Metal Thickness for Doors on Cooking Chamber

Discussion in 'Smoker Builds' started by pianov, Mar 27, 2014.

  1. I have a cooking chamber on my masonry smoker (fire box is off to the side in its own box) that is about 34" long, 22" deep and 17" tall. I have a really rickety wooden door and lid made of wood - well, actually, it's been like that for a good 15 years now. I want to replace the top and doors. I wish to make the top a half-circle shape, thereby increasing the height in the center of the CC by 17" or so. I'm not sure what to make the half barrel top out of - likely either masonry, steel or wood. I wish to make the doors out of steel. I'm thinking of making a frame for the doors of 1/8"x1"x1" angle iron - for the top half of the doors I will order a half circle bent of the same steel. Then the doors themselves, I'm thinking of using 1/8" plate with 1/8" bar welded around the perimeter of both doors (so the perimeter edge of the doors will be a total of 1/4" thick).

    Is 1/8" plate a good thickness for the doors? Is that all I need for the doors, or should I add the 1/8" bar around the edges as described above?

    Below is a picture of a set of cast iron doors that I'm using as a design guide - I basically want to make the same thing, only out of steel. This is my first time trying to post a picture, so who knows what will happen!

    Thanks!

    Terry Farrell

    Tampa Bay, Florida


    And here is a photo of my smoker as is currently is (FB on left and CC on right top):

     
  2. Hello Terry.  I would use nothing less than 1/4" plate and I would use a 1/4" bar around the edge.  IMHO anything less will warp and you will be disappointed.  Just my 2 cents.  Good luck.  Keep us posted.

    Danny
     
  3. Thanks for the response. Wow! 1/4-inch? I thought quarter-inch was recommended for a firebox, but not necessary for a cooking chamber where the temperatures pretty much never exceed 300 degrees F. I'm not trying to argue at all, but rather I just want to be sure. I just wonder if you aren' thinking a good thickness for a firebox rather than the cooking chamber doors.

    Really - 300 degrees (of course, usually more like 200 to 230 degrees) will warp 1/8" plate steel that is reinforced around the edges - and perhaps across the mid-section like the one in the picture? Again, not trying to argue, but 1/4" is a lot tougher for me to work with as my TIG welder is a small one......  :)

    And thanks again!!!

    Terry - near Tampa Bay, Florida, USA
     
  4. I was just looking at your picture of your barrel smoker. Is your cooking chamber built of 1/4" steel? My guess it is much thinner (I could easily be wrong, of course). Any warping problems with it, if it is thinner?

    Terry
     
  5. Hello Terry.  I do tend to over-build things.  You might get by with 3?16" or you can even use 1/8" plate and then seal the leaks caused from warping.  You haven't told us so I don't know your metal working skills.  Please forgive me if is sounds I am talking "down" to you; that is not my intention.  What are those cast iron doors on?  I assume you realise that each door is REALLY heavy and the molten iron has been poured into a mold forming one single piece.

    It's not so much of the door warping ON the cook chamber as warping during the building process.  I do feel your pain using a small tig welder.  You also didn't explain your build process, do you plan to just tack the joints and then seal the seams with high temp silicone or do you plan on a seal weld?

    You raise a good point about my offset smoker and smokers in general.  Smokers are usually made from thin gauge steel but the plate for smokers and such things are cut on a shear.  Then the plates are rolled or bent on a press brake keeping to welding to a minimum.  The designs also sometimes take warping into consideration.  The welding is also usually done in a jig to help reduce warping.  Welding techniques are also used; weld so far left to right, start the other end right to left.  Start in the center, weld 6", weld 6" on the left then 6" on the right in opposite directions.  When fitting pieces you purposely tack the pieces out of square or out of level and allow the heat from the tacks to "draw" the steel to square or level.  We all know how well smokers are built, that's why folks sell so much high temp silicone and stove rope.  BTW, the offset in my AV leaks smoke like a sieve and NOTHING fits as it should.

