Resizing 55 gallon 200L Drum

Discussion in 'General foundry chat' started by Tops, Jan 31, 2023.

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  1. Tops

    Tops Silver Banner Member

    The more I think about an A20 x 55 gallon furnace build, the more I feel I would be better served with something smaller. Has anyone successfully taken top and bottom of a tight drum, split the main seam, and reduce the diameter? My barrel is about 23", looking for 18", so I would need to cut out 5*3.14 or so and then tighten the cicumference and weld. Or is this a case reworking a 10$ barrel is pound foolish to buying a shiny 110$ 30 gallon? Used 30 gallons seem rare here.
    Thanks!
     
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I started with barrels for both my furnaces too because it was years ago and that seemed to be what all the hobbyists did but with the amount of fab I did to them, I could have just as easily started from scratch as I have a slip role. If it's just the skin for a traditional lift out crucible furnace, and you have some fab skills, the skin doesn't really need to be that structurally substantial. All that said, with the cost of metal these days, a barrel can usually be had at a fraction of the cost. Those smaller barrels are out there. Water heater tanks can also be an option but messier with a lot more stripping and scrapping. Have you checked Craig's list or FB market place for barrels near you? Also, unless you have some space constraints, the OD of the barrel doesn't prevent you from making the ID whatever you want. Just fill the diameter difference with wool/ceramic fiber.

    Best,
    Kelly
     
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  3. Tops

    Tops Silver Banner Member

    Too bad I scrapped out a water heater just before getting into this hobby...

    Thanks Kelly. Making just the bore smaller would be easier than making the barrel smaller to match.

    The barrel came from Craigslist. I could reach out and see if they ever get in smaller ones.
     
  4. Petee716

    Petee716 Gold Banner Member

    Beer keg, but make sure it’s stainless and not Aluminum. An A16 is the biggest I can fit in mine. The bore is 10” so maybe it would be a bit small for you.
     
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  5. Tops

    Tops Silver Banner Member

    Oooh, shiny! A16 would be fine. Are you running LP/NG or oil? Thanks Pete!
     
    Last edited: Jan 31, 2023
  6. Melterskelter

    Melterskelter Gold Banner Member

    FWIW I really like my shortened full diameter 55 gallon barrel build. I use it with both an A20 and an A25. I did use a 30 gallon to build a furnace for a 20 once, but never again.

    Denis.
     
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  7. Tops

    Tops Silver Banner Member

    Thanks Denis, appreciate the data points for barrel and crucible sizes.
     
  8. Petee716

    Petee716 Gold Banner Member

    I run waste oil/diesel (80/20). I preheat with a simple propane burner, usually for about 10 minutes, and then switch out to the oil burner. I sometimes preheat with straight diesel using my oil burner from a gravity fed tank (kitty litter bucket) and just switch over the fuel lines to my oil tank once I’m up to temp. The oil burner has a Hago-type (Delevan) siphon nozzle.
    The gravity setup was my original burner fuel setup until I put my pressurized oil tank together, so I keep it around for burning up things that I don’t want in the pressure tank like dirtier diesel that I’ve used for parts cleaning or more explody stuff like stale 2cycle fuel, small amounts of old gasoline mixed in, etc. Everything gets filtered through a tee-shirt. It works pretty reliably but I’ve subjected my neighbor downwind to a number of smoke plumes from flame-outs over the years and I can see their patience wearing a bit thin, so I use the propane method most of the time. It’s a slam-dunk. If I were running straight pressurized diesel like Melterskelter or preheated waste oil like myfordboy I could probably light it straight off without preheat, but economy has to prevail over efficiency (at least in terms of fuel), and the preheated oil is just a road I haven’t gone down (yet). Time will tell.

    Pete
     
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  9. Tops

    Tops Silver Banner Member

    Thanks Pete. Is there a build thread for this furnace? What kind of space do you have floor to crucible and crucible to inside of lid?
    Talked to one of the guys at the supply house for firebricks and refractory today and I am getting kind of excited. Just need to make a couple more decisions and commit.
     
  10. Petee716

    Petee716 Gold Banner Member

    I can’t remember exact dimensions right now as my furnace enclosure is covered in snow, but my plinth holds the crucible at least above the top of the burner so it doesn’t get directly hit by the incoming stream of air and flame. I like my crucible rim around 2-4” from the lid and stack blocks on the plinth to elevate the crucible to accommodate different sizes.
    My build was documented on Alloyavenue (boy, time flies), but there are some really instructive builds here.
    Here’s one
    http://forums.thehomefoundry.org/in...lting-furnace-build-thread-highlight-reel.18/

    Pete
     
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  11. Tops

    Tops Silver Banner Member

    Thanks Pete, it is fun to follow the links and see the pics in those old threads and stuff.
    I am pretty much set on a shorted but full diameter 55 gallon barrel for the build, doing the initial metal work while I make final decisions on refractory materials. It is supposed to be around/above freezing this coming week so I might go 'play outside' and step away from the 'puter for a while. I think I got a piece of angle iron long enough to start a rolling base... :)
     
  12. Melterskelter

    Melterskelter Gold Banner Member

    One thing I did on my 55 was to split it from top to bottom so I could spring it open to wrap it around the assembled hot face and wool blanket. Yes, some extra work, but using mig it did not take very long to stitch it back together. And I was able to get more wool (3 layers) around the face instead of 2. I did compress the wool slightly. But I do not think the small amount of compression will have a measurable effect on its insulation properties. I wrapped the wool with a few hoops of tie wire to hold it in place until I got it wrapped.

