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I Forge Iron

New sideblast forge build


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Almost done with an Aspery style sideblast forge; have a handful of remaining unknowns:

1: I've got a hacked-up clothes dryer fan for an air source, it produces somewhere around 1.5 - 2 water inches of pressure; I have no idea if that will be enough.  The tuyere center is 1-1/4" black iron pipe sleeved in heavy wall 4"pipe.  I'm going to feed the air via a 2-1/2" blast gate and same size corrugated dust collection hose.  I guess I will find out, and upgrade if necessary.

2: I don't know what to fill the forge pan with.  I plan to lay brick in the bottom just because I have a bunch, and it is easier to deal with than sand or dirt, but on top of that, I don't know whether to use sand, soil, wood ash, coal ash, or if I can get away with just dumping fuel in like it appears they do in England.  I think they use coke, though, which may make a significant difference in not having runaway fires.  Opinions are welcome on this.

3: I will need to cut side reliefs in the tub wall for a pass-through, but I decided not to do it up front, because I don't know where exactly the heart of the fire will be, and I'd hate to do it twice.

I live in Maine, so I will fill the tuyere tank with plain old green antifreeze so I don't have to worry about freezing.  Both tank and forge pan will eventually get sheet metal storage covers to keep wind-driven rain out (I forge in a lean-to, no walls)

Currently, my pile of bricks forge has no chimney at all, and so I'm going to do a little futzing with smoke guidance; not sure if a side-draft or a hood will work best for me.  I'm loath to cut a hole in the tin roof, and then I would have to figure out how to keep rain out of the forge pan.  More to follow on that.  Having no walls makes this somewhat less of an issue.

Edit: All in, this cost slightly over $200 for all the steel, and another $12 for the can of Rustoleum hammertone.  Also used up a $40 Freud ferrous cutting skilsaw blade to chop the steel plate.  If I did this right, this looks like a viable alternative to very expen$ive cast firepots if you have access to a welder.  Also, had to stop a buy a new bottle of C25 part-way through, and grind the bit of bubbly weld out.  Oh well.

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Edited by hikerjohnson
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  • 4 weeks later...

Time for an update; this forge is fantastic, and everything I hoped it was going to be. 

I'm learning to control the fire size using water, and how to build a very deep fire with green coal banked around the sides.  The top of the fire will be three or four inches above the level of the table, for a fire depth approaching 8 inches.  Because of this, I am very far from the tuyere, and consequently, my work is not so prone to burning as in a shallow fire where you are very close to the oxidizing zone.  All I do is shove sideways on the green coal, and it pushes coke into the fire, and green coal into the coking zone. 

The dryer fan has plenty of ooomph, and for ordinary work (less than 1") I don't need to open the blast gate more than 1/8 open.  Full open will throw the fire fleas against the tin ceiling.  I got the blast gate at Woodcraft; it is for woodworking dust collection, and the hose and adapter too.

At the time of these photos, I was using bricks to take up volume in the table, but I've found that with enough wetting of the coal, I can take them out and just leave green coal all over the table.  

When I'm done for the day, I made up a 16GA cover for the table.  I rake out the fire, let it cool a little bit, and then slam the lid on, which snuffs the fire pretty well, and keeps the coke bone dry for next time.  All the water I use on the green coal seems to evaporate from the leftover heat between uses.

The tuyere cooling tank is only about half full of automotive antifreeze (50:50) and gets warm but not simmering in use.  Come summer I will likely add more antifreeze.  I've made a wooden cover for it to keep the fly ash out.  So far, no detectable wear on the tuyere tip in five or six hours of running.  I used antifreeze so I would have a year-round forge.  As you can see, it gets nippy here in Maine.

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Ash and slag were the classic fills. Sand is a pain as it is silica, just like slag, in fact it’s the sand in the peat that became coal that create slag. Cheap cat litter works, but I can’t say as how it will react to water used for fire management. 

Please cover your bosh sooner than later, cats in particular are susceptible to poisoning buy investing antifreeze it’s a neurotoxin requiring timely intervention with an IV of everclear. Animals are attracted to the sweet smell and taste. 

Fine looking forge .

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Where are the slots on the side for working the middle of longer stock lower in the fire?

CRS, I can see a hardware cloth cover for the bosch to keep small mammals out; So he seems to be aware of antifreeze being an attractive toxin for animals.  (My daughter the Veterinarian thanks you!) I might suggest a more positive fastening system for it as some animals will work at getting to the dangerous stuff!

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Thanks for the compliments and feedback; to answer a couple points and suggestions, I have fitted a nice sturdy (and heavy) lipped wooden cap for the bosh - I fitted it first with a mesh screen, which you can sorta see in the photos, but immediately saw all the fly ash sprinkling into the tank, so I decided a solid cover was in order.  This may also help reduce evaporation of the water portion of the antifreeze.

The fill in the pan is slowly becoming ash, and as it builds up, I am picking out the bricks.  I just didnt have four or five cubic feet of coal ash to start off with, so the bricks made a handy filler - I have a pile of them around for various jobs.

I haven't cut slots in the side yet for two reasons.  One, I wasnt sure exactly where the heart of the fire would end up, and so didn't want to do it twice, and the second reason being that I wanted to keep the walls as solid as possible for when the lid (not pictured) goes on - it's not airtight, but it's close, and so smothers the coals very quickly.

Additionally, I am now not so sure I really need the slots.  In these photos, the fire (the very first lighting) is quite shallow, and so prone to burning steel.  Since this photo, I've learned I can build a tight mounded fire with green coal banked and wetted on the sides that is very tall, probably 4" above the forge sidewall.  This means that at least for smaller long stock, I can put the bar straight across and have it in a pretty good place in the fire.  I'll still eventually cut slots in the side.  Just haven't gotten to it yet.  I am waiting for it to be warm enough outside to do the touch up painting where I cut.

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