youngdylan Posted July 13, 2010 Share Posted July 13, 2010 My tuppence is: 3 mechanisms of heat transfer: conduction convection radiation Conduction through air hardly applies here, air is an excellent insulator Convection (moving air) as Bob / Grant point out most of the exhaust gasses of a coal/ coke forge go up the flue, most gas forges tend to vent A LOT of VERY HOT exhaust gases into the room Radiation, The exterior walls of a hot forge radiate some heat but a **** lot is radiate when the doors are open/ ajar and you can see yellow. I've never used coal but with coke I cover the fire with black coke to keep as little of the "red stuff" radiating heat, makes a big difference Conclusion: Coal forges are much cooler than gas (both being o f the size non industrialists use) Follow Up, my workshop is 400 sq ft and I some times run my gas forge with 3 off 3/4 inch burners going. I NEED an induction heater Link to comment Share on other sites More sharing options...
Frosty Posted July 13, 2010 Share Posted July 13, 2010 Talk to Grant about an induction forge. Frosty the Lucky. Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted July 13, 2010 Share Posted July 13, 2010 Need some kind of certification to enter the UK. Well, they look like a big tower computer, maybe we could fool em? They might ask about the water connections though. Link to comment Share on other sites More sharing options...
Frosty Posted July 13, 2010 Share Posted July 13, 2010 Bummer. Then again it's probably cool enough where he lives a roaring fire might be welcome. Besides he left "Induction" off his list. Frosty the Lucky. Link to comment Share on other sites More sharing options...
youngdylan Posted July 13, 2010 Share Posted July 13, 2010 Bummer. Then again it's probably cool enough where he lives a roaring fire might be welcome. Besides he left "Induction" off his list. Frosty the Lucky. Time to get geeky: induction heating doesn't transfer energy as heat, it transfer energy via electromagnetism and induces eddy currents (big short circuits) in the bar. It is this massive local flow of current that heats the bar (not hystresis) ..... I think. Grant will be able to explain it better/ correct me. Heat only goes where it's neede with a small radiant loss... Gotta get one! Link to comment Share on other sites More sharing options...
youngdylan Posted July 13, 2010 Share Posted July 13, 2010 Need some kind of certification to enter the UK. Well, they look like a big tower computer, maybe we could fool em? They might ask about the water connections though. I'll contact you again about importing that tower computer I desperately need Grant ;) Link to comment Share on other sites More sharing options...
wampus Posted July 14, 2010 Share Posted July 14, 2010 In response to your coal shortage,I have the same problem here,I make charcoal. It doesn't burn as well as coal,but it gets the job done. Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 14, 2010 Share Posted July 14, 2010 I haven't put in the ridge cover for my metal roofed shop extension yet---I like having a 6" vent along the ridge during the NM summer and rain is not much of an issue here---we have had .6" this month though; it's the monsoon season! Link to comment Share on other sites More sharing options...
fat pete Posted July 14, 2010 Share Posted July 14, 2010 I have both...coal is cooler for the room but dirtier...propane blows that heat into tthe room..altho propane dries the air in the humidity i find it way more hotter in the room. However a btu is a btu doesnt matter what produces it its a btu. I have heard people tell me the heat doesnt stay in the metal as long as coal...cant be! NO chance. The only difference would be the scaling is more with propane than the gas...only difference. 1000 degrees is a thousand degrees no matter what makes it. The nature of a propane forge is why it makes the room hotter...it blows into the room...duh!! the coal is in a contoled pile so it may radiate a bit but it dont blow into the room... Link to comment Share on other sites More sharing options...
