Author Topic: Want to build a gas fired deck oven. Any plans available and suggestions? (Read 13380 times)

scott123 · « **Reply #60 on:** July 13, 2012, 03:32:06 PM »

Quote from: Sqid on July 11, 2012, 11:13:44 PM

Trying to find someone "knowledgeable about gas ovens" but even if I do I don't think they will match up to the combined knowledge here.

Richard, while there is a great deal of combined knowledge here, I don't think any of us has ever built a gas oven from scratch. At least I don't think any of us have (Jeff, have you?) Unless you have someone with gas oven building experience at your disposal (building more than one oven), I would either proceed incredibly carefully or not at all.

I've analyzed as many as 60 parts schematics for deck pizza ovens and not a single one has ever had top burners. These bottom heat configurations go all the way back to the 50s. If, for the last half a century, no one's come along with a successful top burner deck pizza oven, there has to be a good reason. It's most likely just a cost issue, but there's a slim chance it might be related to safety. If you can find that person with oven building experience, go with the top burner. If you can't, I would discourage it.

SO many ovens have top heat issues. It's almost the norm rather than the exception. When you go shopping for a Weber for an LBE, you should swing by the pharmacy for a lifetime's supply of aspirin to go with it. WFOs generally require a virtuoso to manipulate. You're not building those kinds of ovens, though. A properly built bottom burner gas deck oven has absolutely no problem churning out perfect NY style pie after perfect NY style pie. The Marsal MBs make flawless pizza. You can mirror the thermodynamics of a Marsal MB. It's just about achieving enough BTUs, a small enough vertical space, proper deflection and a firebrick ceiling.

If you get a gas oven expert and go with a top burner, then I'll share my thoughts on top/bottom btu ratio. Until then, though, my recommendation continues to be 120K+ on the bottom.

One thing to consider re; the steel, is that you'll need some stainless angle steel in weight bearing roles in hot areas, but, other than that, you can use very light gauge stainless sheet in the hot areas and, for the exterior, regular angle steel and very light gauge steel sheet.

I'm curious, can you purchase a gas BBQ grill in Burma?

scott123 · « **Reply #61 on:** July 13, 2012, 03:34:04 PM »

Quote from: Jet_deck on July 13, 2012, 02:02:58 PM

No, sorry I dont. What about adding a brick deck to a restraunt broiler? Aren't they called salamanders?

I was thinking about a commercial broiler this morning. I think it would end up being too much of a hassle to dial in the right hearth temp.

Jet_deck · « **Reply #62 on:** July 13, 2012, 03:51:52 PM »

Quote from: scott123 on July 13, 2012, 03:34:04 PM

I was thinking about a commercial broiler this morning. I think it would end up being too much of a hassle to dial in the right hearth temp.

Even with a steel floor?

scott123 · « **Reply #63 on:** July 13, 2012, 04:16:47 PM »

Yes, even with a steel floor. You'd have hot areas where the steel is exposed and far cooler areas where the pizza is baking and blocking the IR.

Maybe if you used separate square steel plates and you could time it so that, say, if you had four plates, while two pizzas are baking, the other two are pre-heating, and that time/heat is just enough to pre-heat, it might work, but that seems a bit tricky.

Or maybe if you had separate salamanders- but that could get expensive.

shuboyje · « **Reply #64 on:** July 13, 2012, 06:21:29 PM »

Nope, never built a gas oven. My professional training and experience is all on gas fired hvac equipment.

Just to be clear, I don't think there is any issue with a bottom heat only oven, I just think it would lead to a lingers more complicated design phase and then a good deal of trial and error to get enough heat up top. We've probably all seen the work that has gone into getting top heat on a lbe with its MASSIVLY over sized burner and it still ends up a losing battle most of the time. I still really think the extra cost and complexity of the top burner would end up being more economical in time and money at the end of this project.

Safety is easy, it's just a matter of spending the money for the proper equipment.

Sqid · « **Reply #65 on:** July 14, 2012, 08:58:14 AM »

Thanks for your replies guys. I don't want you to get the wrong idea that I'm being flippant about the dangers. I hear you loud and clear - I really do. I do not want to make any mistakes. Although the technical expertise is not really here, its possible to make things safely: over making things to compensate for the lack of math, if that makes sense.

