I want to make a forge using some stuff I already have. I'm totally new to all this. Can you make one thing that works well for blacksmithing and also gets hot enough to melt metals like copper, brass, or aluminum for casting? I would like to make something that will get hot enough to try to make damascus or forge stainless steel. It would be cool to make something that I can use inside to heat my workshop in the winter, but also roll it outside for summer time forging. I have 2 old roasting pans, and also 2 brake drums. I came up with an idea for a side blast forge with a 4 way split so air comes in both sides. A couple months ago I made a brick of DIY refractory cement from a recipe I found online, it was type s mortar and perlite. Seems pretty fire proof but I never gave it any real test. Then I came here and saw the warning to not use portland cement. Is perlite a good thing to use? Could I mix perlite and refractory mortar, like Mortaclay-40d to make something I can cast in forms? Here's the stuff I have and a basic plan I came up with. What would you do?

 

Welcome aboard Benson, glad to have you. I STRONGLY suggest you do some serious reading in the solid fuel forge section of this forum. You also need to ignore that people on the internet say about forges. Nothing you're shown is workable, at all. 

The refractory mix will not work at forging temps let alone temps suitable for bronze casting. Perlite melts around 2,000f and refractory mortars and cements are meant to stick fire brick together and will NOT survive flame contact in a forge. A fire pit sure but not a FORGE.

The semi wheel would make a nice firepit and if you connect a stove pipe above it would make a decent chimnea like fireplace for the yard. It won't work as a forge for two reasons, first you can't supply it with an air blast to generate forging heat and secondly it's so deep you'd never be able to heat more than the end of whatever bar you put in. 

Don't sweat it, we all had unworkable ideas when we broke into the craft, everybody does and in all crafts. That's perfectly normal, it's one way humans figure out how to do things or how things work, we experiment.

One of the things I love about hanging around this place is helping a newcomer to the craft avoid making the same old mistakes that have been made for the last couple thousand years. That's what we're doing when we say, "That won't work".

We'll help you figure out the basics, build up a good working kit so you can make new mistakes we can learn from. That's a whole lot less of a joke than it seems. We learn from our mistakes and believe me, we are a really well educated bunch. 

Please don't let me forget, I have a bad memory from an old injury. Just reply and we'll talk okay? Basic things like what you want to make, where you live, (desert ranch, apartment in a large city, etc) type of general stuff. 

Frosty The Lucky.

In the solid fuel section of the forum are several threads about JBOD forges.... Just a Box of Dirt.  And yes you have the materials to make one of those.

They work, several people use them regularly.  A JBOD can get you started while you figure out what kind of forge you REALLY want to build. I'm not sure I'd try to use it in a shop without good ventilation or a good chimney though.

I started playing at forging with a firepit in my back yard.  That "worked" but was difficult, then I went the easy route a bought a Mr. Volcano.  Unfortunately those don't seem to be available anymore.  

Good luck and I hope you get your "new" anvil put to work soon!

 

You're asking the wrong question. Instead of "How should I make a forge using some stuff I have?", the right question is "How should I make a forge?" If the stuff you have helps you with that, great. If not, save that stuff for something else. 

Your job right now is to focus on getting started forging steel, not on becoming a forge designer. I second Brian's suggestion that you look at a JABOD forge (the "A" is capitalized and included in the acronym), as this is a proven design that's quick and easy to build at very low cost.

One final thought: forges that heat metal for smithing and furnaces that melt metal for casting are two different things, and trying to make one setup that will work for both is not a good idea. Focus on one thing at a time, and you're more likely to have success.

No matter what kind of forge you use you will need good ventilation in a shop. Even a gasser will consume the oxygen in the shop quite quickly. Hence the suggestions to get CO2 detectors when using one. 

A gasser may heat the shop some, a solid fuel forge very, very little. The idea is to keep the heat IN the forge, not heat a room. People have been quite surprised that i have a fire hot enough to melt steel but still need a torpedo in the winter to heat my shop. 

Thanks for the tips, everyone. I won't try to make a forge that is also a foundry. That is definitely surprising that a forge wouldn't heat a shop.

I see that most people use fire clay mixed with sand for forge liners. Does this require any special firing process, or will using the forge fire the clay?

I'm also noticing that all of the solid fuel forges I've seen so far are like an open pit and don't have a top, and the gas ones do have a top, more like an oven. No need for a top with solid fuel?

Not sure where in the Adirondacks you are located, but you might consider getting some direct instruction and recommendations from the Adirondack branch of the New York Designers Blacksmith group.  Typically there are monthly meeting where you can interact in person with other smiths and even use tools and equipment that have already been proven.

