Crucible with a Spout

Discussion in 'Foundry tools and flasks' started by oldironfarmer, Mar 16, 2019.

  1. oldironfarmer

    oldironfarmer Silver Banner Member

    OK, I had to try it. To minimize bifilm generation by using a spout to get the pouring point as close to the basin as possible I put a spout on my stainless steel crucible. It also allows drawing liquid from under the surface so dross is not drawn into the pouring basin. My crucible is old and leaks water through the wall (but not aluminum :D) so it needs to be replaced. I'm not losing much by drilling a hole in it.

    IMG_5303.JPG

    316 SS 1/4" pipe is all I could find (316 may be a little better here, 304H would be preferred) so I ground the end to fit and welded it on with E309 rod. That's a good rod for dissimilar metals and some guys recommend it for cast iron repair.

    IMG_5304.JPG

    I ran a drill down the spout to make an elliptical hole inside (and clean up my excess root bead:oops:) after this picture.

    IMG_5305.JPG

    Man that crucible is nasty. Kelly said it would be OK.:p Probably not.:D But with it leaking water I don't want to clean it too much or I may have to weld up the holes.:eek:

    Since I'm a novice and made my furnace too big I have plenty of room for the spout :cool:

    IMG_5312.JPG

    I'm doing a series of pours of the same pattern to learn what works and what does not. Right now I'm working out pouring basins and small sprues and runners. I'm down to 0.05 sq in runners. I tried to copy Perry's pouring basin but made it too shallow. I'm also putting runners and the gate in the drag with a blind riser at the pattern in the cope so I have a bit of a weir to deflect the flow as the metal comes into the blind riser.

    Anyway, on to the the results of the test.:eek:



    I'm tickled. It was amazing easy to keep the pouring spout entrance submerged in aluminum, and a very short drop into the pouring basin.

    Edit: Here's the casting. Runners less than 1/4".

    IMG_5309.JPG
     

    Attached Files:

    Last edited: Mar 16, 2019
  2. PatJ

    PatJ Silver Banner Member

    It looks like that worked pretty well.
    I think Morgan makes Crucibles with bottom-feed spouts, but you would have to be careful not to pick up any trash that may settle on the bottom.
    Nice controlled pour too.

    .
     
  3. Al Puddle

    Al Puddle Silver Banner Member

    Ok, I have to try it too.

    My variation is a one inch hole near the bottom.
    IMG_1656.jpg
    I wish I had taken a picture of the welder's first attempt at interpreting what I wanted. I'm still thinking about having them make it that way.
    This is what I had in mind.
    IMG_1670.jpg
    It passed the water leak check.
    I plan to heat the crucible up to bright red - orange and then let it cool down in the furnace before I use it.
    Any suggestions?
     
  4. PatJ

    PatJ Silver Banner Member

    Looks good.
    Go for it !

    .
     
  5. Al Puddle

    Al Puddle Silver Banner Member

    I sure would like a temp. data recorder. I've been thinking about setting up a video camera to watch the temp readout, where I can shout out when an event has occurred. Is there a gizmo that allows me to record K type thermocouple readings on my computer?
     
  6. oldironfarmer

    oldironfarmer Silver Banner Member

    That ought to work.

    The reason I used a pipe is to avoid the air contact with the metal in the spout, and it allows you to get the spout really close to the pouring basin. However it takes a big furnace to fit it in. Your spout looks great.

    Brim full on the crucible is lower now, you'll have to watch that.
     
  7. oldironfarmer

    oldironfarmer Silver Banner Member

    Search USB Thermocouple to see several variations under $100 for data loggers.
     
  8. Zapins

    Zapins Silver

    So, stainless is the best aluminum crucible material?

    Hmm. Why 304 instead of 316? I thought 316 was the better high temp metal.
     
  9. oldironfarmer

    oldironfarmer Silver Banner Member

    More properly stainless steel may be better than carbon steel for aluminum crucible use. Refractory crucibles are best, of course. I have not use carbon steel long term but is does oxidize and scale a lot at 1,500F.

    I used 304 because it was available and cheap. The pipe spout is 316 because that is what my electrical supply house had in stock.

    316 is better for about 100F higher temperatures than 304 so it is marginally better. Ratings are for a much longer life than we expect out of a crucible. My recollection is that 316 has greater high temperature creep resistance, and that's why we use it in refinery pressure parts. A crucible is very low stress. I think I got good life out of the 304. And I get it hot. It probably gets to 1,800F while melting aluminum to 1,600F. Plain carbon steel, on the other hand, is rated for 650F and it will melt aluminum just fine.

    I think my new crucible will be 316, because the guy who gave me the pipe thinks it is 316. I have 24" of it, so enough for four crucibles. The only plate I have for the bottom is 304 and that is what I'll use.

    My old crucible will leak water but I've figured out it will not leak aluminum. I think an oxide forms in the hole preventing aluminum from actually running out. I'm not much on cleaning my crucible between charges and am starting to realize the oxide layer in the crucible adds to longer life. I've also deduced the bottom of the crucible is bowing because the hard oxide and carbon layer in the bottom keeps growing and pushing it out.
     
  10. DavidF

    DavidF Administrator Staff Member Banner Member

    304 and 316 both may crack after repeated heating cycles (at least if under some sort of stress) I forget the technical name for it, but basically the matrix will crystallize.
    321 stainless might be the better choice ??
     
  11. oldironfarmer

    oldironfarmer Silver Banner Member

    I think you mean carbide precipitation. I think 321 SS will be quite expensive if you find it. My 304 crucible lasted so well (I think because it's basically unstressed as a crucible but even with carbide precipitation it's probably still stronger than a refractory crucible) I wouldn't bother with better metallurgy. When I finally give up on my first 304 crucible I may whack it with a hammer and see how easily it fractures.

    If you like 321 you might have a look at 347. It's a little better in the carbide forming range of 800F to 1,500F.
     
  12. garyhlucas

    garyhlucas Copper

    I was given some #10 graphite clay crucibles with bottom pour spouts. I guessing these will be good for pouring aluminum without dross? Would a lid on the crucible during heating help reduce dross creation?
     
  13. oldironfarmer

    oldironfarmer Silver Banner Member

    A bottom spout crucible should be great! Please post pictures.

    It seems like a lid would help. It really depends on how much oxygen is required to form the aluminum oxide. There may be plenty under a lid anyway. I don't know but I bet someone here does.
     
  14. garyhlucas

    garyhlucas Copper

    Here is a picture of the crucible. It gets the metal right from the very bottom.
     

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    _Jason likes this.

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