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Thread: How Many Beer Keg Furnaces can one forum Tolerate ?

  1. #11
    Senior Member r4z0r7o3's Avatar
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    OMG NO! Not another Keg furnace! Lolz. Perhaps the things happen to be about the right size, well-made, and are nicer looking than rusty 55-gallon drums?


    I too used SS refractory needles, and have no cracks in the furnace base or body (IIRC). Though it's not been used heavily yet, so time will tell. I still think everything cracks eventually, it part of the circle-of-life. So probably not worth worrying about, cracks just mean you're normal and your non-cracked furnace was delivered by aliens.
    "Things that are complex are not useful, things that are useful are simple."
    - Mikhail Kalashnikov

  2. #12
    Senior Member Zapins's Avatar
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    I did let my refractory dry out for several weeks before firing. It was also fairly covered and in a cool dark place so it probably dried very slowly and helped prevent cracks. No light bulb used inside. Just 2 to 3 weeks of waiting. No needles used either.

  3. #13
    Senior Member OCD's Avatar
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    I did the same letting it sit for approx. 3-4? weeks or so and then did the light bulb ordeal for a couple more weeks.
    Just never got around to fire curing it plus we have nasty humidity levels down here to deal with.

    I only noticed the previously mentioned MiNute cracks in mine "after" I cracked the heat up as posted in my furnace build.

    The only way I see getting around the issue is to "only" use CFB coated with ITC or similar or do the preheat / slow heat process.
    Can't speak of the IFB as I haven't used it as of yet but Ming did with his mini furnace and DID experience cracking so we're back to the rapid firing which apparently is the Devil which causes the cracking issue(s).

    Unless I'm mistaking, industrial furnaces/foundries use the needles and still experience crack issues as well.
    I wonder why, maybe because of rapid firing processes?

    I wouldn't worry about cracks to be honest.
    Hell, you'll spend a fortune on the slow firing process (propane) unless your running a oil burner and have unlimited supply.

    It'll be cheaper to just fire it up, get your grove on and replace the refractory when that time comes.

  4. #14
    Senior Member Tobho Mott's Avatar
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    I went out of my way to find an ACTUAL 12" sono tube (they come to the store nested like Russian dolls, so there's usually one that is really that size if you check through the ones they have) for the inner form so that my 1" hot face would leave exactly 2" for two layers of 1" ceramic blanket inside my 18" drum shell... Only to discover that the 1" thickness of the blanket itself seems to only be a nominal measurement - it was a pretty tight fit getting it in there. Not quite tight enough that I had to cut up my drum though...

    Jeff
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

    How I built my oil furnace | My Photo Album | My Videos

  5. #15
    You going to polish that thing when it's done?
    Visit me: WWW.HandcraftedLanterns.com
    "Sometimes by losing a battle you find a new way to win the war"
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  6. #16
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    The slow initial firing is especially important when there is still water in the refractory, since heating the shell too fast will flash the water and cause steam explosions, which are going to chip out and pit the refractory.

    The last dryout I did, I used perhaps 1/2 tank of propane at most, and this furnace will have a fraction of the mass that one did, so I would anticipate using 1/4 tank of propane or less.

    From a thermal shock standpoint, it is much better to ramp a burner up relatively slowly, and I think I am going to use perhaps three needle and ball valves on my siphon burner so I can start on a low heat, then change to medium after a few minutes, then go to full power.
    Multiple needle valves would also give a a gph selection of say 1, 2, 3, 4, 5 etc. gph, that could be pre-calibrated.
    It depending on how many needle and ball valves you want to buy as to what extent you want to take that.

    Maybe mount the ball/needle valve arrray remote from the burner so that it could be used with any siphon burner.
    I will have to establish three or more settings for the combustion air damper to match the fuel flow.
    I wonder if that is something that could be automated, like a carburetor.
    I guess I should either make or use an actual carburetor.

    I do have a buffing wheel that I use with granite countertop work, but I am just not into polishing foundry equipment.
    It was a big deal for me to paint all my lifting tongs and pouring shanks, but I did it just so they would look a little better.
    For me, I would rather save the time and effort for polishing the castings that I make.
    Very few people will ever see the furnace, but a lot of people will see the castings, and the last thing I want people to say is "Wow, your furnace looks great, but your castings........not so good".

    Pretty much everything I do foundry-wise is experimental, so if I ever get to the point where I feel I have it all worked out, then I guess I could make it all look nice.
    For me, it is function over form.
    If you don't have good function, then does the form really matter?

  7. #17
    Senior Member OCD's Avatar
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    Caster, Jason is just ribbing (teasing) you...... or me. lol

    I was bored, that's the "Only" reason I polished that dang thing.
    Although it will make for a good web site advertisement if I ever start selling them.

  8. #18
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    The good thing about a polished furnace is that if you ever break your mirror, you can still comb your hair.


    Edit:
    I looked at motorcycle carburetors online, and they are pretty cheap, but I think in the interest of simplicity and reliability, I will stick with needle/ball valve combinations.

  9. #19
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    I slow dried my ~1" hot face with a 100 watt light bulb insider with the top covered for about a week. Let the heat bleed out the tuyere... Then it sat for a couple more simply because I didn't have the time to fart around with it.

    To "fire" it, I just burnt some construction timber scraps in it for an hour-ish...

    I do have cracks now, but I don't believe they have anything to do with how the refractory was tempered.
    FLAME ON...!!!!

  10. #20
    I really slow dried my furnace out, lol. I built my furnace over the winter as a downtime project, and to dry it out, I just put a large garbage bag over top of the furnace and left it in the basement. It sat in the next room to our woodburner, and during the winter, it gets so dry that it'll make your nose start to crack and bleed if you dont put pans of water on the registers. The furnace sat in the basement like that for around 3 months till the weather got nicer. After that, I did what j vibert did and had a wood fire in it, which we just sat around it and roasted hotdogs and marshmellows over it for a few hours, lol.

    On the upside of all of the keg furnaces, if they ever throw a party on this forum, it can truely be a kegger, lol.

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