Small Portable Tandoori Oven Build

[eLuke455]

Re: Small Portable Tandoori Oven Build

Now it was time to work out how to fix the lid back on! We were hoping to implement something a little more elaborate, as it would have been nice to have fixing tabs on the inside as it would be more visually pleasing...but it all got too difficult so we fixed 3 tabs on the outside.

The idea was to weld 3 x 10mm stainless nuts to the inside of the keg. The lid would then be fixed to the keg with 3 bolts through the tabs. Sounds pretty strait forward.

First task was to make the tabs using a sturdy drill press. Again, drilling stainless is not as easy as you would think.

The lid was aligned with the keg and taped up with strong gaffer tape. 3 tabs were welded into place, equally spaced around the keg. This was all fairly strait forward.

With the tabs in place, we found another excuse to use the plasma cutter. That is, to blow the hole for the bolts. It "kind of" worked as you can see from the final picture, but the holes need significant work with a step drill to finish off (complicated by a lot of flat battery drills). Still, it was probably quicker than trying to drill 3 x 12mm holes in 3mm stainless.

Cheers
Luke

[Wiley]

Re: Small Portable Tandoori Oven Build

Luke, excellent thread and a great job so far.
Looking like alot of fun :-)

And a question for Rossco: The people you know who cook naan in their WFOs, do they have some sort of holder or applicator for sticking the bread to the hearth like is used to stick the bread to the inside of the tandoori ovens? Or is it slid in off a peel as if it was a untopped pizza skin?

Bests,
Wiley

[dmun]

Re: Small Portable Tandoori Oven Build

The tool for applying Naan to the inside of the tandoor is called a bread pad. This page has a picture of one, and a nice photo essay about making naan.

Naan | The Fresh Loaf

I don't see any reason why the same pad couldn't apply naan to the dome of your oven. Haven't done it myself: I just cook flatbreads on the floor.

[heliman]

Re: Small Portable Tandoori Oven Build

And a question for Rossco: The people you know who cook naan in their WFOs, do they have some sort of holder or applicator for sticking the bread to the hearth like is used to stick the bread to the inside of the tandoori ovens? Or is it slid in off a peel as if it was a untopped pizza skin?

The WFO ones that I have seen being made are done directly on the oven floor.

I suppose that raises the question then: "are these actually naans?" Probably not!

[eLuke455]

Re: Small Portable Tandoori Oven Build

After plasma cutting the holes were a little rough. To clean these up, we used a step drill. The biggest challenge in this process was finding a battery drill with a decent battery.

With the holes cleaned up, we decided the best approach was to align the lid and tabs with bolts in the nuts, and then weld the nuts onto the keg. All seemed pretty forward. Bolts and nuts tightened but not too tight. Although tricky, the TIG hand piece could fit through the hole in the top of the keg.

The welder (Rik) did cop some arc-flash in his eyes because the welding mask LCD panel (located just above the eyes) was shielded by the keg. A small head ache was the only result, but this was an interesting safety lesson with these LCD type masks. If your LCD is obstructed from the ARC, it won't shield....

All three nuts were welded, although we had to turn up the current due to the large thermal mass of the nut and bolt.

As we tried to undo the bolts, we discovered (or should I say remembered) that Stainless Steel is notorious for galling. Well, each bolt seized up after 1/2 of a turn. We emptied a can of RP-17, various types of oils, applied heat, to no avail.

1 x 17mm spanner and a lot of torsional force and the 10mm bolts were broken off (although I thought the welds on the nut would give way, but they did not). Another wonderful lesson in mechanical engineering - torsional vs shear breaking points (and who says electronics engineers know nothing about mechanical engineering ehh???? ). Out came the Dremmel and cut off wheel to remove the nuts.

The above process was repeated, but this time with anti-seize compound on the threads. Success was the result (don't have a photo of this unfortunately).

