After a long computer generated hiatus from the forum (Mr. Computer died) there is another computer in the house. The wife and I decided that we did not really need a computer, but the son upgraded to a lap top and brought his "old " computer down for us to use. He is a great kid, but he has ulterior motives that I will not bore you with.
Waaaay back in November last year I wrote a post that I never got to see the responses. Jr, you asked what part of Kansas I call home. I live about twenty miles SW of Topeka, not too far from you. To the folks that responded to my post, thank you very much for the leads, I will check them out, but I have not had time to play around with the topic of the post. I have been too busy developing a lust for hot metal!
I built my forge and I am rapidly learning the subtleties of the forge and to use what I have learned from here and the various books I have acquired. My primary interest is in welding and to that end I weld, test/destroy, cut off and repeat until I can now stick a weld that defies destruction nearly every time.
CAUTION I do not recommended what follows to the faint of heart or the inattentive. There is a inherent danger to maintaining what amounts to a continous explosion in a confined space. Using a liquid fuel may be a bit more dangerous because the liquid to vapor phase transition takes place in the forge rather than in a tank where the vapor boils off, however, if what follows stirs your interest and you decide to experiment with the big bang theroy in your universe, please excercise all due caution lest you be remembered by the neighborhood kids as Mr/Ms Supernova and by their parents in more...colorful terms? There is an upside to all this though, if all goes well you may not be around to suffer the embarassment of the arrival of strangely clad beings in big shiny trucks with pretty flashing lights. The same can not be said for those near and dear to you.
THE FORGE, Rev B: The forge is a freon tank the next size up from a 30# tank (50#?) It is lined w/ 2" of ceranic blanked(CB) w/ the inner 1" cut away at the bottom for a 2600 degree IFB. It is lined w/ 3000 degree refractory cement from McMaster. The refractory is not usable as received, too thick to apply to the CB, but I noticed that the separated vehicle in the cement was very similar to the vehicle used in latex paint. Since this was all experimental, I found an old can of paint the pigment had settled out and drew off the clear vehicle. I mixed this w/ the cement, lined the edges of the IFB with the cardboard from the back of a tablet,(This will burn out in the first firing leaving enough room to change the IBF later.) moistened the CB and brushed on the thinned cement.
THE BURNER: I use low volume high velocity compressed air to atomize diesel fuel for the forge. I looked at several options for fuel delivery to the atomizer, gravity: too dangerous, pump and weir: too hi-tech and I finally settled on building the atomizer so that it would have about 18"WC suction on the fuel line at 20 PSI on the air line. I did this so that, if things went amuck at the forge, I could shut the whole thing down by releasing the air line at the compressor, well away from the forge. I am still not satisfied with the fuel system yet, as the burner draws down the fuel in the tank the head on the atomizer goes up and fuel flow falls off a bit. I am thinking about the system used on the old kerosene kitchen stoves with the inverted glass jar feeding oil to the burners at a constant level. The idea of a glass, fuel and hot forge does not appeal to me though. Maybe a plastic patio torch fuel container? Hm.
BUBBLES BAD: Light off can be a bit dicey. There is an interval where the forge is hot, but well below the flash point of the fuel. A bubble in the fuel line at this time causes a flame out and the forge ceases to be a forge and becomes a BFWC generator. Immediately thereafter, a synapse in the part of your brain that deals with self preservation fires and it says, "Wait a second...that ain't smoke...that's vaporized fuel...probably pretty volatile." After a brief, but intense, period of activity, you will surely hie yourself by the most expeditious route to your place of domicile with a very odd manner to your gait and change your skivvies, thereby giving the keeper of said domicile cause for much mirth. Serioulsy, it is one thing to not see where the burnt gases from the forge are going, but it is quite another to see where the UNburnt gases are going...and how quickly they get there!
MOISTEN, NOT SOAK: My initial idea to light the forge was to use a small patch of cloth on a wire soaked in diesel fuel inserted in the forge. Like most initial ideas, it wasn't very good. The first time I lit the forge it was 12 degrees. Diesel fuel at 12 degrees has a certain viscosity. If you alter that viscosity by stuffing the soaked rag in a 2000+ degree flame, things change rapidly. The fuel drips down onto the rapidly heating IFB, the rag is burning up giving less surface area for the fuel, the forge is running heavy reduction, the rag goes out and then along comes that wee bubble, but by now all that excess fuel is burning outside the forge...lots fire, lots of flame. Okay, I'm not even making the trip to the house again! To solve the problem, I drilled a 1/2" hole in the burner and insert the flame tip of a propane torch into the fuel/air stream and keep it there until the flame has stablized and the forge is showing a little color.
DO NOT LISTEN TO THE LITTLE VOICES: Perhaps there is enough of kid left in me or it was just a matter of stupidity, but a little voice said, "Hey, let's see what this thing will do." The more mature voice should have said, "Let's don't and say we did.", but it didn't. I don't have any idea what the internal temperature of the forge went to, but at 27 PSI, the whisp of flames out of the forge took on a pinkish cast and any organic material closer than about 40" started to smoke in less than a second. Inspection after cool down showed the IFB destroyed and the refractory looked like it had a clear glaze applied over it and was badly cracked, but still adhereing to the CB. Replaced the IFB and recoated the refractory. The cracks will always be there, but it does not affect the operation of the forge and they pretty much seal up at temperature, yeah, pretty much.
GENERAL: All in all, I am very pleased with the results. A few minor improvements and I should get the fuel consumption down a bit more. The diluted refractory works very well and seems unaffected by borax and being banged about. It retains heat very well taking about 10 to 15 minutes to loose color on shut down. I had to rebuild the burner mount so it is removable from the forge, too much heat rise, it would boil the fuel in the atomizer. The major problem with the forge is too much heat. Welding heat is achieved at 20PSI and a quart of fuel per hour. Normal forging heat is about 15PSI and about .8 quart per hour. At the lower pressure the atomizer does not atomize very well, but that is a design problem based on a lack of knowledge on what to expect when I built it and is correctable. At welding heat the compressor cycles 40 seconds every 5 minutes and at forging temperature 40 seconds every 6 minutes.
I am not a fan of technology even though it has been putting beans and bacon on the table for the last 42 years. I took my little camera to the shop for some pixs only to find out the OS in the "new" computer does not support my camera. Well now, ain't that another technology "gottcha!" I will see if my son will bring his camera down for pix.
I hope this post okay, been a long time and not that many post anyway. Later. JD