From a newbie's perspective it seems logical to have a top and bottom heater. My woefully under powered oven (40,000Btus 2.5'x3.5'), does produce good pizza. (I promise I will learn how to post pictures!). The bottom stone can store the heat and the top blasts the cornicione with radiant heat from the flame. After about 20 pies in a row its getting tired but its the top that has the hardest time coping. I also suspect that it is a cost issue that prevents them producing such a model. The wankel rotary combustion engine is superior to conventional engines but why upset the gravy train - however I digress! I am running my oven at full blast on the top, 300C and only 211C on the bottom to get an even cook. Fire brick ceiling seems to be a must but to have a burner on top seems to offer many potential advantages.

There is no BBQ culture here per se. There are restaurants selling BBQ style food but the burners are locally made galvanised pipes with holes in them or just a line of wok type burners set underneath the grill. I will be in Bangkok on Monday and hope to find some burners then.

I don't want to go over 120,000 Btus because most of my pizzas are for delivery and I think any advantage in the cook would become detrimental to the product after 20 mins in the box.

I also considered broilers (mainly as a top heat

) but they are also not easily available and they do take some time to warm up themselves.

Shubs - do you think that an AC company will be able to provide the necessary controls that I will need or will I have to get those during my trip to Thailand.

I googled, "thermodynamics of a Marsal MB" and the one hit I got was for pizzamaking.com

Chicago Bob · « **Reply #66 on:** July 14, 2012, 09:14:39 AM »

There was a link posted recently somewhere on this site to some grill/smoker guys making their own pipe burners. Looked neat in that instead of drilling all those little holes they cut slits in the pipe on a band saw. Our Don made a comment about that. Anyway, it looked like they knew what they were doing and were giving safety tips.

Sqid · « **Reply #67 on:** July 14, 2012, 07:03:41 PM »

Hi Chicago - Been searching high and low for that thread but can't find it. Can you remember what section it was in? Interested to have a look.

Chicago Bob · « **Reply #68 on:** July 14, 2012, 10:53:24 PM »

Quote from: Sqid on July 14, 2012, 07:03:41 PM

Hi Chicago - Been searching high and low for that thread but can't find it. Can you remember what section it was in? Interested to have a look.

Don in Mexico commented on that thread...I just searched his past posts an nada! Where it went, I don't Know
I googled (diy pipe burner bandsaw cuts) and you should be good there....here's an example http://www.hobartwelders.com/weldtalk/showthread.php?28224-pipe-burner-build-instructions
Just looked at it a bit more and it is the one I saw on our forum

shuboyje · « **Reply #69 on:** July 14, 2012, 11:22:46 PM »

Earlier in this thread I posted a link to an entire forum dedicated to designing and building burners. It is the best resource on the web I've found on that topic. You can find multiple designs there that have been through numerous "generations" and redesigns that now run like well oiled machines for many people.

Chicago Bob · « **Reply #70 on:** July 14, 2012, 11:44:49 PM »

Quote from: shuboyje on July 14, 2012, 11:22:46 PM

Earlier in this thread I posted a link to an entire forum dedicated to designing and building burners. It is the best resource on the web I've found on that topic. You can find multiple designs there that have been through numerous "generations" and redesigns that now run like well oiled machines for many people.

Squid,

You started this thread......are you reading it man?

Bob

Jet_deck · « **Reply #71 on:** July 15, 2012, 12:35:42 AM »

It's not like any of us are going to travel there and get blown up when the DIY oven crashes. Lets all help him build this bomb.

Sqid · « **Reply #72 on:** July 15, 2012, 02:33:43 AM »

Chicago - Yes am am reading it

. Just don't have the time to delve into every aspect in great detail. Much easier

to ask you lot

!

Shubs - I did follow the link and it looks to be a great and detailed site for someone who is concentrating on making a burner. I'm still not sure what type of burner I should be aiming for or what power or precise dimensions or 1 set or 2. I'm trying to get a better pizza shop and I need a better oven which needs a burner as well as other things. I did bookmark it for later and will have another look at it now but I don't think I'm at that stage yet. I take what you all say very seriously but forgive me if I have to categorize priorities.

Scott - I'm undecided about a top burner, maybe you can give me some reasons why you think that it wouldn't be worth the effort. There are plenty of pizza ovens doing well without it. Although no one of you may have built a deck oven from scratch. Imo, combined the collective expertise is overkill for the project in hand. Its just that last point that concerns me - I am not trying to make the Rolls Royce of ovens I'm just trying to make something thats not available to me here.

Jet deck - I'd feel better with the safety features of a homemade bomb than one made and guarenteed by the Chinese!

