Something different for a change - casting lead

Discussion in 'General foundry chat' started by Guster, Aug 20, 2019.

  1. Guster

    Guster Silver

    Friend asked if I can cast an RC sailboat keel bulb for him. He had a 3D model and I've done a few of these in the past. Mostly lost wax in plaster but this gave me an opportunity to mess around with 3D printed patterns and use the kiln in anger. The 3D model was a mess but I got it into Fusion360 and manipulated enough to make a split pattern of the keel bulb.
    Plan is to clean these up and use them to make a plaster split mold. Next - a good coat of filler primer and a little sanding.
  2. Jason

    Jason Gold Banner Member

    That will be cool. Soft, but cool. Maybe he can give it a fiberglass layer on the outside.
  3. oldironfarmer

    oldironfarmer Silver

    OK, I'm confused. Casting lead. Are there thespians here somewhere, and a casting couch?

    Looking good, Guster.
  4. Guster

    Guster Silver

    A lot cooler... lead melts safely in a pot over a gas stove. I like to get a good finish out of the mold and then just a good coat with an epoxy paint. A softer marine urethane is not bad either as the bulbs tend to get a bit bashed. These boats tend to not spend enough time in the water for urethane to be affected.

    Missed the casting call again Andy. We were looking for a good character cast too! :D

    Lead is darn expensive these days! Managed to intercept a bucket of wheel balancing weights as long as I bring their bucket back. o_O
  5. oldironfarmer

    oldironfarmer Silver

    Are your weights mostly lead? About 25% of ours are magnetic. Then some are zinc. Wish you lived closer I've got old batteries and lots of lead.
  6. Al2O3

    Al2O3 Administrator Staff Member Banner Member

  7. Guster

    Guster Silver

    These are the old ones with the metal clip. The looked pretty soft in that I could ding the surface with my thumbnail. A little antimony is not a bad thing as it makes the lead a bit harder wearing. I have another source who sells it by the 5kg block for a good price but he is away visiting overseas for a bit.

    I do have some lead flashing and a few pieces of lead pipe(actual lead pipe) along with another keel bulb or two. Probably more lead scrap than brass actually.

    I've used some before and the rusted metal clips and surrounding tarnished metal does create some extra dross. They are not free here anymore which is what surprised me when I was offered the bucket(half full) and that he wanted his bucket back - as in more value in the bucket. He runs a pretty clean shop and has other containers for the newer adhesive style weights. I'll only need about a cup full for this project.

    I'd like to make a lead shot dripper to make some shot for a shot bag for sheet metal work. Since lead is frowned upon for use in shotguns now it is harder to get hold of well priced shot.
  8. Jason

    Jason Gold Banner Member

    The stuff is getting harder every day to source. I've got a rentawheel shop that is all too happy to give me all I can haul away. Only thing, only about 20% is lead. Makes for a seriously nasty job
    to clean up, sort and separate. When I did the legs of my anvil, it took me hours to remove the cigarette butts, and broken glass mess. Now I'm about to be staring down the barrel again with this glass lead nightmare stupid me signed up for.:rolleyes: I always start with a magnet, because a lot of them are steel. Then a shop knife sorts the zinc from the lead. It's a tediously nasty job.
    Good luck, if I only needed 2lbs, I'd buy the crap on ebay in a heartbeat.
    best 20bucks you'll ever spend.
  9. Guster

    Guster Silver

    I should really post you a screenshot of what that amounts to in shipping cost to NZ. But I know what you mean and yes, I have a couple of those locally with some decent prices. Otherwise this bucket is tidy with none of that extra stuff donated. It will get more serious if I end up having to cast more.

    For now I'm treating it as a one-of favour. More will come at a cost. :D
  10. Jason

    Jason Gold Banner Member

    That's one thing I miss about AA. I can't keep track where all you guys live all over the world. It was handy having a location under your AV. Oh well, the photo storage makes up for it.
  11. rocco

    rocco Silver

    For those of you looking for lead in the U.S., lead is still commonly used in stock cars. Every car class has a minimum weight specification and the cars are often built under weight with lead ballast added to bring the cars up to specs. So, head off to your local track and talk to some people, it won't take you long to find some lead.
  12. Tobho Mott

    Tobho Mott Silver Banner Member

    Cool project!

    Jason, if you click on someone's avatar pic, the location from their profile will pop up, along with some other info.

    Jason likes this.
  13. Guster

    Guster Silver

    Sometime during the previous week I picked up some filler primer and slapped some on the keel bulb prints. Gave them a sand down till the printed material just started showing which is good enough. Found this scrap of acrylic which gave me a great idea to make a match plate since I can visually align the halves when I glue them to both sides.

    Friend I'm casting this for also found some clean lead, enough to cast two of these saving me needing to sort through the wheel weights for now.
  14. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Make sure you clamp the cope and drag together and better yet, do so with boards to support the backside of the sand. Much easier to float the cope or breach the mold with the increased pressure from the dense metal.

  15. Guster

    Guster Silver

    Definitely planning on clamping the plaster mold halves together. On smaller ones I just use a rubber band but thiss one I'll use two quick clamps.
  16. Guster

    Guster Silver

    Finally had a little time to myself to do some fun stuff again. :rolleyes:

    So last time I was making the match plate which then sat in my workshop for a few months. Even lost it for a while as I was tidying up. The found it just after Christmas. Made some basic wooden flasks. Secured the match plate to it after liberal application of petroleum jelly and cast some plaster, one side at a time. Deflasked the plaster and dried them in the oven for a bit. Sprue was simply drilled with the molds clamped together. Next day I preheated them to around 100C before adding the locating pins clamping between wooden planks and pouring some lead.

    Got two nice casts out of them before the plaster surface in the mold started to spall. Included the basic matchplate in the photo I'd forgotten to take before. The keel slot was never going to reproduce nicely in the mold so I just milled it on the milling machine. Since the recipient only wanted one he was more than delighted for two.

    In the process I also couldn't find my lead casting pot so I quickly whipped up something out of scrap stainless. Get'er done.
    OMM likes this.

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