Raku,Top hat, treated wool furnace?

Discussion in 'Furnaces and their construction' started by Red97, Mar 8, 2018.

  1. Red97

    Red97 Copper

    Wanted to go a bit more in-depth on these types of furnaces.

    Not to clog up the other threads.

    I see this type of furnace as a very possible option for me to get started.

    Would like to expand on the different possibilities for this type of furnace construction.

    I deal with "kaowool" type insulation quite often. And have seen some very simple furnace pictures

    Can it really be made to work well for aluminum?

    I'm thinking A10 size crucible, some fire bricks, and a propane burner.

    Interested in the different types of coating. Are they diy solutions? Or something store bought?


    What kind of service life can one expect? Seems with a solid cage a lift off lid, would be possible. Along with being able to lift off the entire body.

    Any cons to starting with this type of furnace? Need to do something different with the burner setup?

    Any and all help/pictures appreciated.

    Joe
     
  2. Red97

    Red97 Copper

    20180308_190540.jpg 20180308_190547.jpg

    I'll probably have a couple boxes left by the time I finish my current project.

    Just 1" thick.
     
    Jason likes this.
  3. Jason

    Jason Gold

    Sure it will work fine. Somewhere around here I had a video of a guy down near Sarasota that does bronze in his all kaowool rig. Ya just gotta coat the inside of that sucker with something. Inhalation risk and all that. You are sitting on a gold mine of kaowool. Have you seen what the thieves on fleabay get for a foot of this stuff? Ask OCD, he's gone into the microcrystalline wax business, you should join him with your plethora of kaowool. Save a 2 boxes for yourself and a box for me!:p

    Here he is. I don't think thats coated. His lungs, I don't really care. Never aim a torch directly at the side of a crucible. How did this clown get so many views? lol


     
    Last edited: Mar 8, 2018
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  4. Frank Clark

    Frank Clark Copper

    The insulation really is not that expensive by the roll. But we get ours delivered from LaPort I believe so ours comes by truck. I’d think ups would deliver a single roll.

    But if I was selling it a few feet at a time, I’d charge big bucks. I absolutely hate touching it. If not real careful you can itch for days.

    If someone in DFW area needs just a bit they can contact me. If we have left overs you might be able to cut yourself a piece.
     
  5. Jason

    Jason Gold

    I've been getting mine from Armadillo Clay in Austin. I didn't know you hail from DFW... Are you working with a guy named Humberto on casting a bust or head of someone?? Someone around here is and I cant figure out who it is. Reason I ask, someone in FT worth has a line on CHEAP silicon. Like REALLY cheap and I'd like to find them.
     
  6. Red97

    Red97 Copper

    Seems if you applied a coating, and some sort of mesh to the outside. This type of setup would hold up well for quite a few aluminum melts.

    We will probably blow through 10-13 boxes of it by the time this project is done. It dosent like being compressed and moved a lot...
     
  7. FishbonzWV

    FishbonzWV Silver Banner Member

    Joe,
    Here's my A6 furnace, 20 lb propane tank shell, 2" of wool and a Satanite hotface.

    [​IMG]

    This the 1/4" Satanite coating, I think I used about 5 lbs. http://www.hightemptools.com/refractorycoatings.html

    [​IMG]

    [​IMG]

    I'm currently working on an A10 furnace of the same type.

    [​IMG]
     
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  8. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Satanite is the coating.

    http://www.hightemptools.com/refractorycoatings.html

    FishbonzWVa has many melts on his conventional style furnace. He's in the process of a bigger version now but here's his original build.

    http://www.alloyavenue.com/vb/showt...d-Burner-Build&highlight=FishbonzWVa+Satanite

    It will add some weight and is a little pricey but can be brushed on the wool. If you are just thinking of a lift off, I doubt it's needed, maybe just a little rigidizer.

    Such a build will handle aluminum fine. Buy an A10 Super Salamander crucible, make and open ring shank, build a Reil burner and go to it. Then you will have to master making foam patterns.

    Best,
    Kelly
     
    Red97 likes this.
  9. Red97

    Red97 Copper

    Would an A10 be the right size for those cylinders? Or a 6-8 be better?

    On the same hand if it will fit an A10 any issues using a smaller crucible if needed?
     
  10. Red97

    Red97 Copper

    Thank you for the pictures and info.

    I think something like that will be quick and easy to get me started.

    Not sure where this endeavor will take me, but I figure something more durable can be built down the road.

    Sounds like you can get pretty good service life with a setup like yours though.
     
  11. Jason

    Jason Gold

    5lbs to coat that thing for 15bucks??? That sounds really reasonable.
     
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  12. Red97

    Red97 Copper

    Did a little searching. Seems a few use a simple weed burner to melt aluminum.

    Found these while looking for reil burners.

    http://www.hybridburners.com/products.html#trex

    3/4" t rex seems about on par with the size of most of the assembled pipe fitting burners.

    Any pros/cons to either direction?

    Don't imagine I will need a forced air burner for aluminum. Maybe for a 50lb + melt?

    Such thing as too hot of a burner? Seems with a hot face coating the wool should stand a chance.
     
  13. PatJ

    PatJ Silver

    I bought two hybrid burners, the 1/2" Shorty, and the 1.25" Foundry burner.
    They both work well and are naturally aspirated, so they don't require a blower.

    I originally intended to melt iron with the larger unit, but could not get that to work.

    I use them these days when I want a quick and simple aluminum melt.
    I think the larger one would melt quite a large crucible of aluminum.

    I opted to by a Hybrid burner because when I started backyard casting, I did not have the time or desire to build my own.

    I now use a siphon nozzle burner for iron and for larger aluminum melts, but I still use the smaller Hybrid burner quite a bit for smaller aluminum melts with my small furnace, using a #10 crucible.


    A home-built option to these burners is the Reil burner.
    There are several variations of the Reil that can be found online.

    Edit:
    A drawing for a Ron Reil burner is here:
    https://www.google.com/search?q=ron+reil+burner&client=firefox-b-1-ab&tbm=isch&source=iu&ictx=1&fir=lB1Jp6YnmqngNM%3A%2Cnl0cO5UiBKkS7M%2C_&usg=__apZOMWpoMWjV8ORWfRSr2KU-GeQ=&sa=X&ved=0ahUKEwikodS_gt_ZAhWF3YMKHae9ASYQ9QEINTAC#imgrc=lB1Jp6YnmqngNM:

    I think if I were going to build a propane burner, I would build this one instead of a Reil, since it could easily be used with or without a blower.
    https://www.google.com/search?q=ron+reil+burner&client=firefox-b-1-ab&tbm=isch&source=iu&ictx=1&fir=lB1Jp6YnmqngNM%3A%2Cnl0cO5UiBKkS7M%2C_&usg=__apZOMWpoMWjV8ORWfRSr2KU-GeQ=&sa=X&ved=0ahUKEwikodS_gt_ZAhWF3YMKHae9ASYQ9QEINTAC#imgdii=Tj4ooMbJPFydCM:&imgrc=HaJbFO7WazDCUM:
     
    Last edited: Mar 9, 2018
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  14. Red97

    Red97 Copper

    Thank you.

    I think I will start with an #10 crucible.

    Possibly go bigger down the road. You think the 1.25 hybrid would be way overkill for my needs?

    Thinking the 3/4 seemed just about right.

    I may possibly build one. Still up in the air about that.
     
  15. PatJ

    PatJ Silver

    I think a 1.25 hybrid would be overkill for aluminum, especially with a #10 crucible.
    A 1.25" is more of what I would consider for forge work, and is often use in pairs on forges.
     
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  16. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    There's no problem with using a smaller crucible in your furnace. You also don't need to charge the crucible full for every melt. You almost always melt more than you need and just pig off the remainder in an ingot tray. An A10 is a nice size and I use it for most pours. Capacity is 11lbs of aluminum. An A10 is only about 6" in diameter by 10"tall. If you just had a lift off wool basket, add 2"/side for gap and 2"/side for wool, and 2-4" above the crucible, your wool furnace body is only 14"D x 10"T....that's nothing when it comes to wool mass. I'd suggest leaving the furnace body open barrel with a 2" thick disc shaped lid and 3-4" vent hole. That way you can easily view the melt progress and access the crucible to skim and/add charge with the burner still running to keep heat on the melt.

    I tend to agree with Pat. A burner with a 3/4" pipe delivery tube will generate more than enough heat for an A-10 size furnace in aluminum service. You can buy a burner or just make one with a handful of fittings and -030-035 mig tip. You will need a higher pressure propane regulator. The T-Rex burners are nice, and not to take anything away from them, but there's no magic there. If it's just a matter of available time as opposed to thickness of wallet, search Propane burner on eBay you'll get plenty of hits with regulator and hose for ~$100-$150 range. Stainless is nice for taking the heat. Or there's the Harbor Freight weed burner route.

    For the furnace base you can just fashion something with loose firebricks that has a flat base and burner pocket. This would be somewhat of a temporary furnace but really just depends on how often you will use it. If it will be frequent use, and you just want to roll your furnace out and light it as opposed to gathering up the bits and stacking bricks, a more permanent build would be recommended. In use, you're only talking a few minutes difference in melt time at most.

    Best,
    Kelly
     
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  17. Red97

    Red97 Copper

    My thought is to use fire brick as a base. Steel mesh for the barrel, along with a mesh top.

    All mounted to some sort of cart/wagon. Just so I don't have to chase pieces when I do want to use it.

    Time is the biggest factor working against me currently.

    If a weed burner or eBay burner will do all I need, I will just go that route. Wasn't sure if the more expensive units were more user friendly or not.

    Figure I can gather all the parts I need to assemble a operating furnace in the day or 2 I have home. Just to get a feel for how everything works.

    Crucible dosent have a "shelf life" does it?

    May be a while before I can actually attempt a casting.
     
  18. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    No but they need to be stored dry and do best if they are seasoned initially and after long periods of not being used. Seasoning is just a slower warm up cycle.

    Best,
    Kelly
     
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  19. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    When it comes to firebrick, there is Insulating Fire Brick (IFB) and Dense Fire Brick (DFB). IFB is available at different service temperatures, usually starting at 2300F and going up. 4 1/2" x 9" is most common size in different thicknesses up to 3". At refractory wholesale places you can usually buy a box of 12 for $3/brick. 2300F IFB looks like ceramic sponge and cuts very easily with a hand saw. It's also fairly fragile. It's a very good insulator and very light. As you go up in service temperature, they become more dense, less insulating, and more difficult (but still easy) to cut, until you get to DFB. DFB has high refractory and strong/durable but is a poor insulator compared to IFB. It also must be cut with diamond or masonry saws like building pavers.

    You'd probably be fine with 2300F IFB but I'd suggest 2600F. You can buy mortar and glue them together, fashion them into a circle and put a band clamp around the perimeter, our just use them position loose. You can carve a provision into the IFB base for your burner slot our just put a mouse hole in the base of your lift-off furnace body. Use 1/2 and IFB for your plinth.

    Best,
    Kelly
     
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  20. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    To give you a feel for working 2300F IFB, Here's a high power heating element I improvised to cure a refractory casting in my furnace rebuild. It was two bricks stuck together with some mortar and then I used a coarse round files to cut in the heater grooves. Took about 15 minutes to shape the brick.

    25 Improvised Heating.JPG

    Best,
    Kelly
     
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