15 February 2018

Let's make a list... Instructors, Workshops & Classes

We need your help!  We are on a mission to create a resource that lists all the instructors and teaching studios from around the US!

Getting an instructor added to the list is easy! Just fill out the form and that's it, you're done! We plan to post the list in the next few weeks so, please add your favorite instructor and share with you friends! The more instructors and teaching studios we have the better!


10 February 2018

For the LOVE of Vitrigraph

Did you know you can make your own stringer for use in kiln-glass work?

Vitrigraph is a special hot glass technique that involves pulling hot glass through a hole in the floor of the kiln. These glass stringers are fine strings of glass that can be used to create your own unique curved forms you can’t find elsewhere.

Bullseye Glass TechNotes 2 describes the vitrigraph equipment and processes developed at Bullseye in the early 1990s by Narcissus Quagliata and Rudi Gritsch, in the process creating a whole new vocabulary for fused glass.

Here are some quick vitrigraph tips:

Glass Feedstock 
Any scrap pieces of compatible sheet glass or coarse frit can be melted down to make lines or “stringers.” Avoid glass granules smaller than coarse frit, as they produce a seedier stringer due to the greater amount of air trapped between the smaller particles.

Loading The Glass
Load the glass into the pot outside the kiln, while it is at room temperature, and then place the loaded pot into the kiln so that it is supported. When working with frit or extremely small pieces of scrap sheet glass, place a small square compatible sheet glass the same color as the feedstock over the hole to prevent the glass from falling out. Then fill the pot with the feedstock.

As we just stated, loading the amount of glass needed for a run of stringer while the pot is cold, and then cooling between runs is the best option. However, if time forces you to do continuous melts, or if it becomes necessary to add more glass to the pot during the melt, here are a few things you need to keep in mind... Always, turn the power off before adding more glass. Use extreme care when filling the pot as glass scraps or frit which miss the pot and land on the electrical elements can damage them. Finally, glass scraps or frit that melt against the refractory brick will corrode it.

Vitrigraph Pot 
Avoid pots with hairline (or larger) cracks, as these will widen as they reach molten glass temperatures. In our experience, unglazed Italian terra cotta pots are the most durable. Avoid re-firing a used pot. The risk of cracking is far greater than the minimal expense of a new pot. As mentioned above, watch out for cracks. They widen and eventually break on firing.

If you want to see in a vitrigraph kiln in action, Bullseye Glass has a great video in their Kiln-Glass Education Online. In the lesson, you can see how they transform a Paragon Caldera kiln into a vitrigraph kiln and how to safely hand-pull stringers.

Most importantly, have fun and enjoy the process! It's a good one!

04 February 2018

Loading the Kiln

Loading a large kiln can often be intimidating. After talking with our friends at Paragon Kilns, here are answers to some of their most frequently asked questions...

Do you recommend 3 or 4 posts under a shelf? It is recommended to support shelves with three posts instead of four. Sometimes four posts can cause the shelves to wobble unless the bottom of the kiln is perfectly even, the shelves are flat, and the posts are exactly the same height. It is best to position posts fairly close to the kiln walls and away from the center of the kiln bottom. This places the weight of the kiln load close to the kiln stand and away from the unsupported kiln center.

How do you load the top shelf so that the ware fires to the correct temperature? On top-loading kilns, placing a shelf too close to the top of the firing chamber can lead to over- or under-firing. To help combat this, try using two half shelves, instead of a full shelf, stagger the height of the shelves. Another option is to mount the top shelf low enough so that element grooves show between the kiln lid and top shelf.

How does one prevent posts from sticking to the kiln shelves? When you unload a shelf out of the kiln after a firing, a post occasionally sticks to the shelf and then drops onto the shelf below. To help prevent this from happening, dip the ends of the posts about 1/8” – 1/4” in a mixture of kiln wash. Only a thin coat is needed.

How important is placement of posts inside a kiln? When possible, posts should line up vertically from one shelf to another throughout the kiln, especially with large kilns and heavy loads. Vertically aligned posts increase the stability of the load and reduce stress on the shelves.

