece, and finish by sanding and polishing. (Your piece must be completely dry or it will be deformed. It will also damage your microwave kiln!)
When firing a 3 dimensional piece, support it with a soft ceramic fiber blanket to prevent collapsing under its own weight.
What is the clay volume limit for firing a 3 dimensional piece? Less than 30 grams (which is 1.05 oz). Microwave kilns are not recommended for hollow pieces.
Size Limitation: Small microwave kiln: less than 4 cm (1 1/2""). Do not fire anything larger than this or it will melt.
The size/weight of your project has everything to do with the firing times. Most instructions say to watch for the orange light to appear, turn the microwave off and immediately refire to desired firing time (Use the table below).
Approximate firing time for Art Clay Silver in small microwave kiln:*****
3 grams (which is .1058 oz)
1 to 1.5 minutes
3 -10 grams (which is .1058 oz - .3527 oz.) 1.5 - 2 minutes
10 to 30 grams (which is .3527 oz - 1.0582 oz) 1.5 - 2.5 minutes
rope shape or thin piece 1 min to 1.5 min.
|1.||With a pencil and paper, draw an outline of the outside perimeter of your dried clay piece.|
|2.||Place a piece of shelf paper on the microwave kiln base.|
|3.||Place your project on the shelf paper.|
|4.||Place microwave kiln into microwave oven. Heat until it becomes orange. you can see the inside through the hole in the lid. Turn off.|
|5.||*****SEE NOTE ABOVE ABOUT FIRING TIMES! . Heating time: Approximately 3 minutes until the color changes. If the hole on the top does not change to an orange color, add extra one minute by setting the microwave timer. You may repeatedly add extra one minute until the hole on the lid becomes orange. TURN OFF|
|6.||NOW RESET FIRING TIME : This depends on weight of your project! (See chart in previous paragraph). Firing for more than the chart shows, you risk melting your project. Pre-firing a test piece is recommended!|
|7.||After firing, take out from microwave oven at once, using gloves. It usually takes from 20 to 30 minutes to cool down. Do not open the kiln while it is still hot. Use tweezers to pick up the fired piece and then:|
|8.||Check the size of the fired piece against your drawing in #1. If the contraction of the fired piece is less than 8 to 10%, it is not successfully fired. You need to follow steps from 2 to 6 again to complete firing. Art clay silver contracts from 8 to 10% when fired. It is important to do this step for checking if your piece is successfully fired.|
You will notice that the surface of the fired piece is white. This is due to a crystallization of the silver powder. I remove the powder with a small brass brush.
Silver cleaning solution: sterling silver contains copper and when it gets into high temperatures, it develops a black covering, called fire-scale. To remove it you can mix 1/2 cup warm white vinegar and a tablespoon of salt and soak the piece in it for 20-30 minutes. Note: do not use the stainless steel tweezers with this solution.
I have not tested bronze clays, etc. but if you decide to try them be sure to check the metals table above. Also, if you use a material with flammable binders (cork) you might cause soot buildup in your microwave kiln. I think that would not be a good thing.
Copper enameling is basically something that we are aware that people are doing with Microkilns, but since it's really not our line of business I don't have a lot of details for you.
The key to copper enameling and the Multipens (liquid enamel in a pen -
see above) is that the surface needs to be really clean (although their standard
practice is to acid wash the pieces before decorating anyway), and that an
etched surface will have a better chance of adherence of the multipens.
As far as time for the Microkiln, etc goes, I really can't tell you exactly. Because there's no way to get a thermocouple in the microkiln, the temperature will have to be judged by eye - the color of the glow will tell you how hot it is.
This seller is a glass artist and has not experimented with ceramics. The following instructions are compiled for your convenience.
Mr. Ludwig's linked contribution also has directions for firing ceramics.