Uh . . . no, MOST people do NOT use clay and sand as a forge liner unless you're talking about a solid fuel forge or the right type and shape. The "liner" in my cast iron Buffalo rivet forge is approx 1pt. clay to 2 pts sand. Just enough clay to make it compact hard when moist. If you're talking about a blower or bellows driven pan forge then garden soil will work. Only let it be damp enough to ram hard. If you make mud and smooth it around nicely it WILL crack as it dries (shrink check). Adding sand does a couple positive things. 1st. it allows moisture to exit easily so lighting a fire won't cause it to spall. The sand can move as the liner heats and cools so it's less likely to crack. (Heat Check)

A clayed forge pan does NOT want to be fired like pottery, that WILL cause it to break up. A forge fire makes a LOT of heat in a relatively small area so the center of the liner gets really HOT long before the liner a few inches away warms up too much to touch. If it was a rigid piece like fired pottery it can NOT heat at very different rates or the hotter expanded section WILL either crumble or split the cooler outer section.

I ram mine with a wooden mallet till it bounces, then take an old piece of burlap and burnish it smooth. The less dust and loose bits the fewer clinkers will form and the easier it is to rake coal and move pieces in the fire without scrubbing dust the liner. 

A propane forge is a closed Furnace and yes it needs to be enclosed though not sealed. There is whole section about nothing but gas forges and burners. A propane forge is an entirely different machine than a solid fuel forge.

And yes, they ARE machines with different mechanisms workings and characteristics in operation.

Frosty The Lucky.

 

 

Good Morning Benson,

I think you need to spend some time finding someone who can be a Mentor. There are quite a few different Blacksmith Associations in your part of the Continent, there is a list at the bottom of the Home Page. There also is a list on the ABANA web-site (Artist Blacksmith Association of North America). It is easy to sit at your keyboard and punch buttons, you need to work with someone who will show you how to work with a Hammer. You don't need to spend a lot of money to get started, you NEED to pay attention what others HERE are suggesting. Take little steps, Rome wasn't built in a Weekend. Purchase or borrow from your local Library, a reference book (there are many good books). 

Good Luck on your Journey.

Neil

Much of what I would say would mimic the others' advice here. Go to a meeting or two, find a mentor, start with a JABOD forge. But I'll add a few things.

For home foundries I like the Dave Gingery series of books - I started playing (and honestly, I'm still playing) with a variation on his furnaces found on the backyardmetalcasting site - can't post a link here, it's verbotten. They have a refractory recipe on there that uses a blend of portland cement, perlite, sand, and fireclay. It works okay-ish in a furnace, with the provision that it won't last forever, and this is important, can explode violently if you mess up the ramming. Ask me how I know. I've still got one of the ones I made that way, and still use occasionally, but it's not my first design choice these days. That mix makes a terrible, terrible forge liner too. Ask me how I know that one too. They spall out, usually not violently, it just breaks off at the edges of the fire until you end up with a huge hole.

Foundries are considerably more dangerous than most smithing - also a good area to find someone knowledgeable to guide you, although it's harder than finding a decent blacksmith. Casting is a blast, but molten metal can be prone to steam explosions and the big owies that make for scars with stories. When a crucible fails, 5 lbs of aluminum goes a very long ways indeed.

For the not heating the shop - it's partially a matter of directing the heat, and partly a matter of size. In a solid fuel forge, most of the heat will be going wherever the smoke goes. As that should be out of the shop, it's generally a good thing. And if we're being really honest, burning gas ain't great for you either. But consider say, a car - they put off tremendous amounts of heat around the engine and exhaust, but they would still take incredibly long times to heat up a closed garage. Or if you've ever had the heat go out and tried to run the stove and oven, it does a lousy job. Very small heat source, very localized. Forges work by creating in a very small area and using the least amount of fuel needed - otherwise they would be very inefficient and expensive to use.

It would be awesome to find a mentor or go to the meetings, I will definitely look into that.

Frosty,

Maybe I referred to the "liner" as the wrong thing. I haven't gotten a chance to read the Jargon section of the forum yet. Yes, I was talking about a solid fuel pan forge and asking about the sand and clay mix rammed in just as you described. Whatever I'm supposed to call it, thanks for the explanation of how it works. How often does that need to be re done?

The only clarification I needed to answer your question specifically was to know what kind of forge you wanted to line. Yes, a sand clay mixture in a pan forge is a liner. The old timey term was / is Clayed. 

Your only "mistake" was asking too vague a question, no biggy we all did that breaking into the craft. At least you have people you can ask.

How often to replace it?  When it needs replacing or just add more and hammer it in. 

