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Thread: Novice Casting Questions

  1. #11
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    Quote Originally Posted by Petee716 View Post
    I've seen flour used as an additive to the sand in small proportions but not using it as parting (till now). I use a commercial parting that I overbought several years ago but I understand white chalkline chalk works well.
    High melt temp, length of time spent molten, and furnace atmosphere can all contribute to your porosity. A tight furnace would help you to control those variables. You could consider degassing as well, but it looks like you've gone to the trouble of making sand and tools, so you might as well complete a furnace.
    Welcome to the forum!

    Pete
    Thanks for the welcome!

    I thought I got the "wheat flour" from CW Ammen's book. I was surprised but thought I'd try it. I may have misunderstood. I've seen recommendations against talcum powder but with no explanation. I'll go back to talcum powder - I keep it around to lubricate tubes in tires anyway. So far I've been unsuccessful finding reasonably priced foundry supplies. For instance, I can buy a ton of green sand pretty reasonably, but one bag is hard to come by.

    Interesting comment you made on furnace atmosphere. Ammen recommended a slightly oxidizing atmosphere and I think my furnace gets enough flow into it to burn neutrally and bleed through all the cracks. Also read about letting the metal heat a few minutes in the crucible. I did that on the second pour but not on the first. I'll try to pour about as soon as I can next time. Thanks for all the comments, guys! I'm not giving up!

  2. #12
    Hi oldironfarmer, I'm new to this to, kinda learning as I go, but learning is a little slow sometimes..
    On my first casting, the sand turned black, I used some baby powder for parting but not sure what caused the burnt look.
    I scraped most of it out(didnt want to mess up my pretty sand) and threw it away, the rest that was left there I mixed
    in the pile on a tarp, wet it a little, covered it, walked on it a few times to break up the chucks, the next day mixed alittle more
    and it all looks like new again. So must have done something right.

    I keep my sand in a big tub covered with plastic and use a big 4" paint/Sheetrock mud mixer to mix it just before use..

    Sorry, alot more info than you wanted, sometimes I dont know when to stop..

    Anyway, I just finished a wheel for a belt grinder I building, I use to have a lathe but ex-wife wanted it.

    Will need to post it because I'm not 100% sure how to cast it and sure dont want to chop it into pieces if not needed.

    Good luck, and your casting looks pretty good.

    C

  3. #13
    Senior Member Tobho Mott's Avatar
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    Quote Originally Posted by oldironfarmer View Post
    I have seen the recommendation to not melt cans, and I have been collecting castings to melt. But what is wrong with melting cans? All I have read is they make a lot of slag. But they are free and I am practicing...
    Nice job, you're off to a great start!

    I only ever melted cans once, just to see if it is as bad as everyone says... Ugh, yup, what a slog; never again. But that is just me and many others here - if it works for you, that's great. If it ain't broke, as they say.

    Nobody ever got talked down from melting beverage cans that I can recall anyhow, no matter how rational the argument against it may have been. It seems to be the type of thing people can only discover for themselves. (Many of us here have gone through that. Once you eventually try melting and casting with good cast scrap and see the difference for yourself, I promise you won't ever want to go back to turning hard work into free dross, hot tears (rhymes with stairs not beers, though you may shed a few hot rhymes-with-beers tears as well), and shrinkage defects. ) So instead of trying to talk you out of it, I'll mention the good aspects of can-melting:

    First, it's not all as bad as people make out - you'll definitely get some good practise diagnosing casting defects and skimming dross, for one thing.

    You'll also have plenty of motivation to melt and cast some diet salt flux ingots, which you can learn how to do here with just a little searching; a fun DIY project.

    If you only use the can metal to try casting fairly simple shapes without too many changes in thickness or sharp corners, you might just continue to do fairly well with it.

    Perhaps best of all, I'd suggest saving some of your can (or extrusion - generally comes in thicker pieces thus is less drossy) metal ingots for later, in case you ever want to try alloying your own aluminum bronze or zamak, which do not require the use of good quality casting alloys like Wheelium (the stuff most car wheels are said to be made of, ie. alloy 356). Or you may one day wish to dilute the higher silicon content in aluminum alloys used to make certain parts (was it pistonite? Can't recall, someone please confirm if possible) by adding a few beer can ingots to the melt in order to bring its proportions and properties closer to something like wheelium, which does have silicon but in smaller amounts). I started out by breaking up and melting an old ladder to get into casting with; I haven't melted a ladderite ingot in 3 about years, basically since the day I picked up my first scrap alloy car wheels. So I have been saving the rest of my leftover ladder ingots for a while now.

