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I Forge Iron

1m X 1m Side Blast


mechelement

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I finally got my wife a forge. It’s a 1m square Greystone Forge sideblast. We are running coke in it. I really had no clue what to expect. We are much more familiar with a gas forge, but my wife has wanted one of these coke forges as long as I’ve known her. These solid fuel forges heat steel FAST.

Getting this thing and then modifying it to make it work with our setup was quite a task. First I tried to get the next size smaller, but the shipper absolutely destroyed it. Then the importer decided to stop importing these things, so he gave me a great deal on the 1m square one, the only one left. It arrived unscathed. I needed to have this thing mobile. I know that sounds crazy, but I am currently wheeling it in and out of our garage. It’s 6’-8” tall. I had to shave the legs down from the bottom 2” and re-weld the feet back. I installed stud mount ratcheting equipment moving leveling casters on the feet. It raised the forge 1” from where it originally was, so 6’-9” tall now! The equipment casters are awesome. It moves like butter.

For lining the pan, I put a couple of inches of sand and ash in as an insulator. The bottom definitely got hot when running it today. I think the blower is so powerful, it creates a divot in the sand when blasting the coke. We pulled out a clinker the size of a small dinner plate that was as brittle as glass and a glob of a clinker over it. The water in the tank gets a lot hotter than I thought it would as well. It boiled slightly.

What do you recommend lining the bottom of this forge with? Refractory cement or a combination of that and brick? How close to the conical tuyere should I get with the cement/bricks? Should I line the entire 1m square pan or just an area in front of the tuyere where the forging predominantly takes place?

I have a bunch of questions, but I’ll search a bit more prior to asking. 

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Sounds like you may have melted some sand into glass, which would be expected, to go along with your clinker. 

By "tank" I assume you mean the bosh.  The water certainly does get hot in the bosh as it transfers heat away from the tuyere.

If by "tank" you mean a metal bucket, move it further from the fire :P

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11 hours ago, MishlessFeat said:

Sounds like you may have melted some sand into glass, which would be expected, to go along with your clinker. 

By "tank" I assume you mean the bosh.  The water certainly does get hot in the bosh as it transfers heat away from the tuyere.

If by "tank" you mean a metal bucket, move it further from the fire :P

Yeah, the whole turning sand into glass thing really got me thinking this could actually melt through the pan unless I come up with something a bit more than just sand and ash. Perhaps Inswool coated with Bubble Alumina?

Yes, bosh in lieu of tank.

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It's getting hot enough to start sagging. There's only one small angle iron under the pan, centered. That angle looked like it was sagging when hot. I don't mind doing some structural reinforcing, but would like to reflect the heat upward if possible.

I have a small fortune invested into this piece of equipment... Perhaps I'm overreacting because of it. 

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TIt looks to me like you are building your fire too low in the forge, and so there’s not enough insulation between the bottom of the fire and the sheet metal pan. Increase the depth of sand/ash/kitty litter/dirt so that it’s only a little bit below the bottom edge of the tuyere. 

IFI member EverythingMac has a video showing him putting the fill in his own side-blast: 

https://youtu.be/6ExLtAOqBk8

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Forgot to mention. The picture with just sand in it, we actually took out around 100# of that sand and replaced it with a bunch of ash. It was quite a bit lower than what's pictured. We did that because of what Greystone Forge displays on their website. Basically it looks like he has only a couple of inches of sand in the box, then fills it with coke.

EverythingMac mentioned something turning into glass, then ash? Is that refractory sand or cement he spread around there? 

Does anyone run Inswool then coat it with a refractory cement or the like?

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16 hours ago, mechelement said:

Does anyone run Inswool then coat it with a refractory cement or the like?

Could you build a high-tech refractory firepot for a side-blast? Yeah, probably. Is it a good idea? Probably not. You're going to get problems with clinker sticking to the refractory, the cement getting chipped and cracked by having the fuel and clinker raked around it, and any exposed ceramic wool will end up shedding fibers into the air stream and possibly getting breathed by you the smith. You don't want any of that. Basically, you're spending a lot of money to replace something that you can get low cost or free with something that isn't going to perform as well. Why bother?

