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Used Johnson Forge Furnace - Help with Choices

bois d'arc

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Last year I was buying a band saw from a closing machine shop.  This was an old-time, shop: the saw in question was made in the early 1900s and had been in this shop since the 1940s.  The old machinist was in poor health (I had not met him yet) and his son and I were negotiating and alternately discussing how to move the 800lb behemoth on to my trailer.  My rigging and strap helper on this trip was my 11 year old son.

After a while I heard my son whispering in a dark (dirt-floor) corner of the shop with and older gentleman.  I wandered over (ever concerned even in small town Oklahoma).  I noticed them looking at a gas forge and I hear the old man say; “I sold the anvil yesterday”.   I correctly surmised that they were discussing the forge.  My youngest son had been wanting to take up blacksmithing.  I have nothing against blacksmithing, mind you, but I have been encouraging my son to pursue certain other interests.  I provided programmable micro controllers to encourage him to tinker with the intersection of hardware and software.  I bought him a decent second-hand lefty guitar in case he wants to follow his older brother in to music as a hobby.  Be he has stubbornly maintained an interest in blacksmithing – reading the only two books in our library about the subject at least twice – asking questions about the melting point of metals, the possibility of recycling aluminum cans - asking about the Anvil Shaped Object (scratch and dent special from Wholesale Tool a few years back) in my shop.

Finally I realized that my son was bargaining for the forge.  The old man was obviously delighted to see a young fellow interested in mashing metal.  With no room on the trailer (some other odd bits followed me home as well), the forge got loaded on to the pickup flatbed. 



Now that it is warm again, it is time to make some decisions.  The Forge is a Johnson Forge Furnace model 122 Double Wide (I think – I wrote this down and then left the paper at home).  It seems to be plumped for propane and has a spark plug ignition situation (not kidding).

The forge is in OK condition.  Rust around the edges, a few chips on firebricks, and that’s about all I see wrong.  I know little about gas gorges but I have spent some time near a coal forge before.  My shop has neither natural gas nor propane service today. 

I would like to ask for comment on, and evaluation of our options:

  1.  Fix it up and use it as designed with propane.  I live outside of city limits and I could have a propane tank situated shop adjacent.
  2. Fix it up and convert it to Natural gas.  I have gas service at the house (about 100 feet away from the shop under a lot of cement driveway.  This seems expensive to plumb.
  3. Scrap it for salvage and build another forge with the components.  It looks to have a nice blower, lots of firebrick, some low-tech burners (they look a lot like holes in metal), a solenoid, a sturdy stand.  This could go coal or gas.

For my fix up options I was considering coating the bricks with ITC-100 HT, maybe filling in some cracks, maybe building up the top table to get a better seal against on the swinging cover.  Probably fitting a hanging hood over the forge to take away heat also.

I have only a vague idea what we will do with it.  The nice old machinist sent my son home with lots of steel (some giant old truck springs, etc).  We will probably forge up some knives and maybe a chisel or gouge, maybe even a froe (I could really use a big froe).

We are working toward an anvil and I ordered a $6 pair of tongs from a late night ending ebay auction.  Hammers, we have.  I buy the odd tool lot and I have a number of hammer heads that are cross peen smith type.  I can spokeshave out some handles this weekend.


My has modern metal and wood fab cabilbiites.  I am open to suggestions.

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Suggestion 1: add a general location to your profile so we can make suggestions that apply to your area!---If you were in the USA your local library should be able to ILL *tons* of books on blacksmithing.  Not so if you are in a different country!


#2 Johnson forges tend to be gas hogs, very sturdily built for commercial or school use.  You don't see a lot of them in hobby smithing as a home built propane forge that will run off a BBQ sized tank is *EASY* to build and runs quite a bit cheaper.

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ThomasPowers, on 02 May 2013 - 10:37, said:
Suggestion 1: add a general location to your profile so we can make suggestions that apply to your area!---If you were in the USA your local library should be able to ILL *tons* of books on blacksmithing. Not so if you are in a different country!

#2 Johnson forges tend to be gas hogs, very sturdily built for commercial or school use. You don't see a lot of them in hobby smithing as a home built propane forge that will run off a BBQ sized tank is *EASY* to build and runs quite a bit cheaper.

Suggestion 1: Updated, thank you. And, my bad, the library in question is a room in my house. We only have about five thousand volumes focusing mostly on ancient wood crafts. The nearby Tulsa City-County Library System has untold blacksmithing volumes available via Inter Library Loan.

#2 - Yes. I noticed the specs on the .PDF I obtained from the Johnson website. At first I thought they had added a zero to those numbers! This is actually what started me thinking about a conversion and/our rebuild.
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I used to live in OKC during the oil boom of the early 1989's; picked up a bunch of smithing stuff before the crash of '83.  Some of it I still have!


When we made the move from Columbus OH out to New Mexico we shipped 469 *boxes* of books; not a single bed, couch or TV set; just books and bookcases.  I have my research library and my wife has hers and then there is the shared mountain of books...


Can you get to a meeting or two of the 





Great group of people and seeing what people are using and how it works would be the best

method of deciding.  Personally I have a Johnson heat treat furnace/forge I bought for US$80 complete and have never used it.  I have built 3 other propane forges and use them a LOT!

