my first pour, a miserable failure.

Discussion in 'Castings, finishing/ repair/ and patina's' started by Miles Lowry, Aug 20, 2020.

  1. Miles Lowry

    Miles Lowry Copper

    I have improved since my first attempt. I tried to pour copper into standard muffin tins. The copper melted through the tins and spread across the concrete popping and spitting as it spread out. 20200612_001626.jpg
     
  2. Jason

    Jason Gold

    Whoops....
     
  3. Petee716

    Petee716 Gold Banner Member

    No, no, you've got it all wrong. That's a frog.
    Muffin tins and dog food cans are good for aluminum and that's it. Even if your metal is cool enough to not burn through the metal the steel will braze to the melt and you'll have to peel it off or turn it off on a lathe. I've had to do both. And I've had burn-throughs just like you've shown above. I had 3 cans filled and subsequently drained befor I realized what was happening and ended up using a needle scaler to get all of the embedded limestone out of a 10 lb bronze cow pie. Even thick steel ingot trays will hang on unless there is a good coating of iron oxide and your weld seams are reasonably smooth. The first time I used my ingot trays I ended up drilling and tapping the ingots for 1/4-20 bolts, heating the ingots up one at a time to redhot in a forge and levering them out. Now, after I've preheated them and let them cool a bit, I spread a layer of petrobond in the weld seams of the molds. Works a treat.
    Just a word about the (potential) Teflon on your ingot trays. Burning that stuff will make birds literally fall from the sky. Best grind as much as you can off before using it. I'm no safety weenie, but it's nasty.

    Pete
     
  4. Miles Lowry

    Miles Lowry Copper

    yeah well I've learned my lesson, from now on all metal muffins will come from cast iron muffin tins
     
  5. Tobho Mott

    Tobho Mott Administrator Staff Member Banner Member

    What are your plans for the ingots? If you plan to do sand casting, you can make ingot molds with the same molding sand if you want. I just flip my baking pan (much like your muffin mold except the 8 mini loafs variety) upside down inside a one sided wooden flask I built for it and use the pan as a sort of matchplate pattern for ramming up ingot molds. Usually I can dump any loose greensand out with the ingots and reuse the mold 2 or 3 times before the ingots start getting real lumpy looking.

    Jeff
     
    dtsh likes this.
  6. Jason

    Jason Gold

    If you weld, stick some flat steel on the ends of some 2" Angle iron and pour in those. Much safer than dollar store muffin tins.
     
  7. Miles Lowry

    Miles Lowry Copper

    I'm going to try a skull, i have a foam skull left over from last year. I'm going to attempt resin sand because the clay isn't readily available. Even the clumping cat litter isn't using the clay anymore.
     
  8. Jason

    Jason Gold

    lol... Here we go!
     
  9. Miles Lowry

    Miles Lowry Copper

    I'm guessing that this is a hot button issue?
     
  10. We've just seen a lot of guys take the same path. I'm getting my popcorn ready.

    I do make sand molds for brass ingots. When the brass brazes to a steel mold it's a good fit.

    Tobho Mott is a skull maker too.

    Cheap cat litter from Dollar General is still bentonite. Or grab some motor oil and make petrobond (not for me).
     
  11. You also may have good success with any local sand which also has a little clay in it. Just learn to do a clump test.

    Worst come to worse I'll send you some bentonite.
     
  12. Miles Lowry

    Miles Lowry Copper

    I got some from dollar tree but it doesn't say what the ingredients are.
     
  13. metallab

    metallab Silver

    Indeed, good idea, I have exactly the same.
    But dry it thoroughly before pouring any metal in it, otherwise any moisture (usually within rust on the steel) will splash metal out ! Usually I dry it above the vent hole of the furnace in two steps to vover the entire length (mine is 70cm == 28") and check with an infrared pyrometer gun that the temperature of the bar is well above 100 C.
     
  14. Jason

    Jason Gold

    I think the skull thing is because most of us aren't soy boy eating beta males. We are men that drink beer, F women and cast skulls. We like our music loud! We are risk takers, do dangerous shit and aren't afraid to get dirty or suffer a few cuts and burns along the way.

    So get outside, scratch your balls, crack a brew and pour yourself an entire GRAVEYARD of skulls! Rock on!
     
    Jim Edgeworth likes this.
  15. Tobho Mott

    Tobho Mott Administrator Staff Member Banner Member

    You can just use plain clean dry sand to cast skulls using lost foam casting. Stick a 4" long 1x1 foam sprue on the underside of the skull with a hot glue gun, bury it in a bucket of sand with just the top of the sprue exposed, vibrating the sand to help it compact and fill in undercuts like the eyes, shove an empty soup can with both ends cut off 2" down into the sand around it, then top up the sand outside the can. If it is a large skull you should try to hollow it out first to save metal and avoid shrinkage defects, but for the sorta baseball sized foam skulls it's not needed. Not for cast aluminum anyhow. You pour the metal into the can fast enough that the sprue stays submerged until it's full. Sometimes it tries to trick you into thinking it's full before it is, so if you stop pouring, stay in position ready to resume until you're sure the can isn't going to suddenly drain out and let you watch the top of the mold collapse. For the best finish, coat the foam skull in a thin layer of watered down drywall 'mud' and be sure to let it dry fully before you cast it.

    Casting foam skulls is how I taught myself how to do lost foam casting, it took a fair bit of trial and error before I could be pretty sure it was going to work every time (at least with cast aluminum... Bronze has proven to be a little trickier), but the small skulls are pretty easy going. I know some people think they're kind of silly, but hey, this way you don't have to learn how to carve styrofoam at the same time you are trying to nail down a reliable process, so to me it's an ok way to jump right in and make some kinda cool little castings quick and easy that you can set out on your front step on halloween or whatever while you figure out how it all works. I still have a big bag of foam skulls I hoarded years ago, so every now and then I'll pour another one just for tits and pickles.

    Here's an example, 2 successful pours and one sand float defect to show what can happen when you either don't vibrate your bucket enough or you overfill the soup can. It's much harder to get sand float with aluminum than bronze though...



    The hollow sprues shown in the still shots from an earlier video aren't particularly helpful, I'd skip doing that. A simple 1" square solid foam sprue works fine for me almost every time.

    That is my quick n dirty lost foam process. Definitely check out Kelly's (Al2O3's) lost foam method too, to see what can be accomplished with a more professional setup.

    Good luck and happy skullcasting! :D

    Jeff
     
    Redwolf947, Jason and oldironfarmer like this.
  16. You need some assertiveness training, Jason. Quit letting people push you around. Try to come out of your shell and approach issues directly instead of walking behind an umbrella with some weirdo beating on a drum to keep you motivated. Learn a little self motivation for a change. You're just too much of a follower...
     
  17. Jason

    Jason Gold

    lol Andy. Is that what it is?
     
  18. Miles Lowry

    Miles Lowry Copper

    What's the deal with the can? What's the purpose?
     
  19. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    It creates a buffer to help maintain a continuous pour. The draw from a lost foam cast is not uniform.

    Best,
    Kelly
     
  20. Tobho Mott

    Tobho Mott Administrator Staff Member Banner Member

    Yup, it's so that you fill up a tall narrow reservoir directly above the sprue waiting to help fill up the mold, instead of having all that metal spread out across the top of the bucket where it just sits there.

    Edit - be prepared to have no idea how full the can is due to all the fire and smoke coming up out of the can. It stinks. Then it stinks again even worse when you dump out the bucket to get your casting out.

    Jeff
     

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