Cheers
Luke

[eLuke455]

Re: Small Portable Tandoori Oven Build

With the metal work done we could pack up the welder and plasma cutter and start the brick cutting. As mentioned earlier we destroyed the 5" tile cutting wheel we used earlier, so not to be outdone this time we sourced a 9" brick cutting wheel. I'm not sure we needed the 9" wheel, but bigger is better as they say.

Those 9" grinders are one beast of a machine and seem to have a mind of their own so anyone trying this at home be extra careful.

First step was to mark up the bricks with some chalk.

Second step was to fill the bottom of the keg with some vermiculite and start laying out the bricks. The final layout was complete and although we could have left a bit more on the bricks, it turned out to be fine in the end.

The final step involved some juggling of vermiculite in the base, along with the side wall bricks and aligning the pot to sit nicely in the lid. This was not helped by things not be entirely square, but you get that with angle grinders.

Cheers
Luke

[heliman]

Re: Small Portable Tandoori Oven Build

Fascinating build - thanks for all the effort you have gone to in documenting and photographing the whole process.

Hope to see it in action VERY soon...

[ThisOldGarageNJ]

Re: Small Portable Tandoori Oven Build

Hey Luke,
Very impressive, THanks also for keeping such a great photo diary....

Good luck with the rest of the build

Mark

[eLuke455]

Re: Small Portable Tandoori Oven Build

Thanks for the comments guys!!

Now, as per the plan, the next requirement was the side wall bricks. These were the 25mm fire bricks simply cut in half. A test placement around the inside perimeter of the keg showed that some smaller bricks, cut and on angle near the door, would be useful, so we cut those as well.

I was unable to find a small amount of fire rated mortar, and to be honest, the oven would actually work without any mortar, but I decided it wouldn't be an oven project with mixing mortar and getting muddy! I added a small amount of vermiculite to the mortar to assist with insulation, but with hindsight it was such a small amount the effect would be negligible. However, we are engineers and just love to overcomplicate things so we were happy.

The base bricks were set in place by packing mortar around the edges. Then the side wall bricks were placed in sequence, with the cut edge facing the brick, so as to have the terra cotta pot sit on a smooth brick edge. I probably should have partially filled the air gaps with vermiculite at this stage, but I guessed that some vermiculite would fall into those gaps anyway.

The terra cotta pot was then placed onto the wall of bricks. As mentioned earlier, it took quite a bit of effort to get the pot to square up and fit nicely into the lid cutout. This was because the terra cot pot was not cut exactly square, and it was very hard to get the base vermiculite level. After we found the magic "spot" (which required rotating the pot about 20 times) we took note of how the pot was orientated, then ensured this was put back the same way.

One concern we had was the naan slapping process. For those of you familiar with making naan bread, it takes a decent slap to get to the bread to stick to the wall of the oven. I did not want the terra cotta moving, so we cut some wedges and placed them around the pot to lock it into position. This was a very simple idea but very effective. Note that the pot is NOT mortared onto the brick wall. I still don't know if it will crack, so for future servicing I have left it without mortar.

The next tricky bit was the gap above the door (no detailed photo of this). This was packed up with small bits of broken brick (they were supported by the bracket we welded on earlier). Mortar was placed over to the top to stop any vermiculite from falling through. Mortar was also placed next to edge wedge to keep it in place. We probably went too far with the mortar, but we were in that "What else can I do with this left-over mortar" mode.....

[eLuke455]

Re: Small Portable Tandoori Oven Build

With everything in place, vermiculite was carefully poured around the Terra cotta into the air gap. The lid was placed back on to the keg, and the pot nicely fitted into the lid cut-out.

Now you would have thought at this stage we would have taken 50 photos to reflect on our great job now complete...but we actually didn't take a photo of the completed unit! (Silly us).

Anyway, you can see that the lid cut-out was retained to make a lid for the Tandoori. This is only temporary was it will be too hot to handle for normal operation. I did destroy about 3 flap disks on the orbital sander in the process of de-burring the edges. That stainless steel is harder than it looks!

