Homemade crucible tongs

Here is some shots of my home made crucible tools. Looks like a good thread to collect these kinds of photos.

Pouring tool with sliding lock.







Adjustable bolt prevents crushing the hot crucible.

 

Daja Vu

#6 > Crucible Utensils

 

Pictures being what they are that tend to disappear.... This thread will be helpful to the new comer looking for some ideas to duplicate.

 

Jason, i couldn't agree more. Excellent reference for what actually works.

 

The only problem I see with that pouring cart is that it appears to be fixed as far as tilting it, which means you may be pouring from up too high, as there is no vertical movement (if I am seeing it correctly).

A pivot point at the top of the vertical support shaft would solve the problem.

 

I think I need to make a larger diameter plinth so my tongs will bottom out in the furnace at the proper height instead of having the hinge plates hitting the rim of the crucible when I lower the tongs in.

Pete

 

Here's some photos of a crucible gripper I'll be copying for my home foundry. It's designed in such a way that the heavier the load, the tighter the grip will be. There is a layer of insulating material between the steel discs at the top of the unit which helps shield the heat as it pulls the crucible out of the furnace. I'll probably modify the design with a skirt/rim of insulating material to further shield your gloved hand from radiant heat as you remove the crucible. It get used to pull A20 crucibles with 30 Kg of of bronze or brass.

 

I dont understand yet how that thing articulates... but a heat shield isn't a bad idea. As long as I dont have to play peek a boo around it. I need to see the landing pad that I set the crucible down on.

 

Hi Jason, there is a hardened steel pivot (roll pin) at the top left of both photos, just above the heat shield that allows it to open up. In use the ring on top allows a gloved finger to to hold it open as the side grippers go into position beside the crucible to grip it. The small steel bar pivot on the top handle is a clamp lock that prevents the thing from opening and dropping the crucible.

In use, you have your steel pouring handle (steel ring on one end sized for the crucible) lying on the concrete with an old truck piston sitting in it's steel ring. The crucible gets lifted out of the furnace to rest on the piston. The piston has a 1/2" of loose silica sand on top of it to give a cushion for the rough base of the crucible to sit on. You then lift the pouring handle and the crucible with it and pour your metal.

 

That's a pretty cool setup I hadn't seen yet. Build one and take a video of it in use for us.

 

Here you go Jason....around the 1:56 mark you can see it being used. Sorry for the poor camera angle, I wasn't going to get in the way .

 

Holy sheep balls batman. That wasn't what I envisioned at all. I have to reach inside my kiln to pull the pre heated shells and that's only at 1700 degrees. It's the worst part of pouring ceramic shell.
No way in hell would I want to reach inside my tall furnace to pull a pot of bronze out. The radiant heat of digging inside my kiln goes through the backs of even my chrome fireman's gloves! The problem I see with this setup is once you lift, your committed until that thing is on the ground in the pouring tool. A bigger shield will help if it extends up to your shoulder. The radiant heat off the sides of the furnace will be just as hot as coming off the top of crucible.

I need to make some kind of go go gadget extendo arms to pluck my shells. I've been wrapping my hands in kaowool and that does work, but it's STILL friggen hot!

 

Kelly, it was thrown away after that pour, we were using a whole lot of junk: a mix of bronze and mostly corroded scrap brass so he didn't want to cross contaminate his good crucible with anything like phosphorous. I'm told one bit of phosphorous bronze in a pot will contaminate later pours and make the bronze porous. We don't normally get so much metal over the floor as we did that day, although that mould design tends to have that effect due to it's design. Another old silicon carbide crucible went soft and the side could be moved inwards when used to that point, very disconcerting to see, it also got tossed at that point.

Jason: Yes the side of the furnace is hot and you do have to work quickly against the radiant heat, one of those expensive silver gloves helps but don't last very long. I'm told white asbestos gloves are the absolute best but there's no way I'm ever going to go near that stuff. I've had all sorts of discussions with two foundry owners about more remote ways of lifting a crucible out: many people have tried all sorts of things over the years that work, but have some disadvantages. The main issue is the pot cooling, if you have a crucible of A20 and smaller, there is a danger of the bronze cooling too fast to get a good casting. A30 and larger have adequate thermal mass to let you take your time with a pour.

David: These guys were the first to use no bake resin in Australia, back in the day according to the resin company rep who flew out to train them to use it. In those days it was easy and so convenient that he got out of using green sand completely. Personally I love the speed and the advantages but it's getting harder to find.

 

I really like that rotary table.
Nice melt and pour demonstration.

One thing I noticed on some of the crucible tongs is that the top part may grip the crucible before the bottom part.
It should be the other way around, with the upper fingers making light or no contact when the lower fingers fully contact the crucible.

The upper fingers are basically to guide the crucible, not to grip it, and Morgan recommends not gripping or lifting a crucible from the top.

 

What? You mean to tell me those "professionals" on youtube using a pair of water pump pliers grabbing them by the rim is WRONG??? lmao

 

It seems like I saw "you know who" using channel locks on a crucible one time, but I will not mention names since I may not remember that correctly.
Luckily I can say that I have never used pliers to lift a crucible, but I have a bumper crop of other dumb stuff I have done, so it balances out I guess.
I have gotten more safety conscience with every passing day.

It is sad, but I watch casting videos on YT for entertainment just to see how dumb and dangerous people can be, but I cringe at the safety aspects of many videos.
The videos from foreign countries are the worst (generally but not always; some of the locals more than hold their own in that department), with people pouring iron with short sleeve shirts, shorts and open sandals, no eye protection of any kind, no dust masks for anything. Yikes !

 

Even the pros can be guilty of such things, one foundryman I know who had been casting since the 1940's, preferred sandals. He told me that brass and bronze hit the skin and fall right off due to sweat forming a steam layer (Leidenfrost effect) whereas aluminium "sticks like jam". Another has used blacksmith tongs to lift a new SiC crucible out after discovering it was a slightly different diameter and the crucible lifter couldn't grip it.

 

After much 3D printing with the stick welder, angle grinder and blowtorch, I have my crucible gripper close to being finished. All I need now is a circular heat shield above the crucible and maybe something to shield the handle from radiant heat.