Forge build

[Mbmul175]

Hi guys, I'm looking to start my own blacksmith shop, I already have my anvil, now I only need a forge... 

I want to build a forced air gas forge, I have access to an entire steel workshop, so building it is not the problem. I need the math for a 4 burner forge with a burner configuration of "01010100010"(0= an open space,1 = blower) 

I like this configuratuon cause then I can have very high temp on a small spot or just regular high temp throughout... 

1: will this configuration work in the way I think it will ?

2: how do I make the blowers? (I can make everything on a lathe and milling machine if nessecary)

3: what should the "math" be for the forge?

4: what will the gas consumption be per blower, per hour?

5: what can I use as refractory material, where can I accuire it ?

6: how do I assemble the whole mish-mash of parts !?

Thanks for reading, I appreciate any help you can offer.

 

 

 

[ThomasPowers]

Way too little information to answer most of these questions; if I were to ask you "how many miles per gallon will my vehicle use"  without telling you things like size of vehicle, load, how it's being driven, etc; could you give me a good answer?

Things like where to buy refractory material are sort of LOCATION dependent which you didn't supply.

Gas consumption is from 0 to infinity depending on information you didn't supply

etc

BTW do you mean "burners" on #2; you buy blowers---even if you have a machineshop...

[WayneCoeArtistBlacksmith]

check out the attachments on the Forge Supplies page at www.WayneCoeArtistBlacksmith.com.  There is the Build a Gas Forge for instructions on how I like to build a gas forge.  If you want to build a forced air forge check out the Ribbon Burner attachment.

Let me know if I can help you.

 

[Mikey98118]

 

You seam to be confusing fan-blown and naturally aspirated burners. A four blower forge? I don't think so! Such a beast would need so much exhaust area it could only be half enclosed. You need to consider a large ribbon burner; that is the only type of blown burner that is going to work for your desires.  Go to the Wayne Coe site, and start reading about them.

 

[Mbmul175]

Sorry for the insufficient info...

The whole story ...

I live in south africa, where there are not many blacksmiths as far as I'm aware. So all my info comes from scraps I found on google.

I struggle to find anything specific on how to build burners*( not blowers, sorry for that) ,measurements , the adequate size relevant to the forge, the consumption of such a forge...

So ribbon burners will work right ? I have considered them, but read that they are hard to work with , is that true ?

If you guys know where I can get any blueprints or measurements that would be great, cause I'm in the dark here 

Thanks for your help so far

Michael.

 

[Glenn]

Look at the forum section South African Highveld on this site. Some good folks in YOUR area. They should be able to help you. Take what Wayne and Mikey says and run with it. They know their stuff. Frosty has plans for burners on this site.

[Mikey98118]

You should also consider going with Frosty "T" burners in a brick pile forge; there is no other kind of forge that can be reconfigured while a guy tries to figure out just what the heck will best suite his needs.

[Mbmul175]

I already haflve the plans for the T burner and an idea for an ajustable brick forge, so now the vacation must come so that j can build it . how do I know if I have the correct flame ? 

Thanks

Michael.

 

[Frosty]

You tune a burner after you build it, we can walk you through then. Doing it now is only going to confuse you. Be patient, taking your time and doing one thing at a time will get you there much faster and in better condition.

Another piece of advice, once you pick a set of plans stick to it, don't jump around. Trying to mix and match designs and plans before you know whats happening and why will only screw you up. Honest, it happens all the time and we end up trying to untangle guy's brains for them. We're blacksmiths and tend to use progressively larger hammers to untangle things.

Frosty The Lucky.

[Mbmul175]

Thanks frosty, I'm using your T burner design with a 1"-3/4" T. I want to use 2 if them in a small forge which is 3 bricks flat, on them are 1.5 bricks on their sides at each side. And then 3 on top again. The opening will roughly be the size of a standard brick... Will that suffice ? Too many burners ?

Thanks for the help, 

Michael.

[Mikey98118]

"T" burners and brick pile forges are Frost's territory; not mine, but I will point out that you want to arrange the burners so that its end stops about 1" inside the brick you set it in. This will turn that portion of brick to super-heat into incandecent temperatures; turning it into a large ignition surface, which I believe is necessarry to get all any burner design has in it.

If you don't believe the brick can stand up to this treatment (ex. soft  insulting fire bricks), than use a small amount of 3000 degree castable from, someone like Wayne to make up a little square brick with a builtin hole for the burner(s), and buggy on.

