hammerandtongs Posted January 14, 2007 Share Posted January 14, 2007 Hi there all this is my first thread so here goes. I burn 'Forge Breeze' Coke nuts on my air blown coke forge. I have the problem that after a days forging I have noted multiple tiny pitt marks on my house double glazed windows. I know this is definately caused by my forging activities. There seems to be minute red hot spits in the exhaust from the forge which are still hot buy the time they settle on a nearby house window(situated some 10 feet away) I have a relitively small back garden and so I think I increase the distanced of 10 feet to say 15 feet max. I dont at this stage want to make any large investment in a propane gas forge as I love to work over the hot coals so to speak. Can anyone out there give me some advice on a way around this problem, I would be willing to try a different coke but to be honest I get a good heat from this coke product and although there should be alternative coke I like the performance and burn of this one. My forge has a cylinder type fan blower which is a recycled extractor fan from a fume cabinet which was reclaimed from scrap.The air enters through a 2.5 inch steel pipe in a side draught direction into the coke fire. Any advice would be very greatfully recieved.Many Thanks H&T Quote Link to comment Share on other sites More sharing options...
Mike Turner Posted January 14, 2007 Share Posted January 14, 2007 Are you using a hood? If not increase your distance from your structure. If so you can put a piece of hardware cloth at the top of your chimney. Quote Link to comment Share on other sites More sharing options...
Ron Hicks Posted January 15, 2007 Share Posted January 15, 2007 Maybe you are using to much air blast? Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 15, 2007 Share Posted January 15, 2007 That same type thing is caused by grinding sparks so you may want to aim the grinder another direction if that is the reason. If you have an open forge, try a chimney. If you use a chimney already try adding another section to the chimney to make it taller, and a wire screen at the top. An air blast that does not blow the coke out of the fire pot will go a long way in reducing hot sparks up the chimney. This may mean building a deeper or even larger fire than you have now. Photos of your set up will go a long way in explaining the problem. After we see what we are dealing with, we can be more specific with our suggestions. Quote Link to comment Share on other sites More sharing options...
hammerandtongs Posted January 15, 2007 Author Share Posted January 15, 2007 Hi Glenn.Thanks for your reply here are 3 pics of the forge (as you can see a home made one) this shows the hood which is about 20inches above fired coke area.Hood measures 22 inches width by 17 inches depth .The forced air enters from the side via a 2inch diameter steel pipe. The fire area is sourounded by soft fire bricks as shown. I use these to contain the heat when forging knife blanks. Hope this will sheds some more light on the problem.:confused: I thinkk the volume of air delivered may be a contributing factor-may also need to throttle this down a small amount. Any more ideas guys. Many thanks in advance H&T Quote Link to comment Share on other sites More sharing options...
Ron Hicks Posted January 15, 2007 Share Posted January 15, 2007 Is your pipe blowing air across the top of the fire? Not sure on side blast maybe the pipe should be in the lower 1/3 of the fire & angle down? Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 15, 2007 Share Posted January 15, 2007 Reduce the air pipe from 2-1/2" (that is HUGE) to 1-1/4" in diameter (use another pipe). As Ron suggests, place the pipe maybe 1-1/2 to 2" from the bottom of the forge then add fuel to a depth of 6-8" above the top of the pipe. You do not need all the air that the blower can produce. Disconnect the air pipe from the blower and then just aim the blowers air blast toward the air pipe. You can adjust the air stream to miss the pipe and there by reduce the amount of air going to the fire. Just be careful that the excess air does not blow onto the forge as the air currents can cause additional problems. Blueprint BP0238 is of a side blast forge. I now lay the brick flat rather than on edge as the depth was not needed. Also look at Blueprint BP0232. You have what appears to be 4" aluminum dryer vent for a chimney. See if you can find some 6" or even better 8" diameter stove pipe and about 6 feet long. This may mean cutting the opening in the top of the hood larger to accept the larger diameter. If this forge smokes (all the smoke does not want to go up the chimney) cover both left and right sides between the hood and the forge. With a deeper fire you will need less air to get the heat you need from the fire. The first image will give you an idea of how hot things can get in the middle of the fireball, and the amount of flame that is seen on the top of the fire. Remember that this has been burning a while and is at working temperature. Keep us updated on your progress. Quote Link to comment Share on other sites More sharing options...
bruce wilcock Posted January 15, 2007 Share Posted January 15, 2007 Alcosa forge co used to make a patent grit arresster hood and they were very eficiant for use around straw stacks and timber yards untill recantly i had one , the idea was simple the flue was sq with a inverted V that divided it into two sq tubes one down each side of the hood and fitted with a slide out door at the bottom to clear the grit ,and there was some, above the ve baffle the flue opend out to about twice its size for about 1 ft and had another downwards facing baffle that brought the flue back to the original size the idea of the bulge in the flue was to let the gases expand and lose speed letting the grit fall back , it was far more simple than it sounds . As to the blast you have on it could be a bit stiff ,but some of the forges we ran on big jobs the coke was boiling and the grit up the flues had fire in them ,the arresters did a good job . This is landing up a essay, the men that ran Cupolas had big troubles and they had to sort it out with baffles and reverse flues ,i have a forge we used for anchor forging and i have made a baffle hood for it ,stand outside your smithy with the hearth at full blast on a dark night and you will know if you need a baffle box . Quote Link to comment Share on other sites More sharing options...
irnsrgn Posted January 15, 2007 Share Posted January 15, 2007 yup too big a pipe into the forge, and you can adjust the air by adjusting a piece over the intake of the blower, show a picture of the blower please. Quote Link to comment Share on other sites More sharing options...
hammerandtongs Posted January 16, 2007 Author Share Posted January 16, 2007 Hi Ron-Glenn-Bruce-irnsrgn, Thanks for your replies and advice Guys .There seems to be a number of improvements I need to make,not least of all to reduce air volume and blower inlet pipe diameters. The chimney size increase in diameter will increase the updraft I guess- good call. Thanks for the photos and illustrations really good and gives me an idea on whats probably gona need some mods. I had not thought about an arrestor in the chimney will do some more research on this. Great advice gentlemen ILL KEEP YOU POSTED ON HOW i GET ON. You know what this means-Now Ill have to make a visit to the junk yard to find an 8 inch diameter chimney from the fabricated heap -air duckting.: Cheers Guys H&T. I will post a picture of the blower soon as I take a picture of it. Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 16, 2007 Share Posted January 16, 2007 If you can not locate one 8" then combine 2 pieces of 6" into one piece of a larger diameter. Your a blacksmith, you can do these things Quote Link to comment Share on other sites More sharing options...
bruce wilcock Posted January 16, 2007 Share Posted January 16, 2007 try google uk .stovesonline ,or spark arresters and they have a arrester that goes on a house chimny pot for thached roof houses, they are in Devon uk ,for goodness dont buy one ,thats letting the blacksmithing side down, have a good look at there picture and go for it.and olso cut the blast down. Quote Link to comment Share on other sites More sharing options...
Ten Hammers Posted January 16, 2007 Share Posted January 16, 2007 This is a pic of my airgate. Will try and type more later on subject. This controls the blast exceptionally well. Thanks for the edit button return ! Now then, the purpose of the airgate is to control the blast. I guess I really don't know what you are using for this at the current time. THe other things suggested will of course fit your situation fine. I made this airgate from a scrapped 3" cyl. Just chopsaw a slot and make a disc and hinge/handle. Also a scrapped HVAC blower. Quote Link to comment Share on other sites More sharing options...
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