Twin burner furnace.

Discussion in 'Burners and their construction' started by Ironsides, Jan 23, 2024.

  1. Ironsides

    Ironsides Silver

  2. rocco

    rocco Silver

    Can't see why it wouldn't work however, I don't like it because the flame from the upper burner is going to impinge on the crucible, probably reducing the crucible lifespan compared to a single burner or more conventional twin burner furnace.
  3. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Only benefit I could think of is a narrower burner stream in a small furnace might allow for a slightly larger crucible, but placing the second burner higher in the furnace seems unhelpful for achieving optimal flame dwell time and heat from both burners.

    They are probably tooled up to make the smaller burners economically, standardized to use multiples of them in their various forges and related products, and need more than one of them for enough heat in the melting furnace.

  4. Petee716

    Petee716 Gold Banner Member

    I think it fits in the better-than-nothing category. According to the currency conversion it looks like $200 USD, don't know about freight. Not bad for turn-key and probably a good fit for some hobbyists. Pitched as a dual use unit I'll bet they get some sales.

  5. rocco

    rocco Silver

    FYI, on their American site, it's $179.99 USD, fast shipping included. If nothing else, the price is right, you'd have a tough time building something comparable for that money.

    BTW, they advertise this as a dual use furnace, this is a screenshot from the manual.
    Furnace as forge.jpg

    Attached Files:

    Last edited: Jan 24, 2024
    Tops and Petee716 like this.
  6. HT1

    HT1 Gold Banner Member

    I built a twin burner furnace
    I eventually had to lose the second burner, could never get the burners output to equalize so one burner was overheating and burning up the other. with forced air there is little reason to do two burners, you can just kick up diameter and air flow on a single burner to whatever BTU/Hr you want/need

    with venturi burners I would think that problem would be 10 fold one burner eating up the other, that said a second burner would be the only way to increase the output of furnace, though, one tank one regulator would be a new limitation
    , also the one above the other burner design is sure to impinge on the side of the crucible, if you want to use it as a forge as they recommend, it would be OK , but as a furnace it will have issues to overcome

    V/r HT1
  7. metallab

    metallab Silver

    Rather useless compared to the single burner design most of us use. The Kaowool wall is not lined with a Satanite / Fermit like layer on the inside, so the user should wear a respirator or at least a face mask when the furnace is running. Moreover, the Kaowool wall will wear faster.
    With a single burner and forced air I attain 1500 C easily within 20-30 minutes from a cold furnace.
    They specify a '12kg crucible', but the capacity should be specified in milliliters or any other unit of volume, not mass due to the large difference in density between metals. Even copper alloys are three times as heavy as aluminum.
  8. HT1

    HT1 Gold Banner Member

    They Specify 12Kg of Molten Gold and then contradict themselves with this quotes: "This 12kg large capacity means you can melt 26kg gold, 14kg silver, 12kg copper, or 3.6kg aluminum. What are you going to make first?"

    if that is true you are right near an A8 crucible size ,

    but again it lists as a farrier forge and metal melting furnace, and they are bragging about the Stainless shell, stainless has issues, a little inconsistent heat and it will warp BADLY, so after first use it will be a wiggly metal mess, additionally SS will be offgassing Nickle if you are concerned about Nickle allergies, and onced heated it will lose a lot of the Corrosion resistance, so why?

    throw in that a farrier forge has a Hard, Normally firebrick floor, which is included, without proper support that brick will fall over when the Forge is rotated to be a furnace, so perhaps they are advocating a reassembly of the lining which will be impossible more then once or twice,
    I already mentioned the Burners are too High and will probably impinge on the crucible .

