A Portable Side Blast

[j.w.s.]

I just wanted to share a simple construction project I built on Friday for some demonstrations I was doing over the weekend at the New Jersey Renaissance Faire. I'd been a little too busy with finishing up stock and thought I had a small portable coal forge ready to go, but it turns out as I was packing that my memory is not what it used to be and several key pieces had been removed and utilized in other building projects since it was last used a year a go. Anyway, I threw together a sideblast forge in about 35 minutes using just some scrap laying around the shop, some black iron pipe, a blower, some bricks and a little bit of sand. I've never built one of these before and I was absolutely shocked at how well this worked right out of the gate once I started paying attention to how the fire needed to be managed compared to my other bottom tuyere forges I've built and used in the past; of course if I had tested it before I drove it out to Jersey and fired it up for the first time, I wouldn't have been as shocked - but at the very least, I was right, it definitely looked like it would work. For the tue, I simply took a piece of 1.250" pipe and forged a nipple on the one end down to about 0.875". Welded some scrap together to make a damper, brazed it in line, cut a few pieces of angle iron to define the bed and two more support pieces that got welded to the base to hold the pipe and blower assembly. It's definitely inspired me to design a one for my demonstration forge at the Pennsylvania Renaissance Faire this year, something a little more permanent and probably with a water jacket for cooling. I'd only ever used a sideblast once before at a friends shop and that was only for a few minutes, but I'd really starting to appreciate the design and I think it allows for better management of fuel. Anyway, enough talk, here's some pictures:

-J

[Everything Mac]

Nicely done sir. 

 

I hope you don't mind me saying but I don't think it will win any beauty contests. But it sure works which is the man thing. 

 

I think the side blast offers a few advantages over the bottom blast - management of clinker mostly. A proper water cooled forge is a joy to work with IMO. 

 

Andy

[Frosty]

Well done -J. The only thing I might have done differently is to have made a trench to contain the fire. The one thing I would definitely have done differently is to make a little brick shield for the air blase. Just lay two bricks on their sides on with a gap the size of the blast opening and cover it with another brick. That way the fire is away from the pipe so it doesn't get damaged by the heat.

I shielded the piece of pipe in the funky field expedient forge I slapped together to repair a damaged long tong when clearing land for the house. I only had a piece to thin walled galvy pipe for the air supply between the 12v mattress inflater and the fire so I just dug a narrow trench and covered it with a piece of scrap. If I'd dug a longer trench I could've done away with the pipe all together.

That looks to be a perfect Renn fair setup. Did you have a good time?

Frosty The Lucky.

[David Einhorn]

I built two side blast forges, both are my attempts to reproduce mid-1800s U.S. military one Army and the other a Naval forge.  For the Army forge, I used reprints of the period diagrams the army gave to factories to produce the forge.  The diagram is the official government drawing of the "Airback" at the rear of the fireplace.

 

 

 

Edited May 27, 2015 by David Einhorn
Add drawing of airback

[Charles R. Stevens]

Thanks David, have a question for you on that point, i have notused the english versian of the travaling forge apears to have a shollow bowl in the fire pan just infront of the tweer, I dont remember seing any such on the US versian. Did i miss i

[j.w.s.]

Lol, thanks guys.. again, I had an hour until I needed to be on the road and this was just salvaging parts I already had around the shop. While I've never built a side blast before I understand the principles and for less than 40 minutes of work this is what I came up with.. it does indeed work well and has convinced me that I need to build a proper one soon because I really like it. It's also a great example of how to build a forge with scrap metal just laying around. There's also a space between the two bricks hugging the Tue that was partially filed in with sand to create a channel to direct the air flow. And Frosty, i had a lititle fun but after 20 years of working this particular genre of show I definitely a little more green in my pocket to totally smile, lol, we'll see how the next two weekend's go and get back to you.

J

[Frosty]

I must have missed something. What's improper about this one, it works doesn't it?

Frosty The Lucky.

[j.w.s.]

I must have missed something. What's improper about this one, it works doesn't it?

Frosty The Lucky.

Not improper.. perhaps I should say next time I'll take my time and think out the build a little more before just jumping around welding this n that, brazing that there and reducing the end in the forge to about so..  nope, she works beautifully, welding heat is easy to attain.. and I can now see how a little more planning would make this my go to coal forge.

J

[Frosty]

Ah, I was funnin you. What I really like about this build is it shows how little hand wringing brain work is necessary to make a perfectly workable forge. You could've used a wooden box just as well. A bellows would take longer but if the period police allow an elec blower why the heck not.

Frosty The Lucky.

[j.w.s.]

Ah, I was funnin you. What I really like about this build is it shows how little hand wringing brain work is necessary to make a perfectly workable forge. You could've used a wooden box just as well. A bellows would take longer but if the period police allow an elec blower why the heck not.

Frosty The Lucky.