    Now that I have experienced having to pay retail for some "real" aluminum bronze to cast with... Heck yeah I want to try alloying my own. Sounds like a lot of fun anyhow; being a huge money saver is just gravy. And because I still have my remaining ladderite stashed away somewhere, I won't have to use up my good casting aluminum to do it...

    Keep posting your progress and your pictures, we love that kind of stuff around here!

    And by the way, welcome to the forum.


    Jeff
    Last edited by Tobho Mott; 03-10-2017 at 06:26 PM.
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  4. #14
    Moderator DavidF's Avatar
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    Ive taken and added about half a pound of beer can ingot to 2 lbs of 356 ingot and made a really nice casting alloy....No idea what the alloy is now, but it casts and machines very nice.
    A calm sea does not make a skilled sailor....

  5. #15
    i process a lot of scrap into ingots for sale, this is what i have found as i processed and had the recycle yard that i buy from scan the finished ingots.

    Wheelium: 356 alloy with the the silicon on the higher end 7-8 %

    automotive cylinder heads, intake manifolds etc: 356 alloy with the silicon on the lower end 4 -6% it also tends to have a higher Fe content because of the iron that can't be removed prior to pooling the molten aluminum. I remove all shafting as soon as it will breakout of the aluminum but bolts valve components are racked out of the pool so some of it does get dissolved in. I can maintain it less then 1% Fe

    Pistons: these can be all over the place form 10 to 20% silicon mag etc in different quantities, they make good castings but i don't use them because of the inconsistency for a ingot for someone else to use. Much of my return business on the ingots is because I try very hard to keep the end product consistent,

    cans: are almost pure aluminum and generate a casting that doesn't machine good due to its stickiness. It also has a higher surface tension and doesn't flow as well.

    extrusions are similar to the cans

    Hope this helps a little
    Art b

  6. #16
    Senior Member machinemaker's Avatar
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    Can bodies are a usually close to 3004 and the tops are 5182. I guess that I never did the math to figure what alloy would be close when melted together.
    kent
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    There is beauty, power and excitement in simple old technology!

  7. #17
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    Quote Originally Posted by Tobho Mott View Post
    Nice job, you're off to a great start!

    I only ever melted cans once, just to see if it is as bad as everyone says... Ugh, yup, what a slog; never again. But that is just me and many others here - if it works for you, that's great. If it ain't broke, as they say.

    Nobody ever got talked down from melting beverage cans that I can recall anyhow, no matter how rational the argument against it may have been. It seems to be the type of thing people can only discover for themselves. (Many of us here have gone through that. Once you eventually try melting and casting with good cast scrap and see the difference for yourself, I promise you won't ever want to go back to turning hard work into free dross, hot tears (rhymes with stairs not beers, though you may shed a few hot rhymes-with-beers tears as well), and shrinkage defects. ) So instead of trying to talk you out of it, I'll mention the good aspects of can-melting:

    First, it's not all as bad as people make out - you'll definitely get some good practise diagnosing casting defects and skimming dross, for one thing.

    You'll also have plenty of motivation to melt and cast some diet salt flux ingots, which you can learn how to do here with just a little searching; a fun DIY project.

    If you only use the can metal to try casting fairly simple shapes without too many changes in thickness or sharp corners, you might just continue to do fairly well with it.

    Perhaps best of all, I'd suggest saving some of your can (or extrusion - generally comes in thicker pieces thus is less drossy) metal ingots for later, in case you ever want to try alloying your own aluminum bronze or zamak, which do not require the use of good quality casting alloys like Wheelium (the stuff most car wheels are said to be made of, ie. alloy 356). Or you may one day wish to dilute the higher silicon content in aluminum alloys used to make certain parts (was it pistonite? Can't recall, someone please confirm if possible) by adding a few beer can ingots to the melt in order to bring its proportions and properties closer to something like wheelium, which does have silicon but in smaller amounts). I started out by breaking up and melting an old ladder to get into casting with; I haven't melted a ladderite ingot in 3 about years, basically since the day I picked up my first scrap alloy car wheels. So I have been saving the rest of my leftover ladder ingots for a while now.

    Now that I have experienced having to pay retail for some "real" aluminum bronze to cast with... Heck yeah I want to try alloying my own. Sounds like a lot of fun anyhow; being a huge money saver is just gravy. And because I still have my remaining ladderite stashed away somewhere, I won't have to use up my good casting aluminum to do it...

    Keep posting your progress and your pictures, we love that kind of stuff around here!

    And by the way, welcome to the forum.