[Mbmul175]

17 hours ago, Mikey98118 said:

"T" burners and brick pile forges are Frost's territory

Frosty, 

Thanks for posting your T burner plans online.

Do you perhaps have plans for a Brick pile forge online ?

I was just curious about roughly how much propane one of the 1"-3/4" T burners will use hourly ?

Thanks 

Michael.

[Buzzkill]

MbMul175,

No one is going to be able to accurately answer that question.  I can tell you what my T burner uses in my forge at my location at the temperatures at which I forge and with the openings I have in my forge.  The point is there are a lot of variables which will affect how much fuel you use in a given amount of time. 

How well your burner is tuned, your elevation and general weather conditions, the insulation of your forge, the size of the openings, and the temperature you are trying to reach (and a few other factors) will all potentially affect your fuel usage and are not likely to be identical to anyone else's situation.

For rough figuring I get close to 10 hours of time from one 20 pound propane tank when I'm just doing "regular" forging.  If I were trying to forge weld it might be half that.  I don't know because I haven't tried it with my forge yet. My forge is fairly small though - roughly 216 cubic inches of volume.

[Mikey98118]

The other part of his question is on finding a plan for a brick pile forge. On the one hand it appears to be a conundrum, since the whole point of such a forge is to be configurable, and therefore formless in a practical sense.

Not only are "the Devil in the details," but such structures are literally  nothing but details.

[Frosty]

Michael: You and everybody who uses the plans I published are more than welcome to them. I should've posted good drawings years ago and a how to.

Anyway, there really is no "plans" for a brick pile forge, like Mike says the idea is to have a chamber you can alter as needed. The basic brick pile forge (BPF) I use at Demos is this.

I lay down a brick floor 18" x 27" on a steel cart. The deck needs to be larger than the forge's overall dimensions. Most of the extra length extends in front of the working opening.

The volume I aim for is roughly 350 cu/in The interior dimensions are 9" x 9" x 4.5" That's 9" deep x 9" wide x 4.5" high. Those dimensions add up to 364 cu/in but it's easy to squeeze the sides in and make it as small as necessary. This is a VERY general single burner set up.

I lay the bricks fat for stability so the sides are 2 bricks high. One stack on each side. I use two stacks end to end across the back. This allows you to slide them apart for a pass through opening to work the center of a long bar and being as the two stacks are so much longer than the forge chamber is wide you can position the pass through anywhere across the forge chamber.

I use a single brick on edge for the front door it to can be positioned anywhere. I bring about 2x as many bricks as necessary to build  the basic forge I may need larger or to change it and it's not rare to drop and break a brick.

What about the top you ask? The lid is bricks laying flat end to end from the sides. They over lap the back. It takes 3 sets to cover the entire chamber and over hangs the front opening up to half their width, say 2" or so. Half the lid bricks lay flat on the sides and I lay a couple more bricks over the supported sides for stability.

I make burner ports by sliding a pair apart just enough to admit the end of the burner a little way, say 1/2" or less. Most of my burners rest on top of my shop forge so I leave a gap in the top bricks. I've also aimed a burner through a gap where the lid and sidewall meets for a horizontal flame. This one works nicely. You can aim it in the front opening if you'd like. Experiment. Being able to experiment with size, shape and burner alignment is largely what a brick pile forge is about.

I know this sounds involved but it's literally a building blocks game. The above forge is a 1 burner forge. Being all heavy fire brick it never gets to a good welding heat, after 3 hrs it's about topped out in the high yellow. It works just as well with the side bricks on edge with an insulating brick inside and a hard brick outside and use insulating bricks for the end walls and lid.

I just got tired of light bricks breaking they do NOT like rapid temperature changes, a pottery kiln takes hours to come to temperature but a forge does it in minutes they cool off quickly too, half an hour for soft brick. This eats soft brick.

Oh and for a more permanent brick pile forge make the deck from soft insulating fire brick but overlay the fire contact with split hard brick.

The rule of thumb for how many burners to use is 1 ea. well tuned 3/4" burner for 300-350 cu/in. will bring an insulated chamber to welding temp. This is calculated using the cross section area of the burner tube as the base. If you increase it to 1" dia, the area is doubled as is the output. Make one 1/2" dia and it is halves as is the output. Follow the same rule of thumb for jet dia. as well.