I don't know about a wooden box with this particular setup. Day 1, I was running it hard and caught the table on fire underneath. Lol that's through 1 9/16" brick, 3/16th sheet and being raised 1/2" above the wood table using drywall screws as risers. talk about a surprise! I flipped the table, put out the fire and left the whole thing upside down and placed the forge on the 2x3 legs of the table - then all was right with the world! I wanted a better insulating brick but the particular home depot I found in jersey had 0 fireplace supplies - not even refractory cement patch! Now that I'm back at home I'll cut some 3k brick down to the right thickness and re line it Saturday morning. I suppose a layer of kaowool  (ive got a lot of scrap pieces) and clay would work just as well.

J

[Charles R. Stevens]

Aluminum sheet works as well, a full sheet pan upside doun on top of the table so there is air space between the table and the forge will reflect 98-99% of the radiant heat. (Shiney aluminum at 99.+ and aluminum oxide at 98+) 

[David Einhorn]

Thanks David, have a question for you on that point, i have notused the english versian of the travaling forge apears to have a shollow bowl in the fire pan just infront of the tweer, I dont remember seing any such on the US versian. Did i miss i

​In U.S. versions of wheeled "Traveling Forges" the fireplaces are flat because of wooden members under and on all four sides of the fireplace.  There is a slight air space below and on all four sides of the fireplace for the mid-1800s Army Traveling Forge to prevent the frame and stock of the forge from catching fire.  An indentation in the bottom of the fireplace would likely cause the hot metal to contact wood. I reexamined the drawings of a mid-1800 British Traveling Forges,  the semi-circular indentation in the fire pan, yes that appears to be part of the design of the British Traveling Forge.  The indentation is possible because the forge is in the rear of the forge, and the wooden frame is only on the sides of the fireplace and no part of the wooden frame is under the fireplace.   Because the fireplace is in the front of the mid-1800s U.S. forges, there is a heavy wooden member less than an inch from the bottom of the fireplace.  That is because that wooden member is necessary to pull/attach the Traveling Forge to the limber.  There is no wooden member under the middle of the back of the Traveling Forge because nothing is being pulled by the Traveling Forge.

 

 

 

Edited May 27, 2015 by David Einhorn

[j.w.s.]

Aluminum sheet works as well, a full sheet pan upside doun on top of the table so there is air space between the table and the forge will reflect 98-99% of the radiant heat. (Shiney aluminum at 99.+ and aluminum oxide at 98+) 

Good to know.. I just don't happen to have at 25x18 aluminum sheet pans lying around, but I'll save that idea for the next time I'm in a pinch!

J

[Charles R. Stevens]

Thanks David, i appretiate your responce. It apears that we have a distance of aproximently 4" from the tweer to the botom of the pan in the Us forge?

j.W.S, misplaced streat sighn?! Just kidding dont want any one busted for stteling public property or endagering the public, lol. But aluminum sheet with as little as a 1/4 inch on both sides can save yiur butt. Thats how wood and coal stoves are instaled in boats. Tho i think its 1" on the fire side and 1/2 on the wood side in standard practice (dont quoat me, been A wile sense i looked in to that for sheep camp and vardo instalations) But for a forge set on a table, it would cut down on weight, and is cheaper than koawool. As to the sheet pan, one will be surprised what you can find at a restraunt supply that can be reperpused, tho the thin sheet at your local box store is probbably cheaper.

[j.w.s.]

I've got a cnc plasma table and a company that sells 1/4 aluminum sheet right down the road, I can handle this.

 

-J 

[Frosty]

I've got a cnc plasma table and a company that sells 1/4 aluminum sheet right down the road, I can handle this.

 

-J 

​Goodness, just smooth 2-3" of dirt under the pan and the table is safe. For a wooden side blast forge the box needs to be deeper so you can ram 3-4" of dirt, clay, etc. in front of the tuyere for the fire to burn on.

Mineral soil is available almost everywhere so you can empty the forge for easy transport. With a little imagination you can have a hinged/removable lid that serves as a table next to the forge but closes all your tools in to pack. Oh heck, the lid could break into two halves to make the bellows or perhaps make legs or . . .?

Complex is not a sign of sophisticated technology, the simplest tool that does the job well is the higher tech. For many things, our ancestors were much more sophisticated, look at the Mastermyr kit. That's a complete blacksmith shop plus materials and finished products in ONE, man portable chest.

Frosty The Lucky.

[BobMc]

Thanks for posting this.

It is reassuring to see that a forge along these lines can work well, since I have materials very similar, and I need to make a simple one to get started.

 

Bob

[Charles R. Stevens]

once you get the basics down its hard not to make a funtinal forge. But be warned each fuel and forge type has its own perticilularities of fire management and how big a heat zone made. 

Still working iut thow thick to go under the tuyere, but 2" of brick (to keep you from digging to much of the insulation layer out seems prety standard, 1" or so to the botom of the tweer (deaper for the water cooled ones with a 5" face, say 2". 3/4" to 1" black pipe for a tuyere and about 3" above the tuyere to the center of the heat zone (that is for charcoal and small coal fires) a chart was posted in a thread about "cfm for coal fires" buy Glenn that relates tuyere size to deapth of fire with coal. Charcoal with a single tuyere only gives a 4-6" heat zone, with a side blast, but unles you have a power hammer you cant forge much more than that. Been looking and experimenting with this sence Christmas.