Tue Iron Help.

[Alan Evans]

The Baffle after speaking to a couple of people it was mentioned that a baffle ( or some flat welded sideways onto the air pipe would help the water convect ....An  inlet and outlet to an old header tank is a great idea save a lot of work

 

Thanks for replying 

Jez

 

More of a cooling fin than a baffle then?

 

The heat source is up against the end of the tue rather than the air pipe so possibly concentric rings welded onto the back/inside surface of the end plate would be more effective for heat exchanging. The only part of my home made tue that burnt away was the end of the air pipe which I had stupidly projected out of the end plate and put a fillet weld around, of course that became the hottest part and was eroded. Your drawing shows it flush so should avoid that problem.

 

However I would still go for a dry bottom blast set up!

[lupiphile]

Hey There, all. Not to derail the topic but I can't resist picking all these productive, coke-using(addled?) brains (that sounds a little off,huh?) especially after the mention of using a bottom blast for coke.

[lupiphile]

to continue( Iforgeiron  dissapeared the rest of the previous post,) 

 

I'm using coke in a bottom blast. It's a fairly large, deep (6")fire pot , and I'm havingoxidation issues, Also and more pressing , with a bottom blast I've found my coke, being rather crumbly, has all this debris that gets blown all over the metal, and whist it make for some nice surface texture , it makes forge welding an impossibility( or lap welding really, any weld wherin I can't but help expose the scarfs to the burning fuel, faggot welds work fine) It's not clinker, I can tell the difference when that happens. I've been sorting the coke to keep the larger pieces out of the fire pot. Has anybody had this type of problem? Being in the states I don't know anyone else who burns coke exclusively. I am a professional smith and I'm in the middle of a largish ( I hate saying large in the company of Alan Evans, You sir, are an inspiration) gate with abunch of forge welded elements and this is proving to be a bit of a wall I've run up against.

 

I even tried making  a different fire pot. Have y'all seen the lillico book, blacksmiths manual illustrated? with all the steam hammer tooling? in the beginning it describes a type of forge they call a "pot fire"  wherein the fire pot is a 18" deep 12x12" box with the blast coming in from the side and the tuyre  flush with the side wall. the tuyre sits about 12" inches below the top of the forge. So I built a scaled down version as I'm not a railroad shop at the height of the industrial revolution. mine's made out of 1" plate and about 8x8" by about 9" deep. It makes for a nice controlled fire, with a lot less oxidation, given my inconstant sized coke but the crumbles still manage to pollute  the working surfaces of my metal, still making lap welding extremely difficult. 

                      Thanks in advance for the help.

[Jeremiah Johnson]

More of a cooling fin than a baffle then?

 

The heat source is up against the end of the tue rather than the air pipe so possibly concentric rings welded onto the back/inside surface of the end plate would be more effective for heat exchanging. The only part of my home made tue that burnt away was the end of the air pipe which I had stupidly projected out of the end plate and put a fillet weld around, of course that became the hottest part and was eroded. Your drawing shows it flush so should avoid that problem.

 

However I would still go for a dry bottom blast set up!

RE Bottom blast ... I wasn't committed when you first mentioned it ... But am now Back plate is Made  .. and Think walled pipe scrounged .. after the research. I want to see this through and see how it works. I have always been a "Doer" rather than a thinker ... but this has made me sit back and think and i am rather enjoying it. ...Jez

[Alan Evans]

@ mainly Jeremiah 

 

Well I have to admit that I went onto the bottom blast in part because the 5 gallon oil drum I was using rotted away and in part because I acquired a power hammer and wanted longer length heats. If you're starting out and going to be mainly using hand hammer then a back or side blast with a  "swan's nest" fire is probably the most advantageous, have a look for the thread earlier where John B and I shared ideas with OllyO,  I posted a sketch of the hearth layout.

 

http://www.iforgeiron.com/topic/28704-alcosa-forge-dimensions/page-3

 

@ Jeremiah and lupiphile

 

The bottom blast I made is not like any other I have seen. It consists of a sheet metal rectangular funnel underneath the hearth which the air blast fed into, there was a counter weighted drop out at the bottom for the ash. Mk I was a  piece of flat 12mm (1/2") plate sat on top of the funnel and had a double row of OA torch cut holes running along like a domestic gas oven burner. I plunge cut these with the torch and discovered they were tapering holes larger on the side I cut them from, so I flipped the plate to put the small size on top so if any crud got into the hole it would fall right through. Mark II I fabricated from some 60x30mm (2 1/2"x1 1/4")bar set on edge with a 3 or 4mm slot between. I will measure it when I am at the forge next if you're interested. It was from rubbish lozenge shaped bar so I again used the angle to form a tapered slot for the crud to fall through. I  manage to get a 500/600mm (20/24") heat with it and if I want a short heat I just drop a couple of bits of plate over the air blast slots. I also made a couple of banana shaped chumps which enabled me to contain the fire if  I needed to reduce the spread and increase the depth of the fire (back to the swan's nest) for fire-welding or punching.

 

The fire is kept not very high generally, nothing like the Lillico fire pot, the bananas are only from 50mm (2") square I think. 

 

I seem to remember that the Lillico pot was a heat source and that the workpieces were set on the ledge around the fire rather than in the fire itself, I have a couple of amazing Italian films of shovel and bucket forging with a water wheel powered hammer which uses a similar ledge type enclosed fire/furnace.

 

So as far as the stuff getting stuck on the joint surface it sounds from your description like there is not enough breeze/ fire-heart between the air blast and the workpieces, but with a 9'depth there should be plenty. Are the workpieces being heated in the flame above the fire or in the fire itself? You are not just burning a small fire in the bottom of the box are you? The coke is not spitting is it? If it is try and bank it up around the fire so it will dry out before use.

 

Try making up a fire plate and dropping it on top of your box and see how you get on. Use the box like my funnel. I found using the blanking plates and bananas useful to contain the fire for lighting and then when it was under way make the fire shape I needed by adjusting the loose bits.

 

My final confession is that I have not lit the coke fire for 7 or 8 years, I have made a number of gas furnaces and they are all I use now. The last time I lit it was to show a student how to fireweld!