    Denis
     
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  13. Tops

    Tops Silver Banner Member

    Thanks Denis, I had not considered that it could take some effort to install the insulation into the barrel.
     
  14. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Another possible method for installing the outer fiber blanket is to wrap the hot face in ceramic fiber blanket, then wrap the outside diameter of the fiber blanket in polyethylene film to compress it and hold with tape, then slide the furnace shell over the hot face and blanket and pull the slipery film out once installed.

    Best,
    Kelly
     
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  15. Tops

    Tops Silver Banner Member

    Thanks Kelly, I could see that working too.
    I am leaning toward using a reciprocating saw for the 'chopping' as opposed to cut-off wheels or torch. Previous material in barrel was olive oil that was drained well. Thinking about a few gallons of soapy water and maybe even some CO2 gas as I have a small bottle. I don't do much with sheet metal so I do not have a nibbler or air shears. I would love some better welding gear for this too but trying not to add even time and $ chasing down new tools so welding will be stick.
     
  16. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    A thin cut off wheel on a grinder or a bimetal blade in a jig saw would make short work of it.

    You might be surprised how thin gauge the barrel might be. My 30 gallon barrels were beautiful but were ~28ga! Don't recall what the 55gal were. Stick is a pretty tough way to go on thin gauge sheet metal compared to MIG or TIG. I'd be blowing holes in it left and right.

    Best,
    Kelly
     
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  17. Melterskelter

    Melterskelter Gold Banner Member

    Opening up the barrel does make working with the wool a lot easier. But, I agree with Kelly that stick sounds tough on thin metal. I think my 55 was more like 22 ga---but still plenty thin. With mig set up correctly I could move rigth along after making tacks every inch or so and being careful to move around on the seam so as not to concentrate heat too much. You might be able to help some in that regard if you lay, maybe, a 1" wide piece of at least 1/8" convex-peened steel behind the seam so that you are not welding on air. Mind you I have not done that on stick but I have used that method on mig and tig when feasible and it sure helps. I suppose it would be similar on stick.

    Denis
     
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  18. Petee716

    Petee716 Gold Banner Member

    I like Denis’ suggestion about the steel strip. Depending on how you intend to design your lid lifting mechanism, you may end up with a couple of straps around the circumference of the barrel anyways, so a continuous weld may not be necessary. I bolted my mechanism straight on because I was confident in the metal thickness as well as the rigidity of the shell form.
    The picture shows how it’s bolted on. It was taken at some point during the firing process of the build. There’s charcoal on top of the lid because I used 1/2 plywood as a form when pouring the lid. That plywood got captured as a result (I missed that fine fact in the planning phase) and I opted to burn it out. Once it was finally all burned out (I should have found a way to cut it out; the burnout method was a loser) I filled the cavity with koawool and covered it over with a piece of 18ga steel. I ended up abandoning the chains on the lid. The single point mount works fine.

    51C11C16-DBD6-4643-A0CE-03203198294F.jpeg

    Just for grins:


    Pete
     
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  19. Tops

    Tops Silver Banner Member

    Thanks Pete, thanks Denis., thanks Kelly!
    The excitement is building along with the realization that there are still many details to work out like the lid mechanism.
     
    Last edited: Feb 5, 2023
  20. Tops

    Tops Silver Banner Member

    tops_barrelcut_setup.jpg

    tops_barrelcut_results.jpg
    Cut a barrel, the saber saw and bimetal blade(s) was a good combination, less tool to manage than a reciprocating saw and less anxious for me than using a cutoff wheel on an agle grinder. I would have done better making it about 1-5/8" (4cm) taller as the shorter dimension placed my saber saw on two different height ridges, making it so that if I tilted the saw heel to toe, the blade would come out the cut, bounce on the barrel, and snap before I could shut it down. I was consuming 1 blade per foot (30cm) and had 6 feet total (180cm) to complete but only 4 blades. I began to understand the failure mode at broken blade #2, put on a face shield over my safety glasses, and finished the remaining 4 feet (120cm) of cut on blade #3. I did run a gallon (4L) of soapy water into there before cutting but I think the below freezing weather would have been enough to keep the olive oil from getting to its flash point., plus the blade did not seem to get very warm, just made nice little chips provided I kept it in the barrel.
     

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