The Start of My Coal Forge

[Henry Lockley]

I’ve been building my first “proper” coal forge these past few weeks. My past attempts have consisted of quickly made badly designed forges, one of which was a cut open beer keg with a brake drum in the middle and a few bricks to add height to the pot. It could heat metal ok but the fire pot design meant that if I tried to heat a length of steel up it would melt the end of and it would not be possible to heat the middle of rod up. A while back on eBay I saw for sale 12mm steel sheets 1500mm by 500mm for £20. I bought four of them to make benches with but I thought I might aswell build a good forge with them. So far I’ve fabricated a forge pot, dimensions 12 inch by 10 inch, and the pot seems massive. The depth of pot is about 4 inches. Is this pot too big? Adding to that, will my pot need more steel cutting from the bottom to add air flow. I have a few slits cut but I’m debating if it’s enough. And, is my pot mounted correctly to the plate. I intend on having a beer keg with a hole cut in the side to be placed next to the fire and have a side draft chimney. Also, how high should I mount my forge, anvil height? Anddddd, how tall, wide should the chimney be? Sorry for the questions, don’t want to mess up my forge build. I’ll burn standard house coal not coke, if that helps. Hopefully my photos are okay, if some of these questions are already on the forum I apologise, I mainly want to know if what I have to so far is okay but I might aswell ask about the chimney and height for when I get to it.

Many thanks for your time, Henry.

 

[JHCC]

Looks like a good start. As for the size, the question is always "Too big for what?" In other words, what kind of work do you plan to do? If all you're making is nails, this would be too big. If the smallest stock you use is 30" square, it will be too small.

I kind of like your air slots, and they should be fairly easy to clean out just by sliding the point of your poker around them. You may have a problem with them burning out over time, though. Don't enlarge them for now, as you'll get coals falling through if you do. 

[Henry Lockley]

I am hoping on doing really anything, not that it answers the question. Knives, pokers, punches, small axes, tongs as I have none. I want to get it right so in a months time if I want to try making Damascus I won’t need a bigger forge. I’m debating if 12mm will last long enough, it’s not going to be a full time thing but if it ends up turning into that I hope it serves me well. What height should I have for the forge?

Thanks for the reply.

[ThomasPowers]

I like my forge such that If I am holding a piece of stock it is at a good working height and I do not need to lift or lower the piece  going to the anvil.

[Henry Lockley]

So, I’ve done abit more to the forge. I’ve welded in the fire pot and welded up the legs. What I plan on doing next is welding abit of 5 inch flue pipe to the bottom of the forge pot, it’s already a T shape so that should be fine. Now, my plan on a chimney is a beer keg with a hole in the side next to the fire pot to work as a side draft chimney. I’ll obviously have to connect the beer keg to a big chimney but will this work? I have a few photos below to hopefully explain my plan. 

Thanks

[ThomasPowers]

You need a rim to keep coal from falling off the table.  Some lengths of angle iron will work and can be held on with c clamps to make re-configuring easy

[Irondragon Forge ClayWorks]

The beer keg may work or melt. I would suggest building a "super Sucker side draft. They work great and are simple to fabricate.

 

[Henry Lockley]

Well, it’s more like the end of my coal forge. The blower is fitted and has a crude but functional air gate/controller however at some point I’ll have to buy a voltage controller thing to really control the power. Other than that and the fact the legs need to be shortened I have finished the forge aspect but now we get to the chimney. I’m thinking of opening up one side of the beer keg and having it as a side draft, the keg is around 2mm and 318 stainless, so it should be okay. How big should the opening be to let the smoke go through on the keg? And, what width/height should I go for with the chimney flue pipe? I’ve got about 3 or 4 metres of 6 inch pipe but I doubt it will be big enough to function well. Please excuse the dire welds on the forge I was kind of rushed.

 

[Irondragon Forge ClayWorks]

Looking good... I was thinking aluminum but the stainless keg should work for a side draft with a 10 inch flue pipe. The super sucker box has a 10X10 inch opening. If you may be working with long stock a couple of cut outs on each side  (like the front) will allow the stock to get into the fire.

[Henry Lockley]

Yeah I’ll cut some V slots in the sides. How high should the 10” chimney go to work well

[Irondragon Forge ClayWorks]

That depends on where the forge is located. Outside about 6 feet will do, in a building through the roof at least 3 feet is how mine is but you have to figure more height for roof pitch and how close it is to the peak.

[Henry Lockley]

Well I’m yet to build the shed for it lol I’ll get around to it one day. I have a hydraulic press which the shed will get build around. I wanted to make a forge capable of heating big stock which can get be used in the press. Hope to make stuff like axes and custom work one day. Here’s a photo of the press

[Glenn]

Fuel does not make a fire hot, air makes the fire hot. 

I would suspect that the blower is way more powerful than you will need for the forge. You will realize that when you light the fire and then blow the fire and fuel into the air above the forge.