    I hope I didn't offend you; I didn't mean to.  I am also sorry for writing a novel.  I just wanted to explain my thought process.  Also when we are asked a question many times we are not given ALL the relevant facts, so we have to base some responses on the cheapest, easiest to do solution.  If you have access to some of this equipment and/or the metal working skills then you might be ok with the 1/8".

    Good luck.  Keep us posted.

    Danny
     
  6. Hello Terry.  I do tend to over-build things.  You might get by with 3?16" or you can even use 1/8" plate and then seal the leaks caused from warping.

    I do also. I looked up the metal thickness on high-end production smokers and you are correct in that even the cooking chambers are often 1/4" thick.

    You haven't told us so I don't know your metal working skills.  

    Somewhere between pre-beginner and beginner. I aspire to be a beginner. I have made about a dozen or two small welds on odds and ends things and I think one of them actually looked okay. My welding skills are somewhere between nil and whatever is less than that.  [​IMG]

    I hope I didn't offend you; I didn't mean to.  I am also sorry for writing a novel.  I just wanted to explain my thought process.

    No offense taken at all. I really appreciate the information you are sharing. Novel on!

    What are those cast iron doors on?  

    No idea. I found it for sale on ebay - starting bid was $1,000 - a bit out of my league for a set of doors.

    I assume you realise that each door is REALLY heavy and the molten iron has been poured into a mold forming one single piece.

    Being a piano rebuilder, I am actually quite familiar with the characteristics of cast iron (most pianos have a plate of cast iron weighing somewhere around 300 to 600 lbs. or so!

    It's not so much of the door warping ON the cook chamber as warping during the building process.  I do feel your pain using a small tig welder.  You also didn't explain your build process, do you plan to just tack the joints and then seal the seams with high temp silicone or do you plan on a seal weld?

    Hadn't really planned ahead that far. I know so little about welding that I didn't even think to think about that!

    You raise a good point about my offset smoker and smokers in general.  Smokers are usually made from thin gauge steel but the plate for smokers and such things are cut on a shear.  Then the plates are rolled or bent on a press brake keeping to welding to a minimum.  The designs also sometimes take warping into consideration.  The welding is also usually done in a jig to help reduce warping.  Welding techniques are also used; weld so far left to right, start the other end right to left.  Start in the center, weld 6", weld 6" on the left then 6" on the right in opposite directions.  When fitting pieces you purposely tack the pieces out of square or out of level and allow the heat from the tacks to "draw" the steel to square or level.  We all know how well smokers are built, that's why folks sell so much high temp silicone and stove rope.  BTW, the offset in my AV leaks smoke like a sieve and NOTHING fits as it should.

    [​IMG]   Oh man. Alright, forget about me doing ANY welding!!! How about if I just get a piece of 1-inch thick plate cut for the doors and keep it simple?!?!?!?!?

    Seriously thought - what about 1/4" thick and no welding except for hinges and the sort?

    If you have access to some of this equipment and/or the metal working skills then you might be ok with the 1/8".

    Of course, I guess I could always just go to a welder with a drawing and specs and have someone weld something up for me. But what about just a plain 1/4" plate steel set of doors? Wouldn't that be a lot more simple? About the only thing to weld to it would be the hinges, the latch and a piece of bar welded to one of the doors for the seal between the two doors (down the center - top to bottom)???

    Good luck.  

    I'll need it - thanks! I just want to smoke some meat in my smoker. The only reason I am doing any of this is that the wooden top and "door" I made for my smoker was just temporary until I figured out what I really wanted to do - but that was 15 years ago and they are absolutely falling apart. Maybe that is my solution - if a temporary el-cheepo wooden top and door lasted 15 years, maybe I should just make a good top and doors out of wood - heck, those should last maybe 25 years or more! After all, I'm a woodworker - maybe I should just stick to what I do best. Hmmmmmm. I'm going to give that some very serious thought. You've scared the begeezus out of me with your welding info. I honestly didn't know any of that - welding sequences and all that and distortion from welding. Wood sounds better to me all the time.......