    Jeff
    Thanks for the welcome! A lot of good experience here!! I have the promise of two aluminum truck wheels so I'm assuming they will be alloy 356 as well. I hope. I like the material names, gave me a good laugh. I guess a lot of the dross from cans is the internal coating. Thanks for your insight!

    Quote Originally Posted by DavidF View Post
    Ive taken and added about half a pound of beer can ingot to 2 lbs of 356 ingot and made a really nice casting alloy....No idea what the alloy is now, but it casts and machines very nice.
    I had thought I would mix ingots, but I was thinking 50/50. Sounds like that may be too much. I really like your water outlets, great work!! It's alittle tough to machine the cans, low feed high speed seemed to work on the can casting. Thanks for commenting.

    Quote Originally Posted by master53yoda View Post
    i process a lot of scrap into ingots for sale, this is what i have found as i processed and had the recycle yard that i buy from scan the finished ingots.

    Wheelium: 356 alloy with the the silicon on the higher end 7-8 %

    automotive cylinder heads, intake manifolds etc: 356 alloy with the silicon on the lower end 4 -6% it also tends to have a higher Fe content because of the iron that can't be removed prior to pooling the molten aluminum. I remove all shafting as soon as it will breakout of the aluminum but bolts valve components are racked out of the pool so some of it does get dissolved in. I can maintain it less then 1% Fe

    Pistons: these can be all over the place form 10 to 20% silicon mag etc in different quantities, they make good castings but i don't use them because of the inconsistency for a ingot for someone else to use. Much of my return business on the ingots is because I try very hard to keep the end product consistent,

    cans: are almost pure aluminum and generate a casting that doesn't machine good due to its stickiness. It also has a higher surface tension and doesn't flow as well.

    extrusions are similar to the cans

    Hope this helps a little
    Art b
    Thanks for the detailed information. A friend gave me some dragster pistons and rods. They look forged. Any idea what alloy they might be? If they are cast they are exceptional. Interesting the scrap yard can measure silicon. Can they measure other elements as well? I may have to get acquainted with my local yard. They've already told me they don't sell scrap brass/bronze.

    Is there an easy way to add silicon, or is there other necessary alloying agents as well?

    The can material is tough to get a smooth machined surface.

    Thanks again for all the information!

    Quote Originally Posted by corky View Post
    Hi oldironfarmer, I'm new to this to, kinda learning as I go, but learning is a little slow sometimes..
    On my first casting, the sand turned black, I used some baby powder for parting but not sure what caused the burnt look.
    I scraped most of it out(didnt want to mess up my pretty sand) and threw it away, the rest that was left there I mixed
    in the pile on a tarp, wet it a little, covered it, walked on it a few times to break up the chucks, the next day mixed alittle more
    and it all looks like new again. So must have done something right.

    I keep my sand in a big tub covered with plastic and use a big 4" paint/Sheetrock mud mixer to mix it just before use..

    Sorry, alot more info than you wanted, sometimes I dont know when to stop..

    Anyway, I just finished a wheel for a belt grinder I building, I use to have a lathe but ex-wife wanted it.

    Will need to post it because I'm not 100% sure how to cast it and sure dont want to chop it into pieces if not needed.

    Good luck, and your casting looks pretty good.

    C
    Thanks for commenting. I'm back to baby powder on my next casting. Can't be too much information.

    Quote Originally Posted by machinemaker View Post
    Can bodies are a usually close to 3004 and the tops are 5182. I guess that I never did the math to figure what alloy would be close when melted together.
    kent
    They are similar alloys anyway, aren't they? Thanks for the comment.

  8. #18
    Moderator DavidF's Avatar
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    Those dragster rods are likely 7075..... One awesome alloy, but not the greatest for casting.
    A calm sea does not make a skilled sailor....

  9. #19
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    I put a spout on my crucible today. It's 4" sch 40 304 SS. I had been using it without a spout and had a little trouble getting the pour started. From what I've read tonight it is probably the can alloy high surface tension holding it back. But I like the looks of the spout.

    IMG_1005.jpg

    I want to make some v-belt sheaves so I made a simple pattern today.

    IMG_1006.jpg

    It's pretty clunky but with enough machining should make a sheave. Made the wheel separate so I can cast the hub with a bigger wheel if all works out.

    IMG_1007.jpg

    Pattern is turned from black walnut. I think it is the best wood I have for patterns. It sure turns nice!

  10. #20
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    7075, that's some stuff! 60,000 psi yield is pretty impressive. No silicon, sounds like it needs to be blended with a higher silicon alloy.

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