Disconnect the blower from the piping and leave a air gap, say 4 inches, between the two. Aim the blower more directly at the opening for more air, and not so directly at the opening for less air.

[Henry Lockley]

You are right, the blower is way too much for the forge. I know because the brake drum forge I had before had a 2 foot flame from the coal because it’s too much. It’s a bouncy castle blower. I thought having an Air gate would remedy it but even fully open it’s still too much. And it’s noisy. I hope to put a voltage controller on the fan to really tame it.

[JHCC]

So, your only means of controlling the blast is opening the ash dump?  Yeah, that’s not going to do the trick. Either follow @Glenn‘s recommendation above or install a gate valve between the blower and the tuyere. Both methods will work just fine. 

Oh, and get some ear protection. 

[Mark Ling]

Yes, bouncy house blower is too much, I used to use one with a coke forge, and it was too much (and coke needs more air than coal too). If you are willing to spend about $80 on a blower I know of on I can PM you the link, its one that I use, and is the quietest but good quality blower that other smiths I know use and have no complaints, eventually I would look into it if I were you, I understand that may be a bit much right now to spend on a blower. But for now a hair dryer will work too, just a simple $5 one(if your feeling like even paying that much, typically can get them for less at yard sales).  Or do there suggestions, it's just that a bouncy house blower is really really loud (as I'm sure you already know). I remember when I had it I had to shout to people for them to hear me.

                                                                                                                                                         Littleblacksmith

 

Admim Note: LBS contacted me and this is a Fasco B24220 115 Volt 135 CFM Centrifugal Blower 

I will remove the requests for the information via PM from LBS.

[Tommytaptap]

Henry. I too have the same blower as yours. I don't know the technical details but I am given to believe that the motor in it is not one you can alter the speed of. I loosely fitted with one small bolt, a piece of Perspex to the induction grille side of it and that reduces the airflow somewhat by pulling the Perspex towards the grille. That combined with leaving a gap as described gives a much more reasonable flow. Tom.

[Tommytaptap]

Henry Don't know if you've looked at the link supplied by LBS but the company don't ship to the UK which is a shame. However, all is not lost. I have also been looking for a pukka blower and came across this one on Ebay UK. Called a Bahcivan 140.60 theyre on sale in Germany for around £80 incl postage. They are even open to best offers on them! They are made specifically for blacksmith coal forges. They also sell  potentiometers to vary the motor speed. Sorry don't know how to bring a link here but check out ebay-just type in bahcivan 140.60      . Tom.

 

ps- managed to attach a picture of it!

[JHCC]

Squirrel-cage blowers tend to be a lot quieter, too.

[Henry Lockley]

Tonight I tried the forge out to see what needed to change. I need to cut deeper slots in the angle iron so long rods are lower down to the forge pot. The blower is toooo powerful, with the ash pan thing at the bottom fully open it still is too much and it’s so noisy. Before investing in an expensive blower, I hope to try and fit a voltage controller to lower noise and make it more tame. Other than that the forge is perfect for me, I can heat up so much more steel stock than with the old brake drum forge, which would only do ends of rod and melt the tip off. I am pleased with what I’ve done, I’m 17 so when done with the full time IT course at college and the night time welding course I hope to make this more than a hobby and have something profitable. I’ve got a shed to build which will be the next project for me but I have one last question. For the chimney, I intend on using 10 inch aluminium spiral tubing for the flue pipe. Is this going to be okay or am I missing something. Obviously it won’t rust but will it last, as steel 10 inch pipe is eye watering expensive and money is tight with my part time job. It’s only cost me £20 to build the forge so far, the fan and angle iron was lying around only had to pay £20 for the 12mm steel sheet. 

[JHCC]

Aluminum has a tendency to melt if it's near the fire, so no, not recommended. Take a look at some of the threads about flues, especially the "Super Sucker" design. 

[Henry Lockley]

It will be on top of a beer keg which is stainless if that makes a difference, will the heat of smoke and hot gasses still damage it?

Thanks

[AggieBlacksmith]

Hey Henry, just reading back through you thread and I saw that you said your sheet metal only cost you about $28. Could i ask where you bought it?

[Mark Ling]

I think that's about what it costs for a 4x4' sheet of plate from Bryan Iron and metal for 1/8" though its actually a little cheaper, though its been a while since Ive bought any. If you are wanting 1/8" plate I know some one who has an over abundance of it that he would maybe sell too here in town.

                                                                                                                                                            Littleblacksmith 

[Henry Lockley]

I found the steel locally in the area which someone was selling. It was on EBay, collection only here in the UK. Looking back it was a bargain, I’d imagine to buy it new would cost at least £200, per sheet. I did pay £20 per sheet, each being 1.5 metres long and half a metre wide. It’s  made some fantastic benches and the forge which I built.