    I did find a reviews on youtube

    Note he has the US, not Australian version, and it is a paid review
    additionally i found which is not paid
    and also not paid, this Guy Vet VS world did several videos, that are much more illuminating , the lid fell apart
    another paid review
    and another paid review this one shows the lid warp in all it's glory, also watch the Pizza box flask:eek:

    NOW the thing i will point out: Vevor did not send their furnace to a metal caster , and none of the reviews are from a metal caster , and they are all very wishywashy

    My opinion This is the cheapest furnace of this size you can get , it is below average , I would destroy it in a year for sure , But for a FNG ("friendly" New Guy) it would be a good starter kit , serious metal casters will quickly have to add to it alot , and it seems to be hit ormiss if Vevor sends ridgidizer so be prepared for that

    V/r HT1
    Ironsides and Tops like this.
  9. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    You can say that again. On one hand, these things reduce the entry cost and increase the number of people that are interested in starting a home foundry hobby. On the other hand, it almost makes it too easy because there are a lot more people that can charge $175 to their credit card but don't have any shop/machinery experience, a single clue or any common sense about what they are doing, and though they're willing to fire up their credit card they won't invest another hour or dollar to do it safely.

    Now, I do get a bit tired of people that watch my videos and complain that I left out parts, and I say, yah just subscribe or surf my channel because there are entire videos dedicated to those subjects. Then some even complain, "why can't you just answer the question here in this post"? And there inlies the whole issue.....the YouTube culture.....

    They think I should be able to tell them every thing I know or that they need to know about casting in a single 15 minute video, and even though I invested hours to make those other videos, they don't have minutes to search and view them. I also get tired of the safety police. I mean, they watch an entire video of a guy turning a chunk of foam into an intake manifold in his garage/driveway, and the only comment they can come up with is I shouldn't be pouring over a concrete surface.....because they know nothing about steam explosions but read about them......and it will never happen with a small aluminum spill on a concrete surface.....there, I do feel better now, but I digress. :)

    HT1, Ironsides, Tobho Mott and 2 others like this.
  10. cactusdreams

    cactusdreams Copper Banner Member

    Does seem a little silly to me on a small furnace. You can only burn so much gas in a given space before you're just wasting fire and money blowing out the top. Don't see how two burners changes that. Looks more like a vertical forge.
    Jammer likes this.
  11. Ironsides

    Ironsides Silver

    Welcome to the youtube club.
    HT1 likes this.
  12. metallab

    metallab Silver

    The stainless shell is not a big issue. Here my small furnace made from a stainless steel kitchen trashcan. The difference with the Vevor is the thicker walls (50mm /2" Kaowool) and the inside of the wall, bottom and the plinth is painted with Fermit (a Satanite like substance). At the moment of the photo the furnace is used about ten times with only one time slightly repainting a few spots. The shell got a bit brownish and only around the burner gate it is more heat damaged. It is one of the best furnaces I have made.
    I use this with natural gas and forced air and after 20 minutes it heats to about 1350 C, well enough to melt copper alloys.

    Attached Files:

  13. HT1

    HT1 Gold Banner Member

    in 2 of the 5 videos i posted above the Stainless lid warped so bad it would not fit on the furnace and in one of those the warping caused the Kaowool to fall out, so at least in the Subject furnace, warping IS an issue
    Im glad you are not suffering from warpage

    V/r HT1

    P.S. I could not find anyone that used that furnace more then 3 times so the quality of that furnace and it's design is unproven( to me at least)
    Tobho Mott likes this.
  14. HT1

    HT1 Gold Banner Member

    you are right , But a venturi burner since it creates it's own airflow has it's own limitations, they overcame the max output of that particular burner by adding another.

    and yes adding forced air will overcome this issue, but that makes this "furnace" an entirely different product , and the product is designed to be both a furnace and a forge , and as I originally said I suspect it is very average to poor at both

    V/r HT1
  15. metallab

    metallab Silver

    With the difference that a forced air burner increases the temperature in the furnace chamber with about 200 C.
  16. Ironsides

    Ironsides Silver

    In the second video I had a look at his videos and found one where he tried to melt steel with that furnace. No surprise that it failed. I know the veg oil guy did a paid review on a similar furnace which claimed it could melt steel so don't believe everything you read on what a furnace can do.
  17. Petee716

    Petee716 Gold Banner Member

    I think folks sometimes confuse burning with melting.
    Tobho Mott likes this.

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