    Keep us posted.

    Will do. I'll post pictures. My only question now is whether I should varnish the outside of the new top and doors!

    As you might be able to tell from my description of my welding talents (or lack thereof) and the pictures of some of my piano work below, I am much more skilled working with wood than welding steel!!!

    Terry


     
  7. [​IMG]   Hello Terry.  MY GOD man you got some SKILLS!  Absolutely BEAUTIFUL work!

    Now about the re-build.  Another novel coming I feel.  How about we take some of the welding out of the equation?  The dome top:  I think your description nailed it.  I don't remember the exact measurement of a 55 gallon barrel but it is pretty close ( you will need to measure one to see if close enough ).  Why not a barrel cut in half or 2/3drs what ever the measurements require.  Then drill and screw 1"x1"x1/8" angle iron to the cut edge of the barrel.  Drill and screw that angle into the masonry using some cheap automotive gasket material between to two to seal.  Then use high temp silicone to seal the joints between the angle iron and the barrel.  Cheap and cheerful and no welding needed.  Sand well before screwing it down and coat with 3-4 coats of high temp paint.  If the barrel size doesn't work let me know, I have a second option which is more expensive but shouldn't break the bank.  Now the doors.  With your skills I know you will come up with a latch to finish this off.  I have to assume you have a "fairly" flat masonry surface these doors will butt up too.  Go with 3/16" steel.  There are places on E-Bay that will cut steel to size and ship it to you or you may find someone local.  Allow a good overlap of the doors ( you will understand with further explanation ).  These sheets of metal you get will probably be warped.  Place the bow outward.  2 options here:  1. build and attach you hinges and latches, attach the door and then use high temp silicone to seal any gaps.  2. Buy the narrowest, thinnest stove rope you can find ( E-Bay ).  Using high temp silicone glue the rope to the doors.  Then design the hinges to allow for the thickness and then design latches ( I would use 2, top and bottom ) so that it pulls the door closed and depresses the stove rope gasket.

    That's what I meant about giving advice.  Now I know you have skills we can explore other options.  Hang in.  You will get there.

    Danny
     
  8. If your in Tampa, easy fix! Make two cardboard templates of the doors you want and take them over to Tampa Bay Steel ( over by Orient Jail ) and have them cut them out for you. Might as well go with 5/8" or so, then just drill and tap your hinges on if you don't think you Tig will get hot enough.
     
  9. 5/8" thick steel plate? Are you serious? Or is that a typo? Why so thick for a cooking chamber door? Thanks for the tip though about Tampa Bay Steel - it's nice to know of a place nearby that will do that kind of work. I'm located in the south end of Brandon - John Moore & Bloomingdale Ave. - where are you located?
     
  10. Thanks for the nice comments on my piano work.

    Drum idea is worth some thought. I had another idea. What about making the doors the following way:  Make the perimeter of the doors out of  steel channel - maybe 1-1/4" wide with similar legs - make each frame with legs in. Then just lay a piece of 1/8" steel plate inside the frames filling the entire interior of the frame. On top of the steel plate, add a half-inch-thick layer of fire-proof insulation and then 3/4" or so of wood. So the inside of the door would be of steel and the outside of the door would be wood with a steel perimeter frame and sandwiched between the steel plate and the wood would be a layer of insulation. I suppose seal the steel plate to the frame with high temp silicone or whatever sealant might be best. I could do something very similar for the top. This way there would be minimum welding - just the steel channel frames - I think I could probably handle that - or if not, easy enough to take it somewhere to have it welded together. Then I could even varnish the outside and have it look really spiffy!
     
  11. Well, since we are on a roll, below is the end of a tiller that I made for my sailboat (prior to varnishing) - made of laminated hard maple, cedar, mahogany and ebony.


    Below is a picture of a bridge for a new piano that I made for a manufacturer of new custom pianos. It is laminated of hard maple, ebony and mahogany.


    Below is close-up of same bridge.


    Now if I could only learn how to weld better for upgrading my smoker!
     