If you use garden or road ditch material be VERY CAREFUL to clean all the rocks larger than coarse sand out. Stones will absorb water and if they get hotter than 212 degrees f. the water boils and can cause a steam explosion. This is B A D, picture sharp shards of broken rock flying out of the forge at a couple few hundred miles an hour.

There have been some horrible accidents around bonfires when boulders exploded. One extreme example is stuck in my minds eye when about 40' of a granite cliff face, known as Bonfire Cliff (rock?) blew out a piece of granite during a college spring break party. Killed IIRC 3 put a dozen in the hospital. Some got hit by rock shards and everybody got burned by the flying coals, pallets, etc. in the bonfire.

Just rocks around a campfire can get you though I don't know of fatalities, cuts, bruises and burns? Oh yeah, lots of those not to mention brush fires started by flying coals. The secret is to gradually warm the rocks up starting a foot or so from the fire and gradually move them closer when they warm up. Once a drop of water or spit sizzles on them let them sit there for a little while so the heat can soak to the center and dry out. Then you can move them close enough to rest a pan on, prop up hot dog skewers, etc. Remember, the larger the rock the longer it takes to dry out.

The First precaution is to NEVER take rocks out of a stream, pond or wet ground for your fire. If that's your only choice then drying them out gradually is a MUST. Building a fire ON a pile of rocks is playing Russian roulette with a Darwin Award as the prize and will get you sooner than later.

I know that's more info than you asked but you're going to be building fires that can melt steel so this is important to know. 

No, there's no "jargon" section here, it's an international forum with folks from all over the planet reading if not posting and terminology varies wildly. I try to get folks in the U.S. to use a sort of standard jargon but I'm up against thousands of guys just making terms up to describe that is happening, where ever they are.

Don't worry though, we're not going to send an enforcer to your place to break your knees for using the wrong term. All a jargon is is a common craft language using specific terms for specific things so everybody doesn't have to define or explain what they mean. Like all living languages it changes so we only really try to weed out modern slang terms. Nothing I do is EVER Rizz! 

So, relax. Just because someone points out a mistake does NOT mean we think you're stupid, etc. just mistaken. 

Sorry for the long ramble, one of my issues is getting pedantic. It can be an irritating habit know and I'm working on it. Unfortunately I've been polishing pedantry for more than 70 years now. Oh well. <sigh>

Frosty The Lucky.

 

Hi everyone,

 

I noticed our product Mortaclay-40d was mentioned here and wanted to clarify its intended use from a technical standpoint.

 

Mortaclay-40d is a high-temperature refractory mortar, designed specifically for bonding refractory bricks or cast segments. It is not formulated as a castable refractory and should not be poured or used as a structural lining material.

 

Regarding perlite: expanded perlite typically has a service temperature around 1470–1560 °F (800–850 °C) and is not suitable for forge interiors, welding heat, or melting operations. In forge environments it can soften, melt, or mechanically degrade.

 

For forge bodies, arches, or cast components, a proper refractory castable or refractory concrete is required, often combined with ceramic fiber insulation and expansion joints to handle thermal stress.

 

I'd like to make a disclaimer: I am not here to sell anything - only to help prevent material misuse and potential safety issues.

 

Happy forging, and thanks for the great technical discussion here!

Thanks for both the info and the disclaimer. For all the time we have to spend dealing with spammers and scammers, it's refreshing to get noncommercial input from a manufacturer.

My pleasure!

I am always enthusiastic about proper use of proper tools & materials by professionals.

The real question then is, do you have an analogue castable forge liner to Kastolite (high alumina for flux resistance, but still light enough to provide more insulation value than hard refractories like Greencast 97).

23 minutes ago, Latticino said:

The real question then is, do you have an analogue castable forge liner to Kastolite 90 (high alumina for flux resistance, but still light enough to provide more insulation value than hard refractories like Greencast 97).

Check DM, please - I've sent a question on technical characteristics you request, & I promised to remain as noncommercial publicly as possible.

On 11/3/2025 at 6:57 PM, BensonForge said:

What would you do?

Hello again!

Before recommending a specific material or castable type, it would really help to clarify a few technical points about the intended use case:

 

1. Will the refractory be in direct contact with molten metal, or only exposed to flame, hot gases, and radiant heat?

2. Which ecactly metals or alloys (or their vapors/fluxes) will the refractory lining be exposed to?

   For example: carbon steel grades, stainless steel grades, copper alloys, aluminum, fluxes, etc.

3. What is the maximum operating temperature you expect at the hot face?

4. How frequent are the thermal cycles?

   In other words, how often will the lining be heated to bright red heat and then dark cooled:

   • from about 1200 °C (≈2190 °F)

   • down to below 700 °C (≈1290 °F)

     Is this happening daily, weekly, or only occasionally?

   This is important because thermal shock resistance can be more critical than peak temperature alone.

 

With this information, we can provide proper technical recommendations based on refractory manufacturer data, rather than guessing or overspecifying the lining.

Happy to help clarify once the operating conditions are defined.

On 1/16/2026 at 4:07 PM, Latticino said:

The real question then is, do you have an analogue castable forge liner to Kastolite (high alumina for flux resistance, but still light enough to provide more insulation value than hard refractories like Greencast 97).

Greetings!

We've got a manufacturing plant producing castable refractories in the same general classes (including high-alumina HWI analogues), but for a meaningful recommendation it’s usually better to work from actual service conditions, not just a brand-to-brand analogue.

 

If you don’t mind sharing, a few points would help clarify what really matters in your case:

 

• What will the refractory be exposed to?

  Direct contact with molten metal, slag/flux, or primarily flame and hot gases?

• Which metals or alloys (and fluxes, if any) are involved, and roughly how long is the contact time?

• Operating temperature range at the hot face, and expected peak temperature.

• Thermal cycling frequency - how often the lining is heated to forging temperatures and cooled back down.

• Type of unit: forge, furnace, melter, size/capacity, and which zones you’re planning to cast (hot face, floor, burner area, etc.).

 

There are workable materials in the 90-93%+ Al₂O₃ range, but calcium content (medium-cement, low-cement, ultra-low cement, or no-cement systems) often matters as much as alumina percentage - especially for flux resistance and thermal shock behavior.

 

In some cases, a slightly lower Al₂O₃ but better-insulating or more flux-tolerant castable performs better than a dense high-alumina liner, depending on whether it’s a slag zone, melt zone, or just the hot face.

 

If you can outline the application, we’ll be happy to give a proper technical recommendation, not just point to a nameplate equivalent.

On 1/16/2026 at 4:07 PM, Latticino said:

The real question then is, do you have an analogue castable forge liner to Kastolite (high alumina for flux resistance, but still light enough to provide more insulation value than hard refractories like Greencast 97).

Greetings!

We've got a manufacturing plant producing castable refractories in the same general classes (including high-alumina HWI analogues), but for a meaningful recommendation it’s usually better to work from actual service conditions, not just a brand-to-brand analogue.

 

If you don’t mind sharing, a few points would help clarify what really matters in your case:

 

• What will the refractory be exposed to?

  Direct contact with molten metal, slag/flux, or primarily flame and hot gases?

• Which metals or alloys (and fluxes, if any) are involved, and roughly how long is the contact time?

• Operating temperature range at the hot face, and expected peak temperature.

• Thermal cycling frequency - how often the lining is heated to forging temperatures and cooled back down.

• Type of unit: forge, furnace, melter, size/capacity, and which zones you’re planning to cast (hot face, floor, burner area, etc.).

 

There are workable materials in the 90-93%+ Al₂O₃ range, but calcium content (medium-cement, low-cement, ultra-low cement, or no-cement systems) often matters as much as alumina percentage - especially for flux resistance and thermal shock behavior.

 

In some cases, a slightly lower Al₂O₃ but better-insulating or more flux-tolerant castable performs better than a dense high-alumina liner, depending on whether it’s a slag zone, melt zone, or just the hot face.

 

If you can outline the application, we’ll be happy to give a proper technical recommendation, not just point to a nameplate equivalent.



Additionally one important clarification that’s often overlooked:

 

Even high Al₂O₃ insulating castables (including those using alumina or corundum bubble aggregates) are not designed for long-term resistance to molten metal or slag. Their strength is thermal insulation - low thermal conductivity and good heat retention - not chemical or erosive resistance.

 

Such materials are typically intended as a backup / secondary lining, not as a working hot-face layer.

 

If thermal efficiency and durability are required, a two-layer lining approach is often the correct solution:

 

1. Hot-face / working layer

   A dense, heavy refractory castable or firebrick designed for direct contact with molten metal, slag, or aggressive vapors.

2. Backup / insulating layer

   Lightweight insulating brick or insulating castable placed behind the hot face to reduce heat loss and stabilize the structure.

 

This approach allows each material to do what it’s best at: chemical and mechanical resistance on the hot face, and thermal efficiency behind it.

 

---

 

On 1/19/2026 at 2:03 PM, Refractorist said:

Hello again!

Before recommending a specific material or castable type, it would really help to clarify a few technical points about the intended use case:

Thanks for the great information and detailed response. Seems like there's a lot I have to learn still since I don't exactly know the answers to those questions.