Anyone have a source for Alloys Silicon in particular

Discussion in 'General foundry chat' started by HT1, Dec 30, 2020.

  1. HT1

    HT1 Gold Banner Member

    I priced master alloys on Belmont and amost feinted Aluminum Silicon and Cu Silicon are outragious



    Any Help??

    Thanks in advance

    V/r HT1
     
  2. Zapins

    Zapins Gold

    3.10 to 4.10 per lb at lancaster foundry supply in lancaster PA. Shipping is approx $15 for (3x16 pound ingots). They sell brass and aluminum too. No aluminum bronze tho.
     
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  3. Jammer

    Jammer Silver Banner Member

    Do you mean a master alloy, 50/50 AlSi? Silicon has gone up in price, $16 per pound in e-bay. I suppose because of solar panels to save the world. I was calculating what it would cost to make some virgin Everdur. Just to buy the copper, Silicon and Manganese would be $9.30 per pound. Cheaper to buy from Lancaster... for now. I know your not an Everdur fan but it's what I've had luck with.
     
  4. Zapins

    Zapins Gold

    Alloying your own stuff eats your crucible up due to the silicon metal. When you add it it becomes super corrosive until it mixes thoroughly. It will rapidly eat your crucible. Not worth it imo
     
    Last edited: Dec 30, 2020
  5. HT1

    HT1 Gold Banner Member

  6. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    When I bought my last load of A356 ingot, I also bought Strontium and TiB master alloys. I have a large supply of that if you need any but those modifiers and refiners are only useful with Al/Si alloys. I was going to buy Al/Si waffle too but didn't because I didn't think I'd use it. When I was talking to the supplier about it, he told me I'd find trying to get chunk Si into solution to be a real PITA and the waffle, being already alloyed 50/50, goes almost immediately. I seem to recall everything was available in 44lb boxes. It was a lot more reasonable than you were mentioning. What are you up to that you want to add Si?

    Best,
    Kelly
     
    HT1 likes this.
  7. Car pistons can use a "Hypereutectic" alloy with 16-19% silicon content to get strength below that of forged pistons. Car engines get around the problem of the silicon crystallizing with age as the piston gets a bit of heat treating with normal use. A customer had a 30 year old aluminium casting re-made as the original had been made from recycled pistons (at the same foundry by the same person who recognized it). He'd dropped the casting onto a concrete floor by accident and it broke into several pieces like pottery with large fern-like silicon crystals that formed in the high silicon piston alloy.

    No idea how you'd identify the right pistons without testing several makes and models with an X-ray gun. 4032 aluminium is 12% silicon, so if you can buy an ingot from somewhere that would let you get up to 12% silicon alloys. I read somewhere that during WW2, Ford company had problems with excess silicon in their bomber engine castings that was traced back to remelting runners with sand still attached: the aluminium was chemically converting the sand into silicon and forming excess aluminium oxide: silicon dioxide + aluminium => silicon + aluminium oxide.
     
    Last edited: Dec 31, 2020
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  8. HT1

    HT1 Gold Banner Member



    I have access to alot of 6063 if I could kick the Si up to 6-7 % I could cast it I have several new items that will be aluminum
    [​IMG]
     
    Tobho Mott likes this.
  9. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I'd generally say trying to use wrought alloys for casting is a waste of time, especially for parts that are only a pound or so because the difference in cost between free metal and nice casting metal isn't much. IIRC, the Al/Si waffle was about $3/lb, but x44lbs plus shipping, and keep in mind only 1/2 the lbs in the waffle are Si. If the parts needed strength or machining it would just further reinforce using a decent known alloy.

    But since these are ornamental, that's not much of a consideration, though I suspect you may want it to polish well.

    As mentioned earlier, cast automotive pistons are (relatively) high Si content, though in pistons it's for wear characteristics more than fluidity when casting. I think it's easy to tell a cast piston from a forged one. Problem is, you don't really know the metallurgy of what you are getting but at best, the Si content is going to be in the 7-19% range. To have the desired affect on the 6063, I'd think you'd want to get it into the 5-7% Si range. You won't do that on the low end and even with a 19% Si you'd need almost as much Pistonium as 6063, so unless you have a source of free pistons, you'll be buying half your metal anyway. At that point why not just use or buy scrap castings?

    Also, I have used pistons as casting stock for few ornamental parts where I needed high fluidity. I'd say they produced marginally better casting results but were much more grey in color and did not machine nor polish well.

    Still, some folks here seem to have acceptable results casting with wrought alloys. -Your results may vary. All this is why I just buy ingot.

    Best,
    Kelly
     
    HT1 likes this.
  10. HT1

    HT1 Gold Banner Member


    Thank you kelly,
    always good info, I already Bought some Technical Si. so I'm going to try mixing it with Flux, and adding it to 6063, pour a test mold of just 6063, and then with added Si to see WTF ,
    if it does not work, I'll sell the scrap, and buy ingot when I reach that point. then we will all have that much more info

    V/r HT1
     
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  11. crazybillybob

    crazybillybob Silver Banner Member

    I picked up some Silicon a while ago on Fleabay. I did it because I was gifted a bunch of aluminum extrusion. Adding a few % of it to the molten Aluminum made it shrink less and flow better. I'm going to guess it machines better now but the only thing I have done to the castings has been drilling.... I couldn't really tell with 2 x 1/4" holes. My Crucible doesn't look any worse for wear after 4 melts with Silicon added.

    I'm also going to say. What I cast was not life saving or supporting. It was all decretive.
     

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