Lining a brake drum forge

[The White Horse LHS]

Dear friends

My name is Seán Shields andI am a battle re-enactor and I am new to the world of heat forging. My intention is to make simple equipment for my group. I have built a pretty reasonable break drum forge set in a square metal base with stand, canopy and bellows, and it works great but my problem is lining the inside of the drum as to create a bowl in the centre. As the drum is a large one it will use too much fuel and I wish to raise the internal height of the drum. I know people out there frown on these types of forges, but it was cheap to build and when I develop my skills and confidence I will spend the money to construct a forge that will best suit my needs. I would greatly appreciate any advice people could give me, I have tried clay and concrete but these materials just don't stand up to heat.

Many thanks. Seán

[Frosty]

Welcome aboard Sean, glad to have you. If you'll put your general location in the header you might be surprised how many of the IFI gang live within visiting distance.

How are you applying the clay? People have been forging in clay fire pots, bowls for a couple thousand years but there are a couple tricks to making clay work. No, concrete won't work for a fire contact surface, even in BBQs and fireplaces it's been mixed with other stuff to withstand the moderate temps of a wood or charcoal cooking fire. A drafted fire is a whole different kettle of worms.

There are "better" fire pots than a brake drum but there are worse ones too. How well any pot works is in the hands of the smith not the tool. My usual response at demos to someone who doesn't like how I'm doing something is to offer them the hammer. I've never gotten a taker. Go figure.

What period are you reenacting? What are you forging, it can make a difference in how you make the forge.

Frosty The Lucky.

[Charles R. Stevens]

Cement is clay and lime subjected to high heat and grount to drive if the molecular water, heating it in a fire pot will convert it back to powder, clay needs grog, comercialy coffie cups and such are made with ground fired (vitrified) clay and unfired clay in a 1/10-1/3 clay  and the rest grog. In your aplication a 1/3 clay and and 2/3 sand will work. The clay soil that i find at the botom of any hole I dig here in south central Oklahoma just has to be rammed into shape. Your clay may verry, if you are sorcing clay from a potter or such let them know, because you want relitivly dry material. To wet and it cracks as it dries, same with not enugh grog. If you mix from scratch sorce some waterglass (sodium silicat) and use that to wet the clay and grog. Place it in a coverd container to "temper". Some old recipies caled for clay, ash and  sand, hardwood ash and coal ash are high in silicates. 

To rais your fire, use a bullet grate (a 2" pipe cap with a 3/4" hole drilled in the center) and to get more lift use a pipe nipple underneath it cut to length. In practice ash will collect in the drum and form a slope, if you dont get wild clearing it out it will form a slope and make the bowl smaller, and with a bullet grate the slag will flow down around the cap and cool, forming a "donut" that you can fish out. 

For the record, the reason I dont care for brake drum or break rotor firepots, is its more work and expense to use one than to make a side blast (more historicly acerat anyway) by the time you cut a plate for the bottom, sorce 2" black pipe fitings, drill holes and bolt it to gether, i can slap together a wooden box, poke a peice of 3/4" black pipe, fill it with dirt, dig out a fire bowl and be forging for a day and a half. 

If you use an electric triler breke drum or one of an old car (model T) that is cast or rivited to the bering hub then all you need is legs, and plumbing parts. Thats how they started out back in the day.

for the work and expense have a pot welded up along with a tweer (2"square tubing or exast tubing works just fine) if you want a bottom blast. Infact take a welding class at your local votec or comunity colage and build one yourself if you insist on a fire pot. Or take a oil drain pan, have your local exaust shop build you a 2" "T" for a tweer and clay your new "forge) looks a heck of a lot like a rivit forge to me...

I

[The White Horse LHS]

Greetings Gentlemen.

Thank you for your response. At the moment I am forging spearheads, axe heads, nails, hinges, knives and war hammers for my group. My forge is working very well except for the lining failing and cracking in the heat. My group the White Horse Living History Society is based in Ireland and we portray the Bronze and Iron age, the Viking, Norman and Roman periods. I also belong to an American civil war group. I am an Art teacher and Artist and I love to work with my hands, when I was in secondary school blacksmithing was a major part of my metalwork module and I always loved it, so last year I set out to build a forge and just have fun. I will be picking every ones brain as I am sure there will be a lot of trail and error

            Kindest regards. Seán

[LastRonin]

One more note... PICTURES, we all love pictures. And not necessarily only of forged works, anything cool, neat and interesting that may be relatable to any of the topics this vast forum touches on.

Edited May 10, 2015 by LastRonin
spelling

[Charles R. Stevens]

Your welcome, lol. The only "Irish" forge I have heard of was a slab of granit with a bowl chiped into it and a chanel carved out to lay in a tweer. ive seen simular setups cast in concreat (not the best) and set up with a ducks nest grate. You wont be alone, many smiths herer are reenactors. 