Chicago Bob · « **Reply #73 on:** July 15, 2012, 08:35:07 AM »

Quote from: Sqid on July 15, 2012, 02:33:43 AM

I'm still not sure what type of burner I should be aiming for or what power or precise dimensions or 1 set or 2.

Squid,

Don't you think it's about time to make some decissions....I can't speak for the others but I don't think it's good business to have someone do your searching for you , especially if that's not even the direction you end up going.

Bob

Jet_deck · « **Reply #74 on:** July 15, 2012, 09:31:41 AM »

Bob, I agree but consider he is at the upper 1% of the 1% top pizza stuff forum.

Sqid · « **Reply #75 on:** July 15, 2012, 10:21:16 AM »

Bob - I absolutely agree it's time to make some decisions. I shall be in Thailand tomorrow and want to get this project underway.

So far I've decided to go for a 4'x 2.5' oven with probably an 8" or 9" head height (I sometimes make bread for my family and evn eith the 12" clearence I have at the moment it can be difficult getting the pies at the back).

Burners I want will be 2'x3.75'. Looking for even heat distribution. Total of 120,000 Btus. Haven't located a sure source yet but maybe tomorrow! Depending on price and availability I may buy more than one unit or more than 120,000 Btus so I have the option of a top burner. Looked at the forum link you posted and I'm pretty sure that they could help me make what I need but I'm not too good at typing and don't fancy joining just yet.

Regulator is not needed at least on the bottom. If I need for the top I don't know if I can find iot here or maybe in Thailand.

PDI or thermostat. I would love to know more. It seems that a thick stone will do a fairly good job of evening out the hearth temperature but PDI sounds great. Why doesn't every oven use one? Again could do with deciding on this whilst in Thailand.

Ignition systems - They are going to crucify me (on price) if I go to one of the 2 oven suppliers in this country.

Digital readouts - Maybe in Thailand

Steel, shelves. Here in Burma

shuboyje · « **Reply #76 on:** July 15, 2012, 10:23:35 AM »

I just wanted to make sure you didn't miss it

. It's a good resource

You are in uncharted territories, in my opinion you should take as much time as you can to work out a design. I can't even tell you how many hours I spent on the design of my last oven.

Sqid · « **Reply #77 on:** July 15, 2012, 10:37:47 AM »

I was going to add that although steel is available, I'm not sure abou aluminized however I know I can get aluminium sheets.

I would love to design this to perfection but it's really a means to an end. Frankly I think I/we'd be hard pushed to come up with a worse design than what I'm using atm!

scott123 · « **Reply #78 on:** July 15, 2012, 02:25:23 PM »

Quote from: shuboyje on July 13, 2012, 06:21:29 PM

Just to be clear, I don't think there is any issue with a bottom heat only oven, I just think it would lead to a lingers more complicated design phase and then a good deal of trial and error to get enough heat up top. We've probably all seen the work that has gone into getting top heat on a lbe with its MASSIVLY over sized burner and it still ends up a losing battle most of the time. I still really think the extra cost and complexity of the top burner would end up being more economical in time and money at the end of this project.

As I mentioned before, an LBE and a bottom heat gas deck are apples and oranges. Here's a video of what the Marsal MB gas oven can do:

http://www.history.com/shows/food-tech/videos/playlists/full-episodes#food-tech-pizza

The Marsal component is at the 36:45 point. If anyone has trouble playing it, PM me, I have a small clip of that segment. I'd upload it to google but I'm not sure how small the clip has to be for fair use.

Anyway, if you look at the pizzas he's producing, there are no top heat issues whatsoever. There's also very little turning involved, and, because of the thermal mass and btus involved, these ovens recover very quickly.

The secret to the MB thermodynamics is the side vents (see below). This would be difficult to incorporate into an LBE and is why some LBE owners have a hard time, although the greatest headaches are the owners attempting Neapolitan. NY in an LBE isn't all that complicated.

Richard, take a long look at this video, not just for the quality of pizza a bottom heat oven can consistently produce, but because they give you glimpses of the manufacturing process as well as the burner.

They also use metal heat deflectors under the burners, found here:

http://www.marsalsons.com/default.aspx?pageId=2

scott123 · « **Reply #79 on:** July 15, 2012, 02:28:00 PM »

Here's some more shots of other gas oven burner configurations:

http://www.ebay.com/itm/BLODGETT-1048-1060-BURNER-SET-BURNERS-PIZZA-OVEN-/280739190641

and below: