Melting Furnace lining question

Blacksmithing | Casting | Fabrication | Steel | | |

Hello everyone; I have not posted in awhile. I am interested in knowing more about ferrous melting in a furnace.
To jump to the question, I am thinking of putting together a smallish iron melter, some call it a cupola. Besides fire brick for the insides, I wonder what the molten metal pool area, at the bottom is made with. Since a mold is used to pour molten metal into, can it be used as a liner or melt bottom for a furnace?

I am familiar with safety issues and hot metal in general. :)

I hope someone has gone this route before me and can spare me the effort of experimenting or perhaps send me a link where I can read further on the specifics.

Many thanks


visitor's picture

you want to use a high

you want to use a high density castable refractory that is rated for 3000 degrees with a relativly high alumina content call Harbison Walker and tell them what type of iron you intend to melt, be it grey ductile etc they should be able to ship you a few 100 pound bags of what you need.on a side note you should also get 2in.thick, high density fiberwool to back this chamber up with, maybe two boxes of 150X24X2. but i am just an aarrteeest in a stooopidio so dont take my word for it. i cant believe i actually replied to a thread here.

gwynlaredogranger's picture

ugh, fine.

you want to get 3000 degree high density high alumina castable refractory , backed with 2x24x150 rolls of high density ceramic fiber wool,backed with your brick which should be 2800 degree range Hard Bricks. they also sell cupola blocks , you shoudl call Harbison Walker refractories and get them to ship you a pallet of castable, block etc, 3000 degree range mortar wouldnt hurt either.i cant believe i just posted here.good luck with your cupola, post melts.i am assuming you have the rest figured out.but dont take my word for it, i am just an arteeest in a stuuuupidio.

keithh's picture

HI gwynlaredogranger

Hi; Thanks for your response. I'm in Canada and I have fairly local suppliers, 4 hours drive one way, but they dont want to do small orders. I was referred to a distributor who wants to hit me with extra charges that the main manufacturer wanted to they are not artist friendly.
Even though I may end up going the route you supplied and I do appreciate your taking teh time to reply,
I am in the short, searching for rammable. It might be more problematic in the long term but at least I can source it without paying crazy charges like, 3 times the cost of the material I need just to break a new skid when when said distributor uses same product for in house products. Wow..
I guess they are telling me they do not need my business.
So, castable it is. I will see if Harbison Wlaker has a dist in Canada.
Many thanks dude, you the best..

visitor's picture

refractory distrubtor

Hi, call Industrial Consulting and Supply West- a refractory distributor- at 713-675-4800 they are artist friendly- they will break pallets and only look to make an honest percentage. Good luck

ksquare's picture

Keith, I wanted to build a

Keith, I wanted to build a cupola myself. You may want to check and see if you can find a supply of coke ( or however you spell it ). I stop short of building one since I couldnt find a supply of it. I dont think that coal will even get hot enough to melt iron in a cupola. If you do find a source Let me know. I hear that its the cheapest way to melt.

Good luck

visitor's picture

Re coke

HI ; Thanks for your email. While taking blacksmithing courses, we made our own coke by burning off the coal tar etc. around the fire.

Just a thought. Anyways, so far, the supplier I contacted says coke is hard for them to get as the factory that burns coal etc sends them a freight car of coke at a time, but not on a regular basis.

In Canada, we are paying $20.00 per 50 lbs. and a bit less if you take over 200 lbs.

I will keep in mind however..

Cheers Keith

Rich Waugh's picture

Ksquare, Coal will get hot


Coal will get hot enough to melt iron in a cupola, as will charcoal (real charcoal from wood, not Kingsford briquettes). Coke is nothing but coal with the volatiles driven off by heating, either during the process of burning the coal such as when forging or in a retort where the aim is simply to make coke. Coke has the advantage of not producing smoke the way that coal does before it is coked.

Basically, to produce for heat for forging, casting, smelting, etc, we are burning carbon in one form or another. Coal, coke, charcoal are all carbon. In fact, when we burn propane or natural gas we are burning hydrocarbons which are just another form of carbon.

Carbon, whether coal, coke or charcoal, (and many hydrocarbons) yields roughly 14,000 Btus per pound. The temperature at which it burns in determined mostly by whether it is burning with air or oxygen.

That's all a bit of an over-simplification bu tit's accurate enough for our purposes.


GujaratFerroAlloys's picture

Keith, I believe everybody


I believe everybody here has already answered what you needed answered. Although I do have a question for you, what do you mould with and how do you mould?

We are a commercial foundry and we use silica sand with resin and catalyst as binder, earlier we used sodium silicate and Co2, but with No-Bake product quality is much better. Why I am saying this is because you cannot use moulding material as a refractory because once sand is heated to that high a temperature the binder will not hold the sand together anymore, which is what it is meant to do for easy knockout and cleaning of the finished product.

Devansh Jhaveri
Gujarat Ferro Alloys (P) Ltd.

keithh's picture

HI Deansh

Thanks for your reply. I did finally locate a distributor for Morgans-Thermal ceramics high heat castable in Canada, and only 5 hours away. Took some time but there it is, persistence paid off.

I have not built the cupola yet due to materials problems and funding, which seems to be in short supply lol

With no cupola the sand casting has not got off the ground either. :) The supplier I have lined up, and I, have not met to discuss my needs yet. Perhaps this fall?

My wife and I are almost finished with this years hay crop so once that is done and all the equipment is cleaned and readied for storage I should have a clear sailing until next spring, sorta. Operating a farm is a job unto itself it seems.

Well, thanks to everyone for your responses. I will do my best top keep everyone updated and post pics when this project see more life at my end.

All the best


Ankur G's picture

Question regarding binder

Is there any kind of resin commercially available which can work in these high temperature process