Last but not least, it was time to pack up and put the Tandoor aside for the mortar to set and dry, but not without first testing it with a chicken!

Test firing and manufacture of the tandoor cooking rods is next up...I'm hoping to get my hand on a thermal imaging camera for this so stay tuned for more updates....

Cheers
Luke

[heliman]

Re: Small Portable Tandoori Oven Build

...I'm hoping to get my hand on a thermal imaging camera for this so stay tuned for more updates....

Wow - this is now going high-tech!!!!

[eLuke455]

Re: Small Portable Tandoori Oven Build

OK - We are now on the downhill run!

The next task on the "To Do" list were some cooking implements! Skewers were required to cook our Tandoori Chicken on, and these are not the sort of skewers you can rush out and buy.

A quick trip down to the local stainless steel merchants and I returned with two lengths of 5mm 316 stainless rod. Using a vice, some oddball scrap parts lying around the shed, we built a bending jig.

The rod was inserted into the jig, and slowly bent around the former. The rods were cut to length using a dremmel and then a point was formed using the belt sander (to assist with skewering the meat).

[eLuke455]

Re: Small Portable Tandoori Oven Build

With the meat skewers done, it was time to make some tools specifically for the naan bread. The first tool was fairly strait forward, this consisted of a hook to hook the naan and prevent it falling off.

The naan scraper was a little more challenging. This tool is designed to pry the naan off the oven wall. So it needs to be thin and flat, a bit like a flat blade screwdriver.

Starting with the rod again, we heated one end until cherry red using a propane burner. This was then bashed on an anvil. The process was repeated until the end was fairly flat. The end was then finished on the belt sander, with a final touch up being done with some emery cloth. The result was a professional looking instrument!

[eLuke455]

Re: Small Portable Tandoori Oven Build

With the Tandoor ready it was time to fire it up.

First step was to light some charcoal. As mentioned earlier, the type of charcoal in use is not your normal wood charcoal, but a manufactured wood charcoal that is very dense and burns with a good even heat.

We often have a Chimenea lit when eating outdoors at night, so I used this to light the Charcoal. A few small pieces were slowly added to the bottom of the Tandoor (I took several hours to make sure everything had a chance to dry out). Temperature hovered around 150 deg cel.

[eLuke455]

Re: Small Portable Tandoori Oven Build

Slowly more and more charcoal was added, and I played with the ventilation and lid positions to get an idea of how this would work. I sourced a K-type thermocouple for temperature measurement, and was quite impressed when the oven settled at 415 deg cel.

Needless to say, it was time to skewer the chicken and cook. Now I did make a few mistakes at this stage. The chicken pieces I used here had a little too much fat in them, and this subsequently melted and then caused a flare up. It wasn't too bad, but further research has revealed this can be a problem. The solution is to cook and rest, basting in your marinade between cooking times and not using too fatty cuts of meat.

The chicken turned out pretty good in the end. Shown is a photo of the chicken after 10 mins of cooking. I rested it for 10 minutes, then cooked another 10. With hind sight, this should have been 5, and the chicken was more charcoal than I would prefer, well cooked, but incredibly moist inside.

After we did the chicken, I rolled out a few naan bread for a test. Like a true amateur, the first naan just fell off my applicator into the coals. The second one was gently slapped onto the terra cotta, and promptly fell off into the coals. The third and subsequent naan were really slapped onto the terra cotta and the result was fantastic! They were light and fluffy, were crisp on top and bottom. There was some variation in cooking, but I'm sure I'll get the hang of it.

All up I was very impressed with my Tandoor oven. I'm sure going to make it a regular feature at my house. It's also been great to build this project with my mate Rik and for me this has been an excellent learning experience, particularly with some of the interesting metal work that I have not attempted before.

We are already postulating about what to do with the second keg...A charcoal spit roast bbq maybe, then again a fractional still has it's merits too.

Cheers
Luke