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This group was not on my radar, thanks.  http://saltforkcraftsmen.org/Calendar.shtm


We will try to make a meetup.  I am working in Arkansas this week and I heard stories at lunch this week about an Arkansas knife maker who builds some tight but sweet small forges on the side.  I am going to try and take a look at one of those via a friend of a friend.


I always move the books and guns myself.  The movers get the rest.

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Welcome aboard, glad to have you.


I have a Johnson appliance 122a and have never hooked it up to anything. You can get kits, instructions, conversion parts, etc from Johnson. They're commercial units though and have commercial sized appetites.


Were I you , I'd sell it or maybe trade it for more useful stuff. The things are just too big for a hobbiest let along a youngster learning the craft. That said, they're superior commercial forges. reading your back story I was hoping you'd found one of the pedestal mounted square Johnsonslike we used in High school heavy metal shop. those are sweet units.


Look through Iforge, there's a forge section covering all the basic types, there are directions and plans for building gas forges from the ground up.


How about getting your boy to subscribe to IFI? Sure, we'll encourage him to play with fire and beat things with hammers but what could be better? He'll be making things a wood worker Father will b proud to use. Nothing feels so good as using a tool you've made with your own hands and I can only imagine how good it'd feel to use one your son made for you.


Frosty the Lucky

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Greetings  Bois,


Once you have a taste of metal work its a lifelong journey.... Encourage your son to continue...  Most/////  ALL blacksmiths are the most giving and honorable people you will ever meet.....   Find a local group and let him run..   Funny thing ... Most of the young students I have start well BUTTTT  after , they have a hard time getting any forge time in.  Yep Dad gets hooked..   My suggestions are as follows.


Keep the boy and cherish every moment...


Burry or dismantle the forge.  It will only eat up money and is more dangerous than smaller models...  You can make or purchase a small propane forge for under 300.00    Don't mess with junk..


Forge on      Jim     Forgot:  Also purchase a book called  A blacksmith Craft by George Dixon.... Best for starters

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Thank you all for the welcomes and the suggestions - I was hoping to get some experienced opinions just like the above.


I looked at some sample forges and two things in my "recycling pile" struck me.  One was a 20gal air tank off a junked compressor, the other was our old giant iron double sink. 




I will look at the exact model next time I am in the shop (its old enough to be green, not the new blue or the old, old blue).  I still has the plate.  My son would probably love it here but I have some old-fashioned rules about internet usage and such.  In a few years, you will see him on here.  Until then, he and I can co-post (he's at basketball practice at them moment).

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Mine is for sure a Johnson 122b DW made in Cedar Rapids, IA (My son and I will be in Cedar Rapids in a few week for Handworks 2013, BTW (http://handworks.co/))


I may keep it tucked away (just in case) and setup a small, efficient forge for now.  I can weld and grind (the way I weld grinding is very important...) so I am undaunted by most of the builds structurally - but the burners I would be buying.  I looked at a SISCO anvil in AR - a rough little 126 ponder with one messed up shoulder and bumpy horn.. 

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  • 2 weeks later...



The Johnson forge sits under a tarp still.

We have been reading books and cleaning/handling rusty old hammers..  "A blacksmith Craft" by George Dixon is a great book indeed - pictures are fair but the drawings and diagrams are wonderful. 

I located a rivet forge at my local antique store as a "planter".  I left them the pot and we will fire that up with some charcoal to practice our fire making one of these days (it had in-tack turning blower underneath that was simply missing the 1" leather belt and the ratchet/rocker setup.

I read the Mike Porter gas burner book once - I need to read it again (like the intro says) to let it soak in some.  We are going to move slow on building/buying a gas setup.

e send off our membership in the Saltfork Craftsmen.


Thank you all again.

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This isn't really directly related to your forge question, more towards your comment about steering your son towards microcontrollers.  I acutally built a couple of microcontroller based projects that are related to blacksmith work. 


My electric kiln is Arduino controlled:  it interfaces a thermocouple with a decoder IC, drives a little relay that in turn drives the 220v contactor for the coils, and has a plain text interface over the usb com port for programming ramps and soak times.  I mostly use it for annealing glass, but I'm wanting to heat treat stainless, and based on some pointers from folks on this site, it should work for that without modification.  The same control system would work for a heat treating salt bath, or maybe to control the temp on an electric start forge.


My pneumatic power hammer is running an Arduino as well.  The analog inputs on the Arudino allow pots to be used as a cheap way to control the stroke length and bias the hammer stroke to the anvil end.  I put a switch to go between recipocating and a single shot for striking tooling.  The microcontroller runs a shuttle valve that, once again, folks on here helped me understand.


I volunteer as a science fair judge, and have seen early high-school level kids turn engineering knowledge of similar interest into winning projects.  Metal casting, and stove building both wound up at the regional and state level.  While it is a primitive art at it's core, there is plenty of material science, industrial engineering, metallurgy, and physics that can be applied to blacksmithing.  I think Beagle Bone might be better, but If you ever want Arduino code, circuits, or advice, I would be glad to share.


- James B

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