It is possible to fire ceramic all the way from greenware through bisque to glazed pieces. Here are two cautions for you. First the greenware must be FULLY dried because if you put a piece of ceramic that is even slightly damp on the inside into a microwave kiln it will explode and splatter clay all over the inside of the microwave kiln. This does not damage the microwave kiln but it is messy and obviously you lose the piece. Second if you are going to bisque fire in the microwave kiln it takes almost twice as long as the glaze firing and you still have relatively soft (underfired) bisque. This can create little bubbles in the decoration when you fire the glaze and it also makes for a relatively weak finished product. I recommend using bisque that has been fired in a regular kiln firing because it works better and more reliably. However if you have to bisque fire in the microwave kilns it can be done taking note of the 2 cautions above (i.e completely dry the piece and bisque fire twice as long as your decoration firing time).
IN SIMPLER TERMS, THIS MEANS THAT YOU SHOULD SELECT PLAIN, UNDECORATED, ALREADY-GLAZED CERAMIC PIECES FOR MICROWAVE KILN CERAMIC PROJECTS (EXAMPLE: A TILE PURCHASED FROM A HOME IMPROVEMENT STORE). DECORATE WITH MULTIPENS. OTHER GLAZES NEED HIGHER TEMPERATURES THAN CAN BE OBTAINED IN MICROWAVE KILNS.
|1.||Place a piece of kiln fiber paper on top of the base of the kiln to stop sticking.|
|2.||Place glass, ceramic or metal piece which has been decorated with Multi pens* on to the fiber paper.|
|3.||Place the lid on the kiln and place into the microwave. Close the door carefully to stop any movement of the piece.|
|4.||Switch on the microwave for the required period. PLEASE NOTE THAT TODAY'S MICROWAVE OVENS HAVE HIGHER WATTAGES AND TESTING AT SHORTER FIRING TIMES IS RECOMMENDED.|
|5.||Put on heat resistant gloves as kiln will now be hot.|
|6.||Check that kiln is glowing before taking out of the microwave. Open the kiln to have a quick look to ensure fusion has been completed. If not, return to the microwave for a further 1 minute.|
|7.||Place the kiln on a heat resistant surface.|
|8.||After cooling the piece may be removed.|
Ceramic Arts Daily published an excellent article on using microwave kilns for ceramics work. Read the article here.
I also found the following chart on the internet regarding ceramic firing temperatures which indicates that china paints are best for microwave kiln projects.
Here are some of the more common cone values and approximate firing temperatures:
Microwave kilns reach a temperature of 1652 degrees Fahrenheit.
Store your microwave kiln in a DRY place. If it has absorbed moisture, dry it thoroughly and then do an empty fire (1-2 minutes) before using.
Moisture will damage your microwave kiln. Your projects and all glue must be BONE DRY before firing!
Use the lowest firing temperatures and shortest firing times possible. Underfire rather than overfire. You can always go back and redo what didn't work and add more time until you get it right.
Do not open the microwave kiln while the outside of the kiln is still hot. Wait 20 or 30 minutes before opening it. Thermal shock will lessen the effectiveness of your kiln AND it is unsafe to open it while it is so hot.
Don't allow your project to touch the interior sides of the microwave kiln. Leave plenty of clearance for glass to "crawl".
If at any time you see tiny cracks on the inside black lining, these can be repaired with the "Repair Kit". Development of tiny hairline cracks in the lining is normal and they do not interfere with the container function. If you should see a bright white light inside the Microkiln when you turn on the oven, the container won't heat uniformly, so we suggest that you repair any crack following the Repair Kit instructions.
Repair kits are available if your microwave kiln should ever need repair from an overfired piece of glass which explodes and hits the side of the interior and causes damage to the black lining, or from aging. As microwave kilns age with use and firing times lengthen, a "black" repair kit can be used to return it to shorter firing times. To recoat the entire top, sand the black coating on the inner surface with a piece of sandpaper. Rotate the kiln top as you sand. You do not need to remove all the coating.Sand until the interior is white to gray in color. Apply a new coat with a 1" paint brush. Apply a second coating after 24 hours. Allow the kiln to dry completely before firing
You will receive a $10 refund on the purchase of a repair kit if you purchased your microwave kiln from me. (Request must be included in comments section when you order the kit. You must order under the same name! Limit one repair kit per order.)