As to your claying issue, daub or cob should work (we call it adobe here) the trick is not to get it to wet, just barly damp, if it comes out if the ground its all good. You want to have to "pound" it in with a mallet or short peice of lumber.

Edited May 10, 2015 by Charles R. Stevens

[Frosty]

Sean: The periods you're talking about didn't use bottom blast forges, at least I don't believe they did. Side blast is much easier to make and maintain and lower tech level. If you ram one up out of field clay don't make mud out of it, just enough moisture to hammer it hard is perfect.

I like a ratio of 3pts. sand to 1or2 pts. clay and if you're making a permanent forge 1/2 pt. portland cement. Mix the dry ingredients then add water slowly while mixing till it forms a hard clump when squeezed in your fist. If it crumbles it's too dry, if it leaves streaks on your hand it's too wet. Adjust dry with sand and moisten a dribble at a time.

Then ram (whock) it in with a wooden mallet or 2x4, 4x4, ball bat, etc. end on till the whocker bounces. Then strike (scrape) it smooth. The smoother it is the less stuff will stick to it, you can even burnish it with coarse cloth like burlap if you want. Smoother is better.

This is the same mix and technique I recommend for claying a cast iron forge pan. It only takes a couple few inches of hard clay to  keep the table or pan from getting too hot. Too hot is causing a wood table/box to char or a cast forge pan to heat check.

Frosty The Lucky.

[Charles R. Stevens]

Rare is theday that I disagree with Master Frost, but I recomend against cement, as it is clay and lime, heated to drive if the molecular water and grount. Heating it in a forge reverses the process. Atleast leave it out of the 1/2" or so in the fire bowl, that will vitrify overtime anyway. If mixing from scratch (dry clay powder and grog or sand) weting it with waterglass (sodium silicat?) will make for a more durable product. As will hard wood or coal ash. Some folks buy stove cement (alumina based not portland based cement) in quart tubs and delute it with water and mix in perlite or vermiculite to make a light insulating refractory, coating the mix with and 1/8-1/4 of plane refractory cement for durability. All liners are prone to crack, like cement. Intall it as dry as you can reasnably work it and score to control where it cracks. 

A wooden box set on legs with a ground forge built in it is probbably the most aproriate to your time period, as we modern men dong care to forge on our knees. A smallish block of steel is aproriat for your time period as well. (That set up covers a lot of time) two single bellows can be rigged to operate of of one pole, not strictly acurat for iron age reinacting but certainly for early middle ages. Bellows thralls being hard to come by in this day and age. Marcowits has a nice blog on "forging out the bits" covering viking era smithing. As well as Tomas Powers extisive knowlege and reference library. They are far from the only resorces offcorse. 

[LastRonin]

I don't think The White Horse LHS was asking about period correct forges, just info on how to line his existing brake drum forge to create more of a bowl shape.

[Charles R. Stevens]

Tru Last Ronin, but a ground forge in a box is easer that lining a largish brake drum, because of the relitively small size and all, it ends up being a donut that once cracked is easy to remove,

[Frosty]

"MASTER Frost?" Charles is picking on me again!!

Portland cement is burnt Lime AKA quick lime "not clay though that's the common belief" and ash that's mixed in a ball mill. Romans invented hydraulic cement when they discovered adding volcanic ash to lime mortar made cement and adding gravel to cement made concrete. Modern concrete plants make their own ash but I don't know what they use for raw material.

I agree, using concrete in fire contact is generally a B-A-D idea as the water boils out when it reaches just above boiling temp. A fire place mix will handle fire places, BQQs, etc. but still doesn't do well in HOT fires.

A 1/2pt out of 5-6 pts is low enough it can't form a concrete, it just sticks particles together in the beginning. If it gets hot enough to return the lime to quick lime it will rehydrate from the surrounding mix very quickly.

Yeah I spent time working in the concrete lab when I worked at the state materials lab but not being a chemist they made me do other stuff in short order. Anyway, even though that low a percentage won't spall or degrade in a clay liner for a forge pan it's pretty much completely unnecessary. The clay is plenty to maintain shape and be sturdy enough to last well.

Frosty The Lucky.

 

[Charles R. Stevens]

I stand corected, limestone and clay, sand, shale, ifon ore bouxsite, fly ash and /or clinker... Lol

 

[The White Horse LHS]

I don't think The White Horse LHS was asking about period correct forges, just info on how to line his existing brake drum forge to create more of a bowl shape.

​LastRonin is correct gentlemen. I apologise if I didn't make my self a lot clearer in my explanation. Please check out the '' White Horse Living History Society'' facebook page, you will learn more about what we do by looking through our photos. You will also find photos under my name ''Seán Shields'' on the same page, they show a lot of the stuff I make. All my pics are on an external hard drive as I had my laptop repaired recently, so I will post pics as soon as I can. 

I am going to read through all the info guys but some of the stuff you mention is not available here in Ireland. I need to devise a lining system that doesn't crack and where everything doesn't stick to it. I was thinking about firebrick and cutting it to the shape of the drum, any ideas on this guys? please share.