Do you need to fire a top-loading ceramic kiln with an empty shelf in the top of the kiln? It is not required but, a shelf placed in the top of the kiln will prevent brick particles from falling onto glazed ware. This is also useful if the lid is cracked. Some people like to place a shelf in the top of the kiln to prevent the incoming air of a downdraft vent from affecting glazed ware.  Keep in mind, it would be better to fire the kiln without the blank top shelf, since the shelf uses up more electricity.

What kind of gloves can you wear to handle kiln shelves? You can find thin, leather-lined mechanic’s gloves at home improvement centers, or try batting gloves! They are both thin enough for you to load and remove shelves inside a kiln. They will also help to protect your hands against sharp bits of glaze or glass. Always wait until the shelves have cooled before removing them from the kiln.

Is it okay to continue using cracked kiln shelves? You should not fire cracked shelves. They could break during a firing and ruin a load of ware by causing other shelves to collapse.

Is there a way to repair a broken kiln shelf? Unfortunately, there is no way to repair a broken kiln shelf. However, all is not lost, as you can still use the shelf pieces. 
  • Use a tile saw to slice the shelf into horizontal sections. 
  • Place broken shelf pieces under pottery that is decorated with runny glazes or pieces that have too much glaze. 
  • If the bottom of your kiln is uneven, place the broken shelf pieces in the bottom of your kiln to support posts.
  • Use the shelf pieces as smaller shelves to place around tall pieces.
  • Silver clay and enameling: Place hot pieces onto the broken shelf. It is a good fireproof surface.
  • Lay the broken shelf across two half-shelves for even support of a piece with a large base.
Is it okay to fire freshly coated shelves with a glaze or bisque load? No problem! Just allow the shelves to dry before firing them.

What is the difference between loading ceramics in a front-loading kiln and a top-loading kiln? Smaller, lighter pieces are usually loaded in the front of the kiln near the door or on the bottom. This is because these are the cooler areas of the front-loading kiln. Load heavier pieces near the back wall of a front-loading kiln as that is where they will get more heat. The cooler areas of the top-loading kiln are usually the bottom and sometimes the top so, load lighter, smaller pieces in those areas.

27 January 2018

We Checked. We Matched. You Win!

Everyone wants the best price, right? That is why we are introducing the Kiln Frog Best Price Promise. 

The Best Price Promise is our way of sharing our commitment to get you the lowest price possible! Of course, we hope that it is already the price listed on our website but, if it's not... just call or send us an e-mail and we'll get on it!   

Finally, please read the details as all price match guarantees are not all created equal! Many require the store to be online only and require the kiln to be in stock!

With that in mind, here are the guidelines for our Best Price Promise:

  • Almost all kilns are built to order so, the item does not have to be in stock to be eligible for the Best Price Promise. 
  • We can only price match current published prices and not verbal offers from other vendors. We don't care if it's an online retailer or your local shop... we just need something in writing! 
  • The Best Price Promise is not a refund and you do not have to make the purchase before your request. Actually, we prefer if you don't... that way we can make sure that you are happy!
  • The Best Price Promise is valid before your purchase and within 48 hours after purchase. Once your kiln has shipped, we can no longer offer this service.
  • In order to do a true comparison, the price must include all shipping and delivery fees. If the price does not include shipping, get a quote. If our price is still not less, just let us know and will are happy to work with you. 
  • The website or competitor must be an Authorized Retailer or Distributor.
  • Auction websites, like eBay, and special promotions are not eligible.

21 January 2018

COE Does Not Equal Compatibility!

The compatibility of glass is always going to be a hot topic as we see many questions asking... Is Bullseye glass COE 90? Or, can I fuse two bottles together? Unfortunately, the answer to this question is not simple.

The word compatibility refers to the properties of glass that allow it to be heat-bonded with another glass such as in a kiln. For many years, it was believed compatibility was solely determined by the properties of expansion in different glasses. Due to this, an overemphasis has been placed on the numerical value of the COE (coefficient of expansion) of glasses.

The intent of most glass fusers who ask this question is to find out if glass from one company is compatible with glass made by another manufacturer. Regrettably, matching COE's does not ensure compatibility between glasses. No single piece of information will tell you if they are as there are many factors besides COE that determine compatibility. The only true way to confirm compatibility is to to test them.

If you are looking for more detail, Bulleye's Technote 3: Compatibility of Glasses, is a great resource and explains this complex and important matter in greater depth.