Once you have the basic sizes you need just adjust till it does what you want.

Frosty The Lucky.

[Mbmul175]

Thanks frosty ,

If I find a layout I like , can I use fire cement to seal little openings between bricks and maybe for a lining as well ? 

What can I do to make a BPF reach welding temp ? In stead if using those soft bricks...

Thanks,

Michael.

 

[Frosty]

Sealing the brick is not only not necessary it's not a good thing. You aren't building a furnace, there's no reason to cement anything.

Once you find a forge shape you like build it from better materials unless you like running 2x the burners and fuel. Or you can shrink the size of the chamber till it gets hot enough. This is a brute strength technique, valid but expensive in fuel.

A fire brick has a R value of 1 per it's thickness. To have the same R value as is used in a house wall, it'd have to be 1' thick. R value is the insulating properties of 1 FOOT of limestone. Fire brick is a SLIGHTLY better insulator than limestone and it's a heck of a heat sink.

By time you get the inside of your forge to yellow heat the outside will be turning red.

Frosty The Lucky.

[Mbmul175]

15 hours ago, Frosty said:

Sealing the brick is not only not necessary it's not a good thing.

Frosty The Lucky.

Why is it not a good thing ? 

For instance I do seal it, what will happen ?

[Frosty]

Refractory cement isn't for "sealing" masonry it's for sticking (Cementing) it together. Thermal cycling as your forge heats and cools WILL cause it to expand and contract. Cementing it into ONE piece means those forces will concentrate at blemishes be they nicks, mortar joints or corners. If the cement is good enough it will cause the bricks to break with the thermal cycling. If the mortar isn't that strong then the mortar will break up and as the bricks shift the pieces will force the bricks farther apart and do exactly the opposite of what you want.

Lastly cementing the brick undos one of the prime benefits of a brick pile forge, it commits you to ONE shape. Brick pile forges real strength is their versatility especially for someone learning the craft. You can change the shape and size at will, I have a pair of tongs I can use on brick so I can adjust WHILE it's running. Brick will degrade with the thermal cycling as well and if they're cemented you have to break them out and take the chance of breaking good bricks in the process.

That's my reasoning for NOT cementing a brick pile forge.

Frosty The Lucky.

 

[Mikey98118]

Of course, bricks themselves have corners, which cause some minor problems, because they are external; Internal corners are a MAJOR problem, as they are natural born crack starters. "We don't need no stinking cracks!"

[Mbmul175]

Thanks frosty, 

I see what you meant, but is there any way that I can get my forge up to welding temp ?

Michael. 

[Frosty]

Reduce the internal volume by more than half or double the burners and burn lots of fuel. Or build a more conventional forge with an insulated liner kiln washed for increased durability. Soft fire brick will last you 2-4 firings depending on how fast you bring it up to temperature and how long you let it cool, the slower the better. It will however reach welding temps on the scale.

Build a forge with 2 ea. 25mm layers of ceramic refractory wool outer liner for insulation and kiln wash it with a high alumina 3,000f refractory kiln wash up to about 12mm or so thick. A cylindrical chamber with a high alumina kiln shelf floor is a good shape. it has a flat floor so stuff stays put and kiln shelf is easy to replace when it's worn out.

Aim for around 300-350 cu/in volume and one well tuned 3/4" T burner should do it for you.

Thanks for catching that Mike you're absolutely right, external cracks don't propagate through the body like internal ones do they just round the corners off till you have a potato shaped brick with a skin condition.

Frosty The Lucky.

[Mbmul175]

Thanks for all the advice frosty, I'll be sure to put it to good use.

Michael.

 

[Mbmul175]

My first burner is done !!!

Its Untested tho

Frosty, I couldnt find the exact fittings your plans specified, but the inside is about the same as the ppab calls for . 

[Frosty]

Who's plans did you follow? Certainly not mine. That's sort of a jumble don't you think? Performance is going to suffer on account of several  mistakes. A bushing reducer to convert a 1" T to 3/4" will induce turbulence that will reduce induction. Then splicing 2 short nipples together is another feature that will make the turbulence worse. Lastly a bell reducer is too abrupt a transition to make a good flare or output nozzle.

The fitting you used to mount the jet and connect the hose is fine so long as the jet is aimed straight down the center of the tube. Your burner has other problems I don't know how you're going to tune out of it. Unless you clean it up.

Frosty The Lucky.