Shorty Core + Oven Build and Test

After many years of study and help from this fabulous community, I am proud to present my Shorty Core + Oven build!

The big test firing was yesterday, and after a smoky start I recalled that all decent core tests need some sort of chimney stub to run properly. Slapping on some old HVAC duct got this thing firing perfectly and burning clean with the door fully closed.

My biggest deviation from Peter Van Den Bergs brilliant air frame design is in the intake. Where he doubles up the bottom square-tube to make an air-box, I risked a change to simplify the design by pointing the air intake downward and skipping the double frame member. The intake hole itself is slightly oversized so it gets plenty of air but could be partially blocked if it seemed like too much air (which appears to be a non-issue with Shorty.) All other size specifications for this batch box design where followed precisely based on the development thread.

I wanted an oven, so I reversed the riser exhaust direction to face backwards (which will be into the open void of the brick bell behind the core.) The 16x18 oxide bonded kiln shelf oven floor/firebox roof cost a lot but conducts heat perfectly, resulting in a floor temp of 500F degrees and an air temp of around 400F. I'll set a metal rack on the bottom to bake on. Oven door is insulated with a piece of ceramic fiber alternative board, also coated in Satanite.

Please see the picture descriptions for all the juicy build details. I'm happy to provide more details if requested.
Here is a video of the test burn: https://youtube.com/shorts/uIy8fhlbHoA?feature=share

Many thanks to Peter, Thomas Rubio, and everyone else who's been willing to post builds and answer questions that lead up to this. I will follow up with the brick bell build in my dining room which will begin soon!

Sweet Matt!
Looking great, Shorty gets an oven!
You did a great job designing and assembling this.
I will need to speak with the admissions board on your behalf.
In my opinion, this build qualifies you to skip apprentice training and receive full rocket scientist status, with all the outstanding benefits that come with it!

thomas rubino wrote:
In my opinion, this build qualifies you to skip apprentice training and receive full rocket scientist status, with all the outstanding benefits that come with it!

I did build one successful DSR2 and a functioning but abandoned DSR3 core before this, so those may be my apprenticeship. But let me prove I can figure out masonry on the bell before making claims to any titles.  

Sorry Matt, but when I say I'm making a call, I do so.
And having an in with the awesome committee staff, they usually do not dally with my requests.

Congratulations on your new title!  You have indeed earned it!

Having said that, and lavished praise on your formidable accomplishments...
IF... you Screw up building a simple brick box, then I will have no recourse but to request a revision of your status.

Hi Matt, I was waiting and expecting for somebody bolting an oven to the reversed Shorty core, and you did. A white oven like yours is probably less complicated as compared to a black one, I realized while I was viewing your pictures.

The deviation from the airframe design might play up when the core is really, really hot. The air box as the lower door frame member means that the air, going through two changes of direction could pose a friction point for the air stream. Maybe you could widen the intake opening even more, so that the air streaming doesn't need to make sharp bends. That the air intake is larger doesn't make any difference, the proportions of the core are the limiting factor, combustion-wise.

In my design, the air box under the door is also functioning as a threshold, so the ash won't fall out when the door is opened. And in a recent implementation I added a tiny slit high in the inside of the air box, and it appeared to be working as a boost when the core need to heated up. The slit is thin as a normal cutting disk, and only 4" wide. Done in the prototype of the Pepper Shaker.

All some random thoughts.

Peter van den Berg wrote:
The deviation from the airframe design might play up when the core is really, really hot.

I appreciate the notes Peter! Knowing this was not built to your tested specs, I was careful to build in a way that could be changed later if needed. I'll keep an eye out for struggles at high temps. While I don't have a testo, I did get a thermocouple and many probes so I can monitor multiple points. My threshold isn't as tall as yours, but I did leave an inch of airframe above the firebox floor to hold the ash in.  

Would an oven like that have some sort of active temperature control?

Coydon Wallham wrote:Would an oven like that have some sort of active temperature control?

Nothing precise, which is why the goal was to hit an acceptable range around 400ish with materials alone. Just to be in the ballpark of a baking temperature. That said, if it errs on the side of too hot I can add an adjustable vent to the oven door to release heat. To maintain temperature, add more wood. Which is something this core tolerates better than previous designs.

Good job Matt!
Are you going to cover the slit in the floor (that exposes T-bar part) when you build your heater inside?

Cristobal Cristo wrote:Good job Matt!
Are you going to cover the slit in the floor (that exposes T-bar part) when you build your heater inside?

Yes, in fact the floor needs to be half an inch higher. I just didn't have the material yet so I built up the back of the firebox with some insulation (ceramic fiber alternative) to smooth out the transition into the port. And stuffed the middle gap too. Only for the test of course.

I'm going to get some ceramic tiles to line the floor for a very low cost bottom wear layer.