Generic replacement bases for small microwave kilns and repair kits for all sizes are available from this seller.
If the base should develop small pits over time, you can remove them by sanding lightly with fine sandpaper. Wrap the sandpaper around a block of wood to ensure a level surface OR place the sandpaper on a flat surface and rub the base on it in a circular motion. Do this outdoors and wear a mask.
Periodically visit www.microwave-kiln.com to view updates to this information and other products that are available for your microwave kiln.
AND HAVE A LOT OF FUN!!!!
Sharon Griffin's contributions WOW!!!!!!! Thanks, Sharon!
|LAYERING AND SHAPING A PENDANT
Round the corners of a base which will be capped with a piece of glass with larger dimensions (an overhanging edge). This will help prevent shattering at the edges where the cap slumps over the corners.
Close the microwave door very carefully so your stacked project won't move!
You can safely affix small pieces of glass to be fused together as a stack of three pieces using a small portion of Elmer's glue. When the glue dries the glass will not slide or topple over. I never did four pieces. (Contributed by Jack B. Ludwig)
A stacked project generally should total 1/8" high. I find more control when I fire the bottom two layers and then add whatever else needs to be added and then refire.
A 1"x1" stack of 2 thin layers will eventually turn into a round, domed button if overfired. As you fire a 1"x1" square and then add another layer and fire, the corners of your project will "round" and a third firing will round it even more.
If you roll a small piece of Bullseye Thin Fire shelf paper into a small roll (tube) and put it between two pieces of glass with the edges sticking out on both sides, it will make a channel that you can string chain through.
When making a multi-level piece, fill empty spaces in with clear glass to prevent bubbles. (Sharon Griffin's tip).
Dichroic glass requires hotter temperatures to melt than regular fusible glass.
CERAMIC GOLD PENS
Gold ceramic pens fire successfully in my MicroKiln. I fire for three minutes, let cool, then apply and fire a cap. Do this in two steps to allow any gasses to escape before adding the cap. There is a distinctive smell when firing and the shelf paper will look "charred". My observation is that neither MicroKiln nor microwave oven is harmed. Do not fire more than three minutes!
Dichroic "Scrap Packs" are sold by weight. I have been disappointed because I purchased them with the intent of making pendants. The pieces seemed fairly big, but the pieces were so irregular when I cut a square, the majority of the piece of glass was left as even tinier useless scraps. I have grouped some of these scraps on top of a black fusible square and make some pretty pendants, but the point is if you need to make rectangular or square pendants, don't rely on scrap packs for bases. Count on scrap packs for making decorations.
|These tips were
contributed by Sharon Griffin.
An S shaped crack is caused by two
different thicknesses of glass fired too fast. The thin part
gets hotter than the thicker part and causes thermal shock. I
got this when I put a tack fused piece back in the microkiln to
fire it a little longer to make the design a bit less sharply
If you need to use a torch for glass work, you can buy a regular plumber's torch at the hardware store and ordered a pinpoint tip for it. Saves lots of money over ordering a jewelers torch!
I have found that black dichroic fires really fast. Clear glass (dichroic or otherwise) takes a lot longer.
Different colors of glass fuse at different temperatures.
A good way to test how different glass will fuse is to put several 1/4" squares of different colored glass in the MicroKiln together. The pieces must not touch each other. Test fire them and see which ones turn into perfect little balls, which ones are starting to draw up, and which ones are unchanged. It's interesting to see the difference
|HOW TO ASSEMBLE A BASIC STARTER KIT:
Many of my customers ask for me to assemble a kit of supplies for them because they don't know what supplies and materials to buy. Just place the following individual items in the shopping cart (www.microwave-kiln.com) and skip the ones that you already have.
Microwave kiln (you must supply your own microwave
oven and a heat resistant surface for a hot kiln)
To make fused glass pendants using a pre-made kit::
THE CONTENTS OF THE FUSEWORKS KIT IS AS FOLLOWS. YOU CAN USE THIS AS A GUIDE TO MAKE YOUR OWN KIT: