Thanks for having me.

Discussion in 'New member introductions' started by Douglas Braun, Oct 8, 2019.

  1. Douglas Braun

    Douglas Braun Copper

    Respectfully, Thank you moderators for maintaining this platform and for the chance to learn and hopefully contribute. I am currently attempting to build a propane f̶o̶u̶n̶d̶r̶y̶ errr, I mean furnace ( like most noobs I am sure... ) and could use all the constructive criticism available. I consider myself well versed in "forum etiquette", so if you see me out of line in any way toward you, well then you probably deserved it :D! If this community is anything like the custom knife and hotrod communities I've been involved with over the decades, I will be hoping to make a few friends along the way. Thanks for having and putting up with me :). Sincerely Doug Braun (aka braundc) 72175110_814690558933312_3814439388486565888_n.jpg 71510010_512743839575834_3425928621259227136_n.jpg 71599877_705208653292309_12840560645636096_n.jpg 72403068_793130784436491_3439783799209066496_n.jpg
    yes it was a craftsman air compressor in a former life...
    Last edited: Oct 8, 2019
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Welcome Doug. We'll look forward to that furnace coming to fire breathing life. What sort of castings are you planning?

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  3. Jason

    Jason Gold Banner Member

    Welcome.... Here is lesson #1 for ya. ;)

    I knew this photo was going to come in handy.
    Maybe I'll make it my avatar.
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  4. Jason

    Jason Gold Banner Member

    Just messing with ya.... :D What's your plan for the inside of your can there? Kaowool? Mizzou?
    What kind of stuff do you want to cast?
    What kind of metals?
    Thought about a casting technique yet?

    Put some wheels under that thing, it will make it easier when ya gotta wheel it outside.
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  5. PatJ

    PatJ Silver Banner Member

    That is a clean looking design.
    Somebody knows how to weld.

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  6. Redwolf947

    Redwolf947 Copper

    Welcome, that's a great start! Look forward to seeing more..
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  7. Tobho Mott

    Tobho Mott Silver Banner Member

    Hey, welcome to the nuthouse! Looking good so far...

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  8. DavidF

    DavidF Administrator Staff Member Banner Member

    Welcome, nice looking furnace you have there...
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  9. Jason

    Jason Gold Banner Member

    Mine was a craftsman air compressor too. I used the bung at the top to screw my handle in it for opening/closing and driving the thing around the garage. The only thing I wish I did different was not make it quite so tall. It could have been about 5inches shorter. Something to consider before adding your refractory. Doug, don't forget to cast a few plinths for that thing of a couple of sizes. That comes down to your location of the tuyere and it's height off the floor of the furnace. (about an inch should be plenty)
    Douglas Braun likes this.
  10. Robert

    Robert Silver

    That furnace is beautiful. But what are you planning to tow with it?!
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  11. Douglas Braun

    Douglas Braun Copper

    Thank you for the welcomes. Jason, great looking furnace! I definitely will be adding wheels! Thanks Pat. It's not as good as it looks. :oops: Robert, haha I was trying to figure out what to do with that hole and saw a tow ball sitting there. It just happened to fit perfectly. :D I was hoping it wont get too hot to touch. Remember, I have never done this stuff before so take it easy on me guys! :mad: I bought a 12.5 foot piece of 2 inch thick #8 ceramic blanket from this place... (probably too thick) 72261640_2270441176586657_4325647282482446336_n.jpg I also have some heavy wire screen I was going to wrap it with before the cement. I'm trying to decide on a refractory cement to encase it in. Was also going to weld some screen inside the lid to hold the wool in place and cement over it as well. I just guessed on the chimney size at 4 inches. trying to decide on the burner next. any suggestions there would be great. burners are overwhelming but necessary research unfortunately. I figured if I could manage some aluminum ingots without sending myself to the burn unit or the morgue, then I might try sand casting. :D I also have hundreds of pounds of copper and brass accumulating and would be tickled pink if I could turn them into something other than scrap! Thanks again for the warm welcome! :cool: Sincerely.
  12. Tobho Mott

    Tobho Mott Silver Banner Member

    You probably don't need to use any screen to hold the ceramic fiber blanket walls in place, the wire won't last long anyhow unless maybe it's buried quite deep in refractory, and even then there may be concerns with it causing cracks as it expands and contracts when the furnace is used. But mainly I just don't think it's needed. I think the screen on the underside of the lid will be the first part to go. Lids are always tricky.

    2" thick blanket is perfect, just wrap it around the inside wall of your furnace shell, cut it so it fits in a nice snug ring, then seal it up behind whatever sort of refractory, rigidizer, whatever. A few of us here have had good results using Satanite refractory mortar as a very thin hot face to seal and protect furnaces built this way recently. I am really liking mine.

    If you decide to use Satanite, just do like fishbonz shows here and you'll do fine:

    I documented my build fairly extensively here as well, probably in way too much detail, but maybe seeing how I got the blanket to stay put in my lid, etc., will give you some ideas.

    There are many ways you could go with this. 2" of ceramic fiber blanket is what I have in my big furnace too, there is a link to that build in my signature. It has a 1" layer of dense castable refractory inside the ceramic fiber, which was a little more complicated to build.

    I'm sure my big heavy furnace can take a lot more abuse than the smaller low mass one over the long haul, and it'll be really great to have if I'm ever in a position to be doing melt after melt on the same day and needing to fill up big crucibles a lot, but it takes a lot longer to heat up from cold, so I've been using the new furnace most often for my typical single weekend melts. It's also super easy to patch up if and when small cracks do form, because Satanite is so much easier to work with than dense castable refractory.

    2" of blanket eats up 4" of your tank ID... Another point to consider, the approaches available to you may be limited by how much crucible you want to be able to fit inside that tank once it's lined, and what type of fuel you plan to use. 4" of your tank is spoken for already. Using Satanite and propane might require another 2-1/2", whereas an inch of dense castable and an oil burner could conceivably eat up twice that and then some.

    Good luck and keep us posted.

    Douglas Braun likes this.
  13. Petee716

    Petee716 Silver Banner Member

    You beat me to it!
    Welcome Doug. That ball will positively get too hot to touch with anything but a pickle fork or something like it. There are some great ceramic fiber builds here by guys like Fishbonz and Tobho Mott. Make sure to check out their threads before installing yours. They may change your plans a bit.

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  14. Douglas Braun

    Douglas Braun Copper

    Thanks Jeff, I was really stressing over what type of wire to go with. Even considered using two rings (screen tubes) with spacers between. I have screen remnants available to me in almost every size and or thickness, plus I have a roller for rolling it into tubes if it is too thick. Never even considered expansion contraction... my cylinder starts out at 16" minus 4" for wool brings it to 12" across... Was shooting for 10 but will settle for nine if you think it makes any difference at all. Satanite seems to be popular and not too spendy ($65ish' shipped) Was kind of curious how far you think 20# will go? If those are 5 pound bags in the video, than IMHO, it seems to appear to go quite far.

    Been thinking about this alot Jason. I bought a couple crucibles off amazon. Bear with me, I didn't know what I was buying... :( This one and this one. Then I took them to work and tried to build some tools for them. Realizing now I might want to trim the bottom off and add a remnant of sheet metal and casters like yours... The tools I built are stainless just because that's what I had. The tool for the smaller crucible has a horizontal at one end of a rod and a vertical welded to the other end. hoping this works. (YES THAT IS A DEAD FLY IN MY CRUCIBLE :D)

    72695394_2383356315264745_3414375605909585920_n.jpg 72599355_625434034649681_9189807520271564800_n.jpg 71970575_535040297067916_3438589244249997312_n.jpg 72813395_926282504412663_3674071984578232320_n.jpg

    The tools for the larger crucible are obviously unfinished. Probably going to add another bend to the lifting tongs so they grip naturally harder the heavier the load. all 3/16th 316l SS sheered off a remnant plate @ about 1.25" wide. Thinking of adding a little hook to go over the top while pouring. I added a dab of weld to the pivot screws to keep them from coming loose.

    72195458_526345348193507_5761837788819357696_n.jpg 72274902_1583657601777446_4502216441742753792_n.jpg 72385253_399715464036220_7823745476166942720_n.jpg
    Any ideas or constructive criticism are appreciated. Please remember I know nothing at this point so... I apologize in advance for all the ??? and thank you for all the help. Sincerely.​
    Last edited: Oct 10, 2019
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  15. Jason

    Jason Gold Banner Member

    Think inside furnace floor, bottom of tuyere about an inch above that... Add another inch or two for the tuyere, Then a 4 inch tall plinth. Then add your tallest crucible. Add about 5inches above that and that is the ceiling to your furnace. The logic is if a crucible breaks, it wont flood into your burner through the tuyere. Next thing, plinth is high enough to keep crucible out of the path of the flame. You only need 4-5 inches from the top of the crucible to the ceiling. Your 4" exhaust hole is good. This will make your furnace efficient and wont have to lower stuff in it so far like I do. Mine is every bit of 6inches too tall. Got a melt tomorrow, I'll measure it then.
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  16. Jason

    Jason Gold Banner Member

    Look close at mine. The bottom ring was removed from the body of my tank and welded to the bottom. Kinda hard to balance on a curved end. Here is another photo.


    see the problem? That is a number 10.
    Okay, maybe I'm only 2inches too tall.


    Another lesson.. Do NoT do what I did here with steel to hold in the refractory.
    It's done pretty good, but it's time to rework this issue.

    Last edited: Oct 10, 2019
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  17. Jason

    Jason Gold Banner Member

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  18. Petee716

    Petee716 Silver Banner Member

    Your tools look well made. The combo lifting pouring tool is cool. I'm a little concerned about the lifting end fitting in the furnace to catch the crucible. Also, things can get too hot to handle pretty quickly but I think you'll be ok when you switch it around to pour.
    A couple things you might want to check on the bigger pouring shank is your ability to keep the crucible held tightly when its fully loaded and whilst you're pouring with it. Even with adequate holding force the twisting action can be pretty awkward. Try some dry runs with your crucible full of sand to approximate the weight and do your testing at around the actual height you will be pouring at so you can get the real feel of it. Put some padding underneath in case your crucible drops out!

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  19. FishbonzWV

    FishbonzWV Silver Banner Member

    Hi Douglas, good looking shell you have.
    You haven't mentioned what type of fuel you are going to be using. This, along with crucible size, dictates how much room you need for the bore ID. If you have excess bore the furnace efficiency will be reduced. If you are using free oil I guess it won't matter but with propane it will.
    Your lid is very deep. It looks like it will take 3 layers of wool to get it flush with the body. An easy way to attach the wool to the lid is to tack about 6 pieces of 1/4" all-thread in a circle, push the wool over them and then weave tig wire around them in a circle. The 2" wool is very stable gravity wise and will be fine once it's covered with Satanite (two coats max on the lid). You can see the 'pleats' on my lid in the Satanite video. I used multiple layers of 1/2" wool so that is why I wove to the outside of the lid.
    Your furnace should only take about 15 pounds. Two coats on the lid, shoot for three coats on the body. The first coat goes on thin.
  20. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    The tools look well made. If you have a lift out furnace, I'm not sure what you would use the side gripping tongs for. For the open ring shank, do you have enough radial clearance in your furnace to insert the vertical end around the crucible? Stainless is nice and a relatively poor conductor but I suspect it will get pretty hot for anything except maybe aluminum service if you expect to flip it around and handle the same end you just used to extracted the crucible.

    I use open ring shanks too but my furnace is lift off so I snatch and pour with the same tool. I have open ring shanks for my A4, A10, and A20. I also have an A60 but that thing is a beast and a whole different matter. I used the open ring shanks without incident for several years but more recently added top clamps to them. The only time I really value the top clamp is when I'm emptying the crucible and becomes tipped well past horizontal. If you're not careful, it can fall out in that orientation but with the clamp you can turn it upside down and shake it about.

    A10 open ring shank

    15 Open Ring Shank.jpg

    A10 with top clamp added.

    A-10 Shank  Clamp.JPG A-10 Shank Clamp Open.JPG

    A20 with top clamp. I can bolt this one and my A60 onto my pouring cart, but in aluminum, I freehand everything up to A20.

    8 A20 Shank Clamp on Cart.jpg

    Last edited: Oct 11, 2019
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