Casting a Shackle, My First Try at Iron

Discussion in 'Sand Casting' started by oldironfarmer, Mar 18, 2019.

  1. OK, I got tired of watching everybody cast iron like it was easy.

    I've got literally tons of old cast iron laying around so I broke a piece off this engine. It was already ventilated.

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    And cut up an old manifold from a Farmall M tractor

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    Found an ancient shackle to copy

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    I was in a hurry as usual so I plugged the holes with plaster of paris and built up the worn areas.

    Made a sand mold

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    Got it hot in 45 minutes. It was warming when I realized my leaf blower has two speeds, I always just used low, but I switched it to "Iron" and added a little oil.



    Since this was my first time I used a big sprue and runner. She said bigger is better.

    IMG_5349.JPG

    Maybe an inlet riser? Is this air, slag, or moisture from the sand?

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    It drilled like a dream.

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    Now I've got the pair I've always dreamed of...

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    Here's the bad side.

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    There's three holes, in the wrong place, but it is still serviceable.

    All in all I was pleased.
     
  2. Melterskelter

    Melterskelter Gold Banner Member

    I think your sprue and runner are way way too large. And I think your shackle yoke froze and then shrinkage started in the sprue and runner and in the pin bosses. The pin bosses plus runner end together froze last. They acted as a riser and made the demanded donation.

    So, use a runner 1/4 “ thick and 1/2” wide. Put a 1.5 diameter by 2” tall blind runner 1/2” away from the gate between the sprue and part. The riser will freeze last and keep the runner hot enough long enough to feed the shackle pin bosses.

    I recently poured a 40 pound str edge with a 1/4 x 1” runner and the sprue was maybe 1/2” to 5/8”. Prior to that I was using a runner 3/4 wide and 5/8 high. Those pics of old and new runners etc are in my mousetrap / plug lifter thread. I was “sure” the new runner would be too small. Nope.

    Finish looks good by the way. Used coal powder in the sand? Prolly could use a little more. I like 6%.

    BTW, I am not certain of any of the above analysis but I think it’s true.

    Denis

    Added: this was grey iron for a shackle? Ductile might be better for that application as you probably know. I’d worry about poor tensile strength of grey and its propensity for fracture.

    Added added: That was a 3 second pour.
     
    Last edited: Mar 18, 2019
  3. DavidF

    DavidF Administrator Staff Member Banner Member

    Im not 100% on what the defect is, but agree with Dennis on the gating. You would be surprised how small a gate iron can flow through and still fill a mold... Melt looked pretty clean when you poured.. Can only get better from here :cool::cool:
    Welcome to the world of iron!! You know a little JB weld, some bailing wire, and a spritz of wd/40 that engine could have been running this weekend ;)o_Oo_O:rolleyes: LOL
     
  4. PatJ

    PatJ Silver

    That is a great first iron pour Andy.
    Way to go ! :D

    Ditto about the ductile iron thing melter mentioned.
    My guess on the defects: Entrained air bubbles.
    Your pour speed was a bit uneven.

    I use the lowest speed setting on my leaf blower, and it actually works better than the higher settings.
    I tune for a little under 3 gal/hr of diesel.

    Another iron club member. :)
    All things considered, a great iron effort, and some nice hot iron.

    Edit:
    You could have made it look a little more difficult to make us feel better about all our struggles with iron.

    .
     
    Last edited: Mar 19, 2019
  5. Thanks for the advice. I knew the runner was probably too big, but I had it on the shelf and, of course, was in a hurry.

    So your take on it is shrink damage which is different than it shows up on aluminum? I could see that if the iron was freezing and a liquid spot between was sucked out.

    I'll make some 1/4"x1/2" runners. I should have put in a blind riser, I would have for aluminum. But I would have put it in to collect gasses and slag. I've been watching your threads, but didn't know the dimensions on your runners.

    I have held off trying cast iron because of the seal coal issue. I've got lots of coal powder but don't know how it would affect aluminum and brass/bronze/aluminum bronze which I need to be able to cast with the same sand. I guess I could get a metal bucket I could seal and put seal coal in it. This was just the eBay sand I've been using with no additives.

    Since ductile iron was only discovered in 1943 I'm sure this original shackle was grey iron so I wanted to be true to the original design. Or I didn't even think about the type of iron used. I need to find out how to identify ductile iron. Lots of parts on old tractors are cast steel. I was sure the manifold would be grey iron, along with the block. I ground tested a wheel clamp (which is subject to structural load and impact) and was seeing some secondary explosions. I need to get a steering arm which I'm sure is cast steel and see how it sparks. I'm guessing drilling ductile would not roll up such nice little chips.

    I've been pushing the limit of aluminum gates and have no fear of small gates. I was surprised the mold filled, so here we go!!

    Thanks for the good words, it was pretty much fun.

    A riser to take care of shrinkage would help with air bubbles, I assume, so I may never know.

    I can't remember your furnace. My furnace is pretty big inside (55 gal drum with one layer of wool and two layers of bricks) and I was eager:oops: Fuel is practically free, I think you're burning diesel? I keep the flames just licking out the flue and I have a five inch flue so I can skim before I open the furnace. On low I had my air damper wide open and on "Iron" I had it almost closed with just a bit more oil. I have no idea how many gallons per hour I'm running. I used a lot of oil yesterday with an aluminum melt, the iron, and two copper scrap melts.

    Beginners' luck. I'm expecting a string of failures in this most difficult of crafts.:)
     
    Tobho Mott likes this.
  6. DavidF

    DavidF Administrator Staff Member Banner Member

    Guessing at the defect on the bottom of the shackle, Maybe a blow from the greensand being a bit too damp??
     
