Vertical Air Baths
New Ideas in Heat-Treating Blades!


This is a story about what happens when a kiln manufacturer is presented with a challenge and thinks outside the box to find a different solution.  All of our manufacturers go to great lengths to provide our customers with the best designs possible to get the job done, whether it be in glass, ceramics, heat treating, or even industrial heat work.  This blog is about how one of our manufacturers came up with a new solution through experimentation, innovation, and perseverance to create a different approach to heat treating blades.  Even if you aren't a bladesmith, you might find this creative process an interesting read to get a better idea of how innovative our manufacturers really are.  

So, what is a Vertical Air Bath, and how did it come about?  To find out the answers to these questions we went right to the source, Mike Glotfelty at Jen-Ken-Kilns.
When Mike had a request from a customer to make a heat-treating oven for blades, he started thinking about all of the designs of heat-treating ovens and wanted to come up with something different and more efficient.  Heat-treating ovens for blades are typically long horizontal chambers with elements on the sides and sometime the back of the kiln.    Mike thought long and hard about the best and most effective heating for blades, knowing that it came from salt and sand bath kilns.  If you’re not familiar with those, they feature a superheated environment that the blades can be submerged into.  Mike thought this concept could be applied to a more traditional top-loading kiln design for heat treating as well, so he and his brother Randy got to work designing something completely new based on the chassis of a proven company winner. Smart car companies do this all the time!


The brothers improved on a solid workhorse in the fleet they had previously designed for ceramics and came up with an all-new design for heat-treating blades that has a tall heating chamber where the blades can hang vertically inside, surrounded by heat from 360º; no obstructions of floors or props, just pure heat coming from everywhere and heating all of the metal to the same temperature at the same time.  Mike felt that this design would reduce the possibility of blade warpage that is sometimes caused by uneven heating of the blade during the heat-treating process. 
Once they had the design concept mapped out, they needed to try it out.  Ideas are great, but unless they work flawlessly, they are just great ideas.  Their first test was the customer in Mississippi who had asked Mike to build him a heat-treating kiln in the first place.  Here is what he got; a tall, vertical heated air chamber with a baffle at the top to keep the heated air trapped in the kiln when the lid was opened.  The brothers designed a slot in the baffle large enough to hang the blades through, along with a system of long pegs to slip through the holes in the tang of the blade that would span across the slot in the baffle and allow the blades to be suspended beneath the baffle.

After several firings with perfectly straight blades, Mike had some ideas on how to make this design even better.  It seemed that opening up the baffle was going to allow the blades to absorb the heat more fully and allow the blades to glow evenly from tip to tang!  Mike and Randy did some tweaking and built another vertical oven for another customer, Kyle in Jacksonville, FL with a larger opening in the baffle to accommodate more blades.  With Kyle’s input and after several more firings with perfect blades, they felt like they had the design concept finalized and were ready for the next step.

Here is where the story gets really interesting.  Mike decided he wanted to take a class to learn how to make blades for himself so that he could better understand the process and better relate to his customer’s needs.  He signed up for a class at Doghouse Forge with Jonathan Porter and brought one of his new vertical ovens with him to the class.  After much skepticism, the participants in the class all decided to try the new oven for their heat-treating processes during the class.  Mike had talked up the advantages of the new design and finally convinced everyone it was worth a shot.  The only problem was that as he sat in the class and learned more about the process of making a blade, he realized that the method of hanging the blades in the kiln was great if there was a hole already drilled in the tang.  But what about the freshly forged blades that hadn’t been normalized yet?  There was no way to get a hole drilled into the dense metal of the tang at this point in the process, so there wasn’t any way to hang the blades the way he and Randy had designed, with a peg slipped through a hole in the tang to suspend the blade. 



As he sat in the class, he remembered that he had a heavy-duty kiln element in his car.  A coil of tightly wound stiff wire, hmm…  What if he cut that coil into segments that were as long as the pegs and just inserted the tang into the tight coil?  The tension would hold the blade in the coil and the coil could be placed across the slots in the baffle just like the pegs to suspend the freshly forged blade.    It was a brilliant idea, and it worked!  Everyone in the class used the new vertical heat-treating oven, and there were no warped blades.  By the time the class was over Jonathan had told Mike that he was leaving the vertical oven right where it was!  It was now part of the Doghouse Forge studio. 


So, what are the advantages of this innovative design? 


· Even, 360º heat distribution, the blade is heated evenly from top to bottom.


· Easily accommodates multiple size blades at the same time.


· Large capacity can hold 12+blades in a single firing.


· No warpage because the blades are held vertically throughout the heating and quenching process.


· The vertical design along with the included castors saves valuable space in your work environment and is easily moved out of the way when not in use.


· A power interrupt lid switch prevents accidental electrocution when the lid is raised.


· Reversible, side-mounted lid handle design allows for easy access to the blades without exposing the user to extreme blasts of heat as the lid is raised.


· Extra elements above the baffle allow for quick return to temp after the lid has been raised and lowered.


· Configurable baffle design allows for multiple blade shapes and sizes to be accommodated in the same firing.


So, there you have it.  A new and innovative design, born of the desire to fulfill the needs of customers from a company that prides itself in doing things the right way, just with a twist. 


There are now five different Vertical Air Bath models to choose from, each with their own unique attributes, and all are competitively priced.


The Virtual Air Bath EDC has a 6” wide and 11” deep chamber.  This is the smallest VAB, but still a great size for those small to medium sized blades.  It is equipped with the 3-key digital Orton Controller.



Jen-Ken Kiln - Vertical Air Bath EDC

The Vertical Air Bath 16 has an 11” wide and 16” deep chamber and will accommodate larger blades.  It comes with the 3-key digital Orton Controller.



Jen-Ken Kiln - Vertical Air Bath 16

The Vertical Air Bath 21 has an 11” wide and 21” deep chamber and comes with the 3-key digital Orton Controller.



Jen-Ken Kiln - Vertical Air Bath 21

The Vertical Air Bath 30 has an 11” wide and 30” deep chamber and is equipped with the 3-key digital Orton Controller.



Jen-Ken Kiln - Vertical Air Bath 30

The Vertical Air Bath Excalibur is the largest of the VABs.  It is 11” wide and a massive 50” deep.  This is a custom VAB 21 with an added chamber.  It can be used in either the 21” or 50” configuration.  Because of the height of this heat-treating oven, special consideration needs to be taken when setting up the work environment.  In the 50” configuration, you will need a platform to work from, a tall quench tank to accommodate the long blades, and taller ceiling height to give yourself ample room to draw out the long blades.  It comes with an AFG 12-key controller standard.



Jen-Ken Kiln - Vertical Air Bath Excalibur

All of the Vertical Air Baths are available for Quiet Drive Solid State Relay upgrades as well as controller upgrades.  Visit us at to explore all of the possibilities that these great heat-treating ovens have to offer. 


Also, check out these great videos of the Vertical Air Baths in action.


Heat treatingHeat treating ideasJen-kenJen-ken vertical air 21Jen-ken vertical air bathJen-ken vertical air bath 16Jen-ken vertical air bath 30Jen-ken vertical air bath edcKiln academyKiln tipsKilnsSolid state relaysVertical air baths

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