custom or home made crucibles

I've gone and a bought a small kiln to try melting some lower temp metals before I go for the big guns and make a propane fired furnace, it's a tiny little thing and I've calculated the largest commercially made crucible I can fit is A3 salamander. However, there is spare space without being in contact with the elements and I'm wondering if I can either
get one made to size that could hold a bit more or make it myself? Refractory in an old flowerpot? Make one from fired clay?

Would you all be able to post your links to where you get crucibles from and maybe there will be a design there that will work too

Also it's a front loading kiln and I'm not sure on the tongs/bearers I'll need, might need to make some - anyone else tried getting a crucible from a front loading furnace/kiln?

Any thoughts/links here would be helpful. Thanks

 

I get all my casting stuff here. Cheapest ive found in UK

https://specialplasters.co.uk/foundry-products/crucible-clay-graphite.html

 

heres the dimensions of their crucibles

https://specialplasters.co.uk/image...g?phpMyAdmin=4aab4fd41499c29080ccce9f9b94af6f

 

Thank you, I think based on this an A4 might also fit...bonus! have written to check on the weights with them, shall see what they say.

 

Why would the weight matter?

 

He ain't heavy...my 'Amazonian' crucibles fit sort of in between, interpolate as you see fit!

PS: all of these have been fired here at least once, the 120mm high one is the one I use the most as it fits best with the current plinth setup in my small top load propane furnace.

 

There is nothing to stop you from using a masonry cutting wheel in an angle grinder to cut a few inches off a larger crucible to get it to fit into a furnace. Also for lower melting point metals a steel crucible coated with ladle wash would be perfectly fine.

 

I meant weight of metal it holds - I assume it is the same as the artisan A4 but want to be sure as it is a slightly different shape I think.

 

Good point Mark, does that weaken it a bit though?

Not heard of ladlewash, what does this contain - borax?

 

Thanks Tops - is the weight for Aluminium?

 

Sorry to have misunderstood, weights above are dry fired crucible only. All-full volume of the 125mm tall crucible above is 490ml although I have yet to charge and handle anything at 100%...table below is weight of metal w/o crucible.


https://www.theworldmaterial.com/density-of-metals/
Marks's post reminded me of this implement, handle slides down dovetail to detach, want to say it was a gift for helping someone move or something like that:

 

I had the idea of using a grinder to modify a crucible suggested by a foundry supply company, as far as I know the good crucibles have the glaze vacuum impregnated throughout the crucible during manufacture (see the Morgan company videos on Youtube). So long as you were careful with your cutting it should be fine. I've also seen rings cut from crucibles used on small charcoal forges.

Ladle wash is some kind of proprietary ceramic slurry coated onto the steel ladle and dried out: http://smelko.com/?page_id=375

 

[QUOTE="Edit ok so I think in answer to my question above yes 1litre of one thing is the same as 1 litre of another thing by volume, but it is not the same by weight. According to this calculator
https://www.thecalculatorsite.com/conversions/substances/metal.php
1ltr bronze (sil) = approx 8.15 kg, does that sound right?[/QUOTE]

Edit on above: I tried messing with some 2,3,4 kg weights just to see what I can comfortably manipulate with 1-2 handed grip and I think 5-6kg is my limit anyway so I won't be messing with 7-8kg pots until I'm a bit more practiced/stronger and have that propane fired beauty.

All in good time... stick with A3 and cut down A4 for now, especially as the crucible, the shank and so on add extra weight.

 

wa your furnace look like? Perhaps you could cast a ring of refractory cement to increase the height of the furnace

 

Diamond coated blade used for masonry work.

 

I increased the height of my nasty little furnace, with a layer of fire bricks so that the crucible fitted. Cheap and easy solution,

Cheers Charlie

 

It's technically not a furnace in the traditional sense but a 'tabletop furnace' kiln. so can't be adjusted as you say, I actually have no idea if it will work it's just the start of my experimenting...

 

chazza you have a pic you could share?

 

agreed that would work but to get the A4 in I only need between 2-4mm off the top which is easier to grind than cut. I wonder if a belt sander on 40 grit or something could do it...

 

Thank you for the link and info, can't see what it's made of but I'll ask