  7. Melterskelter

    Melterskelter Gold Banner Member

    I am not certain, of course, about the shrinkage issue. But in its defense as the culprit, that metal had to shrink as it cooled. This is a "chunky" part as opposed to a flat thinnish part like a plaque or trivet. In a flat part the two opposing surfaces can simply come 1% closer together as the part cools and who’s the wiser. But, in a chunky part/runner/sprue complex a surface has to fail. (A vacuum defect can also occur). The question is only which surface. So, by putting in a riser you provide easy pickins for collapse where you want it.

    Shrinkage does vary some from batch to batch for reasons that are not evident to me.

    But I have never regretted a riser placed to accommodate feeding the area last to freeze. I have regretted a lack of riser too many times to recall.

    I think moisture would show usually up as many many surface deep dimples and maybe a blow as well.

    I can see your coal dilemma. I don’t know if it would adversely affect aluminum. Time for a small-scale trial:) Perhaps you will end up with two sand boxes...

    Denis
     
  8. I was worried they might be from moisture. Since I got my muller I've been running my sand too dry. It packs in my hand but the ramming tool just stirs it. This sand was a little more moist.:( But not wet. The defects were on the top and sprue end.

    I'm all aboard with a riser!:D

    Two sand boxes, that's what I need. Jason already picks at me for playing in a sand box.:p
     
  9. Tobho Mott

    Tobho Mott Gold Banner Member

    I have about 1% "seal" coal (bituminous coal dust, but not found on any beach) in my sand and it does fine with aluminum. Castings shake out clean as can be, nice and shiny.

    SealCoal.jpg

    Jeff
     
  10. PatJ

    PatJ Silver

    That would be "sea coal", as in coal that washes up on the beaches from undersea deposits.

    .
     
  11. DavidF

    DavidF Administrator Staff Member Banner Member

    no, its coal seal... Just place one on top of the mold before pouring for good luck...
    seal coal.jpg
     
    nwcf_1, _Jason and oldironfarmer like this.
  12. PatJ

    PatJ Silver

    Gray iron will break cleanly with a sledge hammer.
    Ductile iron and malleable iron I think will just bend, but not break like gray iron.

    Gray iron castings are not considered for structural use.
    They do make good machine bases and such due to their vibration damping and wear characteristics.

    .
     
  13. Melterskelter

    Melterskelter Gold Banner Member

    Just to add that I did use term coal powder but the "sea coal" I use was purchased at a foundry supply and is not dust by any means. Dust or powder might work "fine" so to speak but the product I bought is ground about like pepper from a common pepper grinder. One theoretical reason coarser may be desirable is that it is less likely to impede sand porosity. But that is pure speculation on my part. Other reasons commercial foundries might prefer it a little coarser could be related to easier handling with fewer clouds of black dirty, potentially explosive dust in the air.

    Denis
     
    Last edited: Mar 19, 2019
  14. Good points. Seal coal was a typo, but thanks for ridiculing me.:p I do flap my arms like a seal when my gloves get too hot. By the way that is a thermodynamically appropriate way to cool your gloves.

    I've got about a half ton of coal in my blacksmith shop, not low sulfur, but that should not get into the casting. Does everybody agree 6% is still OK with aluminum and copper alloys?

    If ductile iron pipe is ductile iron it breaks pretty much like other cast iron.

    So, are small steam engines made from ductile iron? I imagine Melterskelter is using grey iron.

    One more question, if you remelt ductile iron, will you lose the magnesium and have grey iron?
     
  15. DavidF

    DavidF Administrator Staff Member Banner Member

    Yes, goes back to grey iron...
     
  16. PatJ

    PatJ Silver

    According to the iron book, ductile iron is not really considered structural, so I guess that is why a pipe cracks? Not sure really.

    Some of the steam engines I have made have been cast in Class 40 gray iron, purchased in bar stock and labeled as such.
    Other steam engine parts have been cast using motor end bell scrap, which breaks cleanly with a sledge hammer, but I have never tested the composition.

    .
     
  17. ESC

    ESC Silver Banner Member

    Congratulations. You're on your way now.
    Print back with locksmiths graphite and it will serve to cushion the iron against the sand. Used this way it doesn't affect the bulk of the petrobond I mold with. I also use it to dust the gates and runners of aluminum castings and smooth it in with a slick or oval. I think it helps the flow and it seem to improve the surface finish .
    As HT1 mentioned, cast iron has different rules.
     
  18. Tobho Mott

    Tobho Mott Gold Banner Member

    No ridicule intended; I thought you were borrowing that term from me - check out my greensand-making posts from last summer, I've been calling it seal coal all along to differentiate it from actual sea coal. (Also it goes nicely with my "whale" oil burner.) The coal I used isn't exactly fine powder or anything either, it's stuff a local blacksmith sold me a shopping bag of for $5, and probably a little coarser on average than the sand grains. Cured my bronze castings from burnt on sand.

    Jeff
     
  19. Melterskelter

    Melterskelter Gold Banner Member

  20. I was making fun. I don't get offended easily. Even my Zumba teacher singles me out for ridicule during classes. It's great fun. I had not seen your use of "seal".


    I've got a gallon of graphite. Would dusting with graphite be in lieu of sea coal additive? I'm not sure what "print back" means. Dust with graphite then reinsert the pattern?

    So making ductile iron at home is likely unattainable. Chunking magnesium into a crucible sounds exciting, though.

    Sounds like my old tractor castings are the way for me to go. I'm thinking about making a steam engine, and brass and grey iron do go well together.
     

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