16 hours ago, mechelement said:

The picture with just sand in it, we actually took out around 100# of that sand and replaced it with a bunch of ash. It was quite a bit lower than what's pictured.

In other words, you put even less insulation between the fire and the bottom of the forge. Well, there's your problem! 

18 hours ago, mechelement said:

It looks like that guy used a bunch of fire brick and refractory cement?

No, it's just regular bricks and sand. As Andy notes in the video, the bricks are just to take up space, so that he doesn't have to buy too many bags of sand. Joshua De Lisle (in the second video Dale Russell posted) mentions that he's using ordinary builder's sand. My own forge also uses regular building sand, from my neighbor who over-ordered sand for a building project by more than two tons! (He was more than happy for me to take however much I wanted.)

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the other advantage of bricks in the bottom of the forge is that when clean out and remodel the fire bowl you don’t dig down to close to the floor. Typically the back wall and floor will be lined with brick. 

How high is the bottom of the hole in the tuyere of the bottom? Typical recommendations is for the bottom of the fire bowl to be no more than an inch lower. This gives a place for the slag to collect below the air blast. If you don’t have 2” of insulation (sand, ash, brick) as a minimum your going to have to figure out how to adjust the tuyere. 

Your wife has great taste in forges.

 

the other advantage of bricks in the bottom of the forge is that when clean out and remodel the fire bowl you don’t dig down to close to the floor. Typically the back wall and floor will be lined with brick. 

How high is the bottom of the hole in the tuyere of the bottom? Typical recommendations is for the bottom of the fire bowl to be no more than an inch lower. This gives a place for the slag to collect below the air blast. If you don’t have 2” of insulation (sand, ash, brick) as a minimum your going to have to figure out how to adjust the tuyere. 

Your wife has great taste in forges.

Ps, dry lay the bricks, they aren’t going anywhere with sand and ash on top of them.

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3.5” from bottom of tuyere to the steel pan. 

4.75” from the bottom of the hole in the tuyere to the steel pan. The hole is 1” in diameter. 

Not to sound like a complete donkey here, but there is a 0.00% chance of relocating the tuyere. There’s 1.5” between the underside of the pan and the blower motor housing. 

Here’s a pic of the sand moved away. (Please ignore the fail of a coal rake that burned up a bit.) It’s “tube sand” not “building sand.” By building sand, do you mean fill dirt?

I posted a pic of some caulking I used on this thing. I pulled out the junk white silicone that wasn’t doing anything and used that Mill-PAC Black instead. I’ve yet to refinish the outside part with the Rutland stuff. The white silicone that was painted black isn’t really doing anything there either. I figured properly applied high temp black silicone would be better. 

I’d like to make this lighter if at all possible. I have around 150# of sand and 150# of coke in there. If fire brick is the way to go, I’m game. Do I set it in a bed of sand as well as sand over the brick? Ditch the tube sand and go grab some fill dirt on one of my construction sites? Is the plate of glass normal? Do we just leave it in there and roll with it?

BC68F671-3E9E-45BA-BC89-1D20382A8302.jpeg

9CB1BDA6-F43F-404D-8C12-5571C51E3C4A.jpeg

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So you need 3 3/4-4” of brick or soil insulation in the bottom.  That leaves 3/4-1” of space for slag to collect under the tuyere. How much from the top of the hearth to the bottom of the opening in the tuyere? You may have to notch the sides if the hot spot isn’t high enugh so you can put long stock threw the center. My suggestion would be to fill the forge pan to with in an inch of the top of the hearth. Then use a progreso soup can and water to form a fire bowl. You will still have an inch of reserve fuel on the table, but you don’t need as much. Brick can certainly be used instead and I would be inclined to acual fill the heart with lose brick and forme a smaller box for the sand/ash (I prefer clay cat litter and ash myself) sand acualy sucks as fill because clinker is formed from sand in the coal. 

A 1” ID tuyere will feed a 6-8” fireball so a 8-12” brick box is good. A 4x8” trench will fuel conservative for most work opened up to 8x8” for bigger work. 

 

 

AA423003-C981-4F68-9A1C-5C5796403D4C.jpeg

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So sand should be touching / enveloping the tuyere?

Is firebrick relatively light compared to sand? I’m thinking it would be close to 800# of sand if I used it exclusively to fill the hearth. Clay cat litter sounds interesting... will it turn to glass like sand? I’m short on ash right now because I dumped it all into the current conglomeration I have going on there.

The hearth is approximately 10” +/- 1/4” deep. I’m measuring on the outside of the hearth because it’s full of sand and coke and there’s a lip on three sides.

Top of hole in tuyere to top of hearth edge is 5”.

Bottom of hole in tuyere to top of hearth edge is 6”. 

If I'm reading your charts correctly, it appears as though it conforms to the second column from the left. 

I really appreciate all of this info. I hope to be able to contribute in return one day.

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Yes, the tuyere should be covered in sand. 

Brick and sand weigh about the same. Cat litter/drysweep will clump a bit but no it will not become glassy slag and it is lighter than sand.

your spot on, fill the hearth to about one inch from the top and dig your fire bowl to within 1” of the bottom of hole in the tuyere. This gives a place for the slag to collect below the air supply. If you go to deep the slag will get under the tueyer and that can be a pita. If you use cat litter, be conservative with using water for fire management. Personaly I like to set two bricks right at the hight that will be the bottom of my fire bowl. That way when I rebuild the fire I don’t get to aggressive and dig down to deep. 

As the pan fills with ash you will have to remove some of your fill material. 

 

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What Charles said, with a small clarification:

1 minute ago, Charles R. Stevens said:

dig your fire bowl to within 1” of the bottom of hole in the tuyere

That should be "Dig your fire bowl down to one inch below the bottom of the hole in the tuyere."

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On 10/25/2018 at 10:59 AM, Charles R. Stevens said:

Yes, the tuyere should be covered in sand. 

Brick and sand weigh about the same. Cat litter/drysweep will clump a bit but no it will not become glassy slag and it is lighter than sand.

your spot on, fill the hearth to about one inch from the top and dig your fire bowl to within 1” of the bottom of hole in the tuyere. This gives a place for the slag to collect below the air supply. If you go to deep the slag will get under the tueyer and that can be a pita. If you use cat litter, be conservative with using water for fire management. Personaly I like to set two bricks right at the hight that will be the bottom of my fire bowl. That way when I rebuild the fire I don’t get to aggressive and dig down to deep. 

As the pan fills with ash you will have to remove some of your fill material. 

 

Pardon my ignorance, but I’m not following you with the water use. What catches on fire beyond the coke getting hot 

On 10/25/2018 at 11:03 AM, JHCC said:

What Charles said, with a small clarification:

That should be "Dig your fire bowl down to one inch below the bottom of the hole in the tuyere."

I had a feeling this is what he was getting at. 

On 10/25/2018 at 11:10 AM, Charles R. Stevens said:

Perhaps this illustration will help? 

 

048ABDCC-1042-426C-9F43-D2700140E86F.jpeg

Unfortunantly many of the English smiths whose brains I picked when learning about sideblast forges aren’t here anymore. 

 

So, is the recessed area where the fire happens more gradually graded as drawn or with vertical walls like the guy in the video makes?

What’s the purple scribble in the bottom of the firepot?

So... even layer of cat litter on the bottom, pack the litter under the tuyere, then a layer of brick, the top of the brick in front of the tuyere will be the bottom of the firepot, stagger layer brick and fill with cat litter to within an inch of the top lip of the hearth pan. 

Do I install all of this clay cat litter dry or wet it down? If the latter, is that why you recommend water?

10 hours ago, JHCC said:

Forgot to ask: what were you using the caulking for?

The vertical sides of the hearth are not solid welded to the receiving angle. It had white silicone caulking (kind of) sealing it up, but it was just flopping around. So I pulled it all out of there and installed that refractory caulking. I caulked all seams within the hood and coated all of the TEK screws too. 

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