Octopus sculpture

Discussion in 'Lost wax casting' started by Zapins, Dec 18, 2018.

  1. Zapins

    Zapins Gold

    Hmm. Sounds scary. I've got some I could try it, but I'd imagine that it would etch or discolor the metal too?
     
  2. Jason

    Jason Gold

    Don't know... Test piece. Ya know we can do this stuff over the phone right? lmao.:D
     
  3. Zapins

    Zapins Gold

    Yeah true would be fun.

    Do I just dunk it in 99% HCl or do I dilute the stuff?
     
  4. Jason

    Jason Gold

    Start with 50/50. I'll go look in my comments section. It was in one of my videos. brb.
     
  5. Jason

    Jason Gold

    Found it.. The guy mentioned HF acid and not muriatic acid. F THAT! Wonder if he was yanking my chain. No sane person screws with that! Look down in the comments on this one.

     
  6. Yes hydrofluoric is used in foundries to remove silicates from bronze, it exposes a beautiful crystalline structure in the metal too. Not sure of the concentration though, to dispose of the exhausted acid, it's neutralized with caustic soda to get large sodium fluoride crystals forming overnight in water. You also have to keep syrettes of calcium gluconate as the antidote to inject if any is spilled on your skin. I think once the concentration of hydrofluoric is below 20% it's not immediately lethal: aluminium wheel cleaner is 10-15% hydrofluoric and I've heard of people who washed their aluminium truck trays complaining of sore fingers and arms after liberal use of the stuff without gloves.

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    acid dip.jpg
     
    Last edited: Jun 6, 2019
  7. Jason

    Jason Gold

    Soooooo maybe try wheel cleaner? The guy on my channel said mix it 20:1.
     
  8. I'll have to ask what concentration he uses, wheel cleaner may be a cocktail of other stuff too. This article says even 5-10% is highly dangerous: https://engineering.tufts.edu/microfab/documents/SOP_OxideEtch-BHF.pdf

    Being exposed to the stuff doesn't mean you'll feel a burning sensation on exposure and if the fluoride ions get in your bloodstream it's also poisonous as well as acid's corrosiveness.
     
    Last edited: Jun 6, 2019
  9. Zapins

    Zapins Gold

    Yeah I think I'll steer clear of that stuff. Sounds like a good way to get hurt.

    Speaking of hurts. I got my first burn from molten metal. I was loading the half full crucible with bits of scrap and one of the pieces splashed and ejected a single droplet of metal and guess where it went? Straight down the half inch space between my glove and my hand. Of course I got it off as soon as I felt it but it was still enough to get me a little 2nd degree burn. Should heal up ok though.

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  10. Tobho Mott

    Tobho Mott Gold Banner Member

  11. Zapins

    Zapins Gold

    A lot of clean up still to do but here is a sneak peek. If I can ever get this crap cleaned up from all the spruing. I'm wondering how I'm going to buff this thing up once welded into position, the legs go at weird angles and it's too heavy and awkward to use my bench grinder. Hmm. 20190606_145725.jpg 20190606_145613.jpg
     
    Mark's castings and Jason like this.
  12. Jason

    Jason Gold

    It's going to be tough to access between the legs to clean up the welding. One leg at a time and you can get most of it with the least amount of ass pain as you work across them. Please tell me you're not going high buff on this? Once this thing hits the salt air, it will go green in a month no matter what you do to it. Light LoS, some clear coat spray crap in a can and walk away. Great detail on the suckers, he's looking really good... How's the weight?
     
  13. Zapins

    Zapins Gold

    Was thinking high polish, with brass lacquer to seal it.

    Weight is still tough to tell. Body is about 17 to 18 lbs and tentacles look about 4 lbs, but I haven't tigged it together or cut the sprues off yet. So I'm not sure. That would make it about 50 lbs which seems quite light compared with what I had thought.
     
  14. Zapins

    Zapins Gold

    Everything was cut off from the sprues, sand blasted and ground for welding. Took all day.

    Will be tig welding, sandblasting and finishing the surface tomorrow. I'll polish to a gloss later in a few weeks time.

    20190607_001741.jpg
     
    oldironfarmer likes this.
  15. Jason

    Jason Gold

    Those arms arent THAT bad... Only a couple are pretty close together. When ya do one of those, finish the grinding before moving on. You'll be fine.
     
  16. Zapins

    Zapins Gold

    I'll have to tig them in place using the wheel to avoid spacing issues. I dont think I can get a complete weld all the way through the leg. I'm pretty sure the center of the leg wont be fused with the body. Only the outer 1/4" oh well
     
  17. Jason

    Jason Gold

    That's plenty. The only way you can get really deep is to Vee it out and lay on the bronze. The pipe guys call this root and cover pass I guess. He's not structural, he should be fine. How are they going to attached it to the wheel? Hopefully they will drill through the spokes into his legs and body, make a mark, then drill and tap his ass. That's how I'd attach it. He cannot come off that wheel
     
  18. Zapins

    Zapins Gold

    Yeah that's what I was thinking they'd have to do but since I'm rubbish with tapping and threading I'll let them do that. It shouldn't come off the wheel even without those bolts but it will surely rattle and move around as the wheel is turned. Better to bolt it in place.
     
  19. Zapins

    Zapins Gold

    Welding up octo.

    About to start on legs when the body cools enough to manipulate.

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