First attempt at crucible tool

Discussion in 'Foundry tools and flasks' started by Stephen Robson, Feb 25, 2021.

  1. Decided to try to make a tool today to lift crucible in and out of furnace. All comments and suggestions welcome. IMG_20210225_154653.jpg
  2. Keep in mind that the crucible tongs can get quite hot, glowing even, so the steel in contact with the crucible can soften and loose strength. This is nothing that suitable material thickness and design can't overcome, that gripper looks to be about 1/8" or 3mm thick steel around the crucible area so heat soak is going to be a potential issue. I made mine out of 12mm/ 0.5" square steel bar so the core is still reasonably stiff as steel isn't very thermally conductive. I know of a gripper made from 1/2" square hollow bar which needs to be used in under a minute to get the crucible out or the grip begins to loosen.
    Last edited: Feb 25, 2021
    Jason likes this.
  3. Zapins

    Zapins Gold Banner Member

    My tools are approx 1/4" thick and seem to be ok. 1/8 might be a tad thin but nothing a few extra support welds couldn't fix.

    1/2"?? Good God you must be buff to lift those tongs and crucible haha.
  4. Well considering it's for a AT-30 and A-25 crucibles, I'd say they're about right for the weight it has to lift;):


    lifter heat shield 3.jpg
    Last edited: Feb 25, 2021
  5. Zapins

    Zapins Gold Banner Member

    Ahhh I see :)
  6. The ergonomics of the longer style gripper tongs would see you trying to hold a larger crucible with arms extended at head height and the yellow hot crucible held with a somewhat springy grip about level with your wedding tackle :eek::oops:.
  7. Thank you for your comments. The maximum size crucible I will be lifting is an A6 and I will certainly be mindful of the heat build up. IMG_20210225_151545.jpg
  8. Jason

    Jason Gold

    This is when I was building mine. The stuff touching the crucible is 1/4" and the square bar is 1/2" One issue I see is your ability to keep a wide squeeze going is what keeps you from dropping this thing. Not really the best solution. It works better if you can get the reins close together and control the severity of the grip with a stopping bolt or design of the closing mechanism.
    I can run mine with one hand (I don't, but it's possible) I can squeeze my reigns in a vice and they still wont crush the crucible because of a simple stop bolt.

    This is an A6. I built an identical setup for my A10.


    See who close the handles are to each other?

    The bolt sets the tightness the crucible is gripped. It should be supported but not capable of being squashed. They get soft when they are full of bronze and could be squashed.
    Last edited: Feb 25, 2021
    dennis likes this.
  9. Also I noticed your handles don't cross over similar to a pair of pliers, so you'll have to exert some outwards arm force on the handles to grip the crucible, it's easier with closed handles close together and parallel so you can grab both handles individually with both hands at different points along the handle length to get tipping leverage when pouring. I could be wrong but I think humans have more strength closing their arms than when spreading their arms.

    This guy's lifting tongs (0:53 mark) can be held closed with one hand and gripped in two places:

    Last edited: Feb 26, 2021
    Jason likes this.
  10. bill

    bill Silver

    I used this one for about six months.


    Wasted a lot of welding gloves until I purchased fireproof gloves....

    Made this one day.

    IMG_3051.jpeg IMG_3049.jpeg

    One handed if needed. but that is rare. Like never that I recall.
    Jason likes this.
  11. Jason

    Jason Gold

    That's the video I was looking for! I had to twist my ass off to get the crucible unstuck from the plinth. It was my very first pour and you can see me yell FK when I realized I forgot the cardboard. :oops: Fortunately it didnt cost me a brand new A6. lol, live and learn, I got lucky!;)
  12. dtsh

    dtsh Silver

    My lift/pour shank also looks a tad anemic, but it's held up quite well. If memory serves my crucibles are an A8 and A10, or was it A10 and A12, either way not terribly large. Made out of square tubing and the parts that sit alongside the crucible have a V bend to add strength.
  13. bill

    bill Silver

    Jason...what is flashing up under the crucible? Is that the cardboard you mention? What is the cardboard used for?
  14. Jason

    Jason Gold

    Yeah, it's just cardboard to keep it from sticking. Probably not necessary outside the furnace, but why take any chances?
    Plus it looks cool and makes a great thumbnail photo for yt.:D:rolleyes:
  15. garyhlucas

    garyhlucas Silver

    14C8815A-E4A5-41F8-A1D4-020E2EE32F9E.jpeg 23FCA424-6398-4725-BBAE-06C2CC810ED9.jpeg

    I’ve posted this before but it actually works very well.
    Bldr J and Mark's castings like this.
  16. rocco

    rocco Silver

    That's pretty slick Gary!:)
  17. oldironfarmer

    oldironfarmer Silver Banner Member

    I think they are plenty heavy but I agree you might like crossing the reins so you can squeeze. I've not found a stop to be necessary. You might want the reins to be a bit shorter, too, depending on how tall you are. If you cast brass a pot full of hot brass can pucker you up trying to make sure you don't release the hold on the crucible.
    Jason likes this.
  18. Tobho Mott

    Tobho Mott Gold Banner Member

    Having to spread the reins apart to tighten the grip would take me some getting used to. For my #6 crucibles I use a cheap and easy single off-the-shelf 3 finger fireplace log grabber tool for liftout and pouring, though I do set it down to switch grips.

    This one isn't mine, but it's similar.
    View attachment 9664

    This one's mine.
    View attachment 9665
    View attachment 9666

    I would not think it would be safe to use for lifting a bigger crucible, but I've never felt like I didn't have full control of a #6 ising it this way.

  19. bill

    bill Silver

    How do you use it in the furnace? Under the crucible? For the same purpose I suppose...
  20. Jason

    Jason Gold

    yup. Before you light this party, drop a couple of cardboard pieces on the plinth, load up the crucible with metal and park it on top of the cardboard. Lite the wick and do the work. When finished, I shut the furnace down, drop a couple more pieces of cardboard and return the cleaned out crucible quickly onto the burning cardboard. Remove the burner and close the lid. Allowing it to cool slowly overnight will prolong the life of your crucible.
    Last edited: Feb 26, 2021

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