  12. Hello Terry.  SPIFFY!  Did you just say spiffy?  Just teasin. [​IMG]   RW was serious about the plate.  I like the channel iron idea.  The channel would need to be solidly welded so you might have to have that done.  The channel can also be rolled to form your dome top; another shop job.  the thin inner plate could then be tacked in and sealed with silicone.  On the outside you could grind the welds flat, leave the steel edge showing and then fill the center with varnished wood.  NOW! since you have a tig welder; if you want to go a step farther, what about using aluminium?  You could the polish the outter edge and have a varnished wood center.  With either, if you have a seal problem add stove rope.  Design the hinges and latches as I said above and your away.

    You do some beautiful wood work.

    Keep Smokin!

    Danny
     
  13. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Piano...... morning..... Very nice work..... I was noticing a few tools you use.... Knife and plane..... Did you make the hand plane ??? Dave
     
  14. Knife is an el-cheapo, but is big and sharp - so quite useful. Plane is a smoothing plane - I also have wooden jointer and jack planes. I bought them from a guy in Oregon that makes them. I've had them for more than ten years now and have probably made somewhere upwards of 100 custom piano soundboard with them. If you want the name of the guy, I think I have it out in my shop. He does good work - I've been very happy with the planes.
     
  15. Actually, I thought of an even better idea - a twist to my last idea. Instead of channel, make the frame of angle iron with the leg in of course. The leg in part will have the 1/8" plate laying inside it, put a layer of insulation on top of that and then the layer of decorative wood. And then simply run some machine screws in through the wood into tapped holes in the leg-in part of the angle - or through bolt - whichever. That would be even more simple, easier to build and retain heat very well I should think. I could even put a thin layer of insulation or gasket material between planks of wood so when they expand and contract they won't be splitting and whatnot. I think that would be easy to make and would really look great. I found a place online where I can order pretty much any size angle iron (or channel or round or square - just about any kind of metal) and they will custom bend it for me (as you suggested - roll it I think). Even with my crude welding skills, I actuallyu do think that I could weld something like that up. I wouldn't have to weld the 1/8" steel plate to the angle because it would be sandwiched by the insulation and wood to the angle and also bolted to the angle (by the wood bolts). Perhaps I would want to seal it in place with some high temp silicone. Seems to me that would work well. 
     
  16. Hello Terry.  I like it!  IMHO; the wood will at least need to be 1" thick for stability and I still think you may have some seal problems but you can use the stove rope idea I talked about earlier, OR you can even build up a "gasket" using high temp silicone .  Sounds like you have a plan, now get 'er done and I EXPECT pictures.  I am SURE your woodwork will be something to see.  Keep Smokin!

    Danny
     
  17. I was thinking 5/8" plate because you could have them burn out a frame and the doors out of the same plate, other than welding some tabs onto the back side of the frame, ( anchor points ) there wouldn't be any more welding required. 5/8" is thick enough that it wouldn't warp, and thick enough to drill and tap for your hinges.

    1/2" would be fine too, but cost won't be that much different, anything thinner than half, your going to need to frame it in to keep it from warping.

    Trying to think of some wood work I need done, so as we can do a trade! I got a house down by little harbor on the little manatee, but most of the time I'm in Orlando ( hunters creek ) Except Tuesday when I'll be snook fishing .
     
  18. [​IMG]   Hello Terry.  Told ya RW was serious!  And I agree.  It's the building process.  I welded for almost 20 yrs. and I have built a couple or 3 smokers; BUT If I had questions about building a smoker RW would be my "go to" guy.  That Florida boy KNOWS how to build smokers!!!

    Danny
     
  19. Okay, that sure makes sense. I think that I am leaning toward a sandwich approach for both the doors and the top with an inside skin of steel (1/8"), a layer of insulation, and then an outer layer of wood (likely Sitka Spruce a good inch thick) - all sandwiched into a frame of 3/16" angle iron (steel - with one-inch legs).

    Thank you so much for your input. I hope the snook are biting!
     
  20. Gotcha!
     

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