Simmental Farm 36" Pompeii and 48" Rumford Style Fireplace

[Gulf]

This has been a lot of fun for me. I have been helping a couple of old friends build their WFO and an outdoor fireplace. The oven and fireplace will be part of a huge screened in patio and an outdoor kitchen. We have gotten a good start on the oven and I will try to bring this thread up to date as I get time to post.

The plan is for Don to build an identical oven later for his daughter and son in law. He will be using the same IT, templates, and jigs that were used to build this one. With the experience Don is getting on this oven the next one should be a breeze for him

[Gulf]

The oven stand is two 48" block walls that are tied together by monolithic arches front and back. The blocks were mortared so this forms a true 48" by 48" oven stand. The 32" wood storage area will later be fitted with heavy duty tracks made from old garage door rails for a sliding drawer/shelf. The intentions are for the drawer to be loaded with wood from outside the screen room and unloaded inside the room. It will be used to service both the oven and the fireplace.

[Gulf]

I really like using templates. Just about every measurement for an oven and entry can be drawn in full scale on an easy folding poster board. I have found that you can use the same half of a drawing to include the foot print and also the side view. You can even include the arch brick placement. We used this template first to find the center point of the oven to scribe the curved form. The yard stick that Don using to scribe the form was also used earlier to scribe the radiuses on the template. So, the holes for the pencil are already there if needed.

[Gulf]

The form cantilevers over the stand 6" to either side and 12" to the rear of the oven. I had been mulling over a stand designed or an oven which stood out in the elements with no cover. Cantilevering and rounding the hearth slab at the back lets the water shed directly off a finished dome and eliminates the water pooling at the corners of the protruding hearth stand. The back of this oven will not be under roof.

[Gulf]

We used two layers of 1/4" plywood for the curved form. So when we scribed the form 1/2" was allowed for the final dimensions.

We installed 1/2" rebar in all cores and also for the monolithic arches.

7 weep holes were formed by installing 1/2" pvc pipe in the form. The weep holes were cut to fit just under the top of the finished concrete.

[Gulf]

Check out the wheelbarrow on steroids Don has lots of cool tools that made this project a lot easier!

We poured all cores on this stand. The form got one final screeding after the last pic. But no floating due to having to cover for a storm front.

[Gulf]

Most of the weep holes were easy to find from the top. The rest were easily unplugged with a long screw driver from underneath the form. Each weep hole was scored with a star pattern. We used a skill saw and masonry blade set to about 1/8th" depth.

[Gulf]

We placed 2" mosaic tile sheets upside down and used another template to mark the footprint for the board insulation. It makes it a lot easier if the center line is marked front and back on the hearth slab for future reference. Those marks will be needed for several steps during a build.

[Gulf]

The insulation template was also used for cutting the 3 layers of 1.5" CalSil. Some experienced folks with a good eye will notice that this is scored insulation. Scored insulation has v-grooves that allow it to fit around large diameter piping. I have made several posts on threads warning about not using it for the floor insulation. In this case it was obtained at a bargain price.

I said a "bargain". But, sometimes bargains have hidden charges! We devised a way of cutting wedges on a table saw to fit the holes on a table saw. The saw was fitted with a vacuum collection system. We both wore NP95 masks and had a fan blowing any excess dust away from us. So, we thought that we were ok. ...................We both lost a couple of days of work on the oven with sinus problems. Don had to get a steroid shot. Both of us were thinking that we had contracted Covid. As it turned out, we both had "CalSillyAsstosis"

It's a "silly" disease because we both knew better. Obtain solid board insulation or just live with the air spaces in the crap. It ain't worth trying to fill the gaps IMO.

Oh well. We are both seniors. But, you younger folks that want to live forever need to take warning!

[Gulf]

This is my 11 year old HF saw, ready for another project. It has paid for itself many times over for me. I no longer had all the parts for my improvised commode float to rig up in the bucket. Don saw the need and put a float regulator that he uses in his stock water tanks. This is an economical improvement for folks wanting a clean water supply to their wet saws

[Gulf]

One of the problems with designing an IT is the pivot point. Most that I have seen used so far have (including my first IT and wooden brick) had an offset. That offset can lead to having to make adjustments . For many years I have found myself looking for something that could be used for an off the shelf, no offset pivot for an IT. So far, I have not found it.

Still determined, I decided to build one

Pic #1 is a 5/8th diameter X 2" clevis pin. I cut a notch perpendicular to the predrilled hole for the pin. I heated and flattened a 7/16" all thread. (The thick all thread has enough diameter so heating and flattening to widen the attachment point may not be necessary. However, it will still need to be ground or filed down to fit the notch in the clevis) I then drilled a 3/16th" hole to match the clevis pin hole and a ss bolt.

The bushing in the first pic was not used.

[Gulf]

Married with a wooden brick this creates a no offset pivot point.

Don drilled a 5/8" hole and a slight 3/4" counter sink hole underneath in my old wooden brick at the exact center of the dome floor. We had to rout a counter sink in the top to allow free swing of the IT for the first course and scribing the floor brick.

The exact center point is easy to find for the rough placement of the wooden brick before cutting to find where the wooden brick needs to lie with the full scale template. For the final placement it is easy to mark the direct center on the wooden brick with the center point hole provided in the template. Just line the template up with the center line marks front and back on the concrete hearth.

[SableSprings]

Joe, this is an awesome build thread. Incorporating all the innovations forum members have made these past years makes this into the perfect diy guide. I think that "we" should make this IT design the defacto for building a WFO. Cut the thread stock above the pivot attachment & use a threaded sleeve and this could be sent to another builder in a pretty small box (they'd only need to buy the threaded stock for the other end of the sleeve to reach the projected outer wall). I also love showing the advantages of the cardboard template in doing a build layout.

Great Job! Looking forward to the upcoming posts.

[Kvanbael]

One of the problems with designing an IT is the pivot point. All that I have seen used so far have an offset

Wel... Mine had no offset. Granted, it wasn’t perfect, but at least my dome’s center is flush with the Floor. I only had to drill a tiny hole in the center of my floor to hold a nail.

[Gulf]

Thanks Mike,
Later in the build, or perhaps at the end, I intend to include all the measurements for this 36" oven and also how to draw the full scale template to fit any hemispherical oven..

Kvanbael,
Great job on your IT!. That will do nicely. I particularly like how your design allows for quick removal and replacement of the IT for touchups, clean up, etc.

I will edit the post to read "most" .