Thanks for you advice so far guys. Kindest regards. Seán

[Charles R. Stevens]

Coal slag sticks to fire brick. Almost any refractory will crack, like co creat it's about limiting and controlling the cracking. Good bet their is clay and sand in Iraland, if not from the back garden, a potter then cat liter

[Frosty]

I only mentioned period forges because I thought of them and who knows what might be useful info. You don't think I read up on concrete and portland cement for fun do you? You know Charles when I think about I don't know how they make their ash but it has to mimic volcanic ash which is basically vitrified glassy bubbles. Like clinker. They roast the lime in a large rotating drum with a big torch like flame firing down the center. They blow the crushed limestone into it and it burns almost instantly making quick lime. If they fired crushed clay into the torch in the same manner it'd fire like pottery one particle at a time almost instantly. Ash. The balls in the mill would blend it like a muller does casting sand.

I wonder if I know any of the guys in the State lab anymore or I might just call one of the concrete plants. The plant manager of the one close has Akbash guardian dogs and we had Great Pyrenees Mountain dogs. We have good talks, very cool dogs.

Now my curiosity is all wound up if I only don't forget. I'll write a note.

Frosty The Lucky.

 

[Charles R. Stevens]

I am glad I'm not the only one that gets somthing stuck in my head, I either have to learn about it, do it or build it (some times just planning it and puting it in my note book (somthing like volume 25) works)

[LastRonin]

Sorry Frosty and Charles. I didn't mean to be rude, shoot, I enjoyed reading the info on period forges. I just thought it seemed his original question may have been getting lost amid the other information.

Humbly, 

Ken

[Frosty]

No you're not alone on that one Charles. It's a little weird how much some of us have in common isn't it? Then again it makes us feel at home. I have many notebooks and stacks of graph paper tablets of sketches and drawings.

You were rude Ken!? And I missed it. DRATS!

Don't sweat kicking me off a side track, I tend to hijack threads being silly and really don't mind folk telling me so. Just don't try being too polite. We TBI survivors do better if you're direct with us, no need to be mean but just tell us if we're getting off track. Hinting around, trying to be kind just distracts us from your point. We'll get lost trying to follow everything you say and lose or miss the point. It's a TBI / Stroke issue.

It ISN'T rude, it's the best way to get us on track.

Frosty The Lucky.

[The White Horse LHS]

Hi Guys.

 I can get access to potters/modelling clay with about 40%grog. Would that do? and what is the best way to set it in the drum?

 

                                                                                    Regards     Seán 

[Charles R. Stevens]

I can't blame TBI, but ADD isn't much better. 

I would add either 1/2 or 100% sand or grog. About 1/3 clay works real well usualy, the clay as deliverd will tend to crack in amounts over about 1/4", but if you cut it farther, you can put a thin layer of the as deliverd mix, or just put a flower pot in it and fill in around it with sand or cat litter, sure the pot wont last fore erver but if your just a little care full  it will last a good wile and is cheep. Ive made forges in big flowerpots, but just as a body, used dirt to fill in to make the fire bowl. 

[Frosty]

That's pretty high fallutin clay for us blacksmith types but it should work. Like Charles says though you want to add plenty of sand to it or it'll shrink check as it dries. Ideally it should be just damp enough to make a clump in your hand if squeezed hard and break cleanly without leaving muddy streaks. If it crumbles it's too dry if it leaves streaks it's too wet.

I like Steve's sometimes sign off, "I'm OCD and ADD everything has to be perfect but not for long."

Frosty The Lucky.

[Stephen Jones]

What about the screed they use to make fireplaces? That should be good to 1200C temp wise id guess

 

[Charles R. Stevens]

Alumina based cement works well (but clinker sticks to it), as dose "fire clay" sold by masonry stores as its clay one wants to mix it about one part clay to 2 parts sand, but as a powder, add a bit of water and put it in a five gallon plastic pail and cover and let it "case" ad a sprinkle of water every day or two if its to dry. Always easer to add a bit of water than to take it out, but in the case of clay and sand you can just leave off the lid to dry it a bit (cover and case to get red of any crust). 

I know this all sounds compicated but really we are just playing with mud paties, and humans have been building houses with mud for malinia. Longer than we have been playing with iron (but we even build the blumidaries and smelters from clay and sand)

Edited May 12, 2015 by Charles R. Stevens

[Frosty]

What about the screed they use to make fireplaces? That should be good to 1200C temp wise id guess

 

​I'm not familiar with the term "screed" as you use it but if it's good to 1,200C it's more than refractory enough for lining a solid fuel forge.

Frosty The Lucky.

[Stephen Jones]

http://www.ebay.com/itm/Castable-Refractory-Cement-clay-fire-place-brick-mortar-stove-chiminea-repair-/180869710817?pt=LH_DefaultDomain_0&hash=item2a1cacc3e1

 

this stuff is screed