billp Posted July 14, 2010 Author Share Posted July 14, 2010 I have both...coal is cooler for the room but dirtier...propane blows that heat into tthe room..altho propane dries the air in the humidity i find it way more hotter in the room. However a btu is a btu doesnt matter what produces it its a btu. I have heard people tell me the heat doesnt stay in the metal as long as coal...cant be! NO chance. The only difference would be the scaling is more with propane than the gas...only difference. 1000 degrees is a thousand degrees no matter what makes it. The nature of a propane forge is why it makes the room hotter...it blows into the room...duh!! the coal is in a contoled pile so it may radiate a bit but it dont blow into the room... Will through all the hub bub and debate, the good advice and the some bad, Fat Pete you have made the most sense of them all in a way this simple Tennessee man can understand the best. Oh and I started with charcoal and did Ok with it just got to where I prefer coal. Again thanks to all who responded BillP Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted November 13, 2010 Share Posted November 13, 2010 Bill P, I know this is late to the party, an un insulated steel roof is a big problem. The sun beats doun on the roof, it heats up to a temp higher than the ambient air temp and radiates doun on you. The ice house roof mentioned helps because you get only half the heat radiated doun to you. Aluminum, even aluminum oxide reflects 98% of radiant heat. Insulate your building, an air gap of 1/4-1/2 and a foil faced rigid panel is easy to work with. If your building is typical of sheds venting between the outer skin and the insulation shouldn't be nessisary, remember most insulation is flammable so cover It with dry wall or tin. Sorry for rambling. Link to comment Share on other sites More sharing options...
ianinsa Posted November 14, 2010 Share Posted November 14, 2010 This too may be late in the day for Dylan and Grant, Commercial Import restrictions don't always aply to "presents" and "broken" goods. We occasionally send goods between our shops or projects by DHL. My partner simply sends the parcel from his home adress to my home adress with the note "last time I was at you place I saw your brocken piece of junk so please acsept this as my birthday/chrismas/eid/aniversary/etc. to you. A value is declared and insured for. Depending on the value HMC might even wave duty but are very vigilant on VAT collection. Your note could also say " I bought this but it does'nt seem to work, it's similar to the one that you were using can you fix it?" Please remember to post instructions,receipt and g/tee seperately!You keep the payment a seperate transaction- chrismas gift for Grant's wife? Dylan? On the debate of coal v. gas as previosly noted coal has a flue thet causes a draw. Thus the more efficient the flue the better the draw. The greater the draw the more air drawn through the shop(draft) and unless the shop is in a really hot and dry desert this draft will have a cooling effect on the entire shop. On insulating the roof, first ensure that you have decent ridge ventilation,the hot air rises(escaping through the ridge vents)and also creates draw(a draft) so too helping to cool the shop. Ian Link to comment Share on other sites More sharing options...
dablacksmith Posted November 14, 2010 Share Posted November 14, 2010 ok just a little info from someone who also has to deal with 100 degree weather i use coke! not much different from coal but it lasts 3 times as long for same weight and i found a supplyer that ships by the ton . its a little different burning but not near the fumes /smoke as coal .it is still hard to work thru the heat of the day tho.. ive been doing other things till the weather cools . will go fulltime now that its in the 70s .good luck and i find shade and a good fan does help but nothing will help when its in the 100+ range.. Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted November 14, 2010 Share Posted November 14, 2010 2 things Dablacksmith- how much are you paying for a ton of coke? Billp-isn't Tennessee coal country? Hard to imagine you not being able to find coal. Link to comment Share on other sites More sharing options...
Chalky Posted November 15, 2010 Share Posted November 15, 2010 billp - if it's too hot to work in the middle of the day think yourself lucky . Just have a siesta! Link to comment Share on other sites More sharing options...
dablacksmith Posted November 15, 2010 Share Posted November 15, 2010 2 things Dablacksmith- how much are you paying for a ton of coke? Billp-isn't Tennessee coal country? Hard to imagine you not being able to find coal. one ton of coke last time delevered was 600?? somwhere around that .. as it will last 2 years i dont think its too expencive ... i think it lasts 3 times longer than coal and i can go a week on a bag .. your use may vary. Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted November 16, 2010 Share Posted November 16, 2010 Thanks, I can get a ton of coal up the road in Utah for $120 a ton. I still need to swing by their place to get a sample, or see if they have an analysis of it. When I was back home in N.CA some of the guys were getting coke from the big refineries that were near us. Link to comment Share on other sites More sharing options...
pip Posted November 20, 2010 Share Posted November 20, 2010 coal is better for what i do ,but i can agree coal is hard to get. i heard that some people can forge with swamp gas it seem i little far fetched. after all it is just a Mississippi legend. Link to comment Share on other sites More sharing options...
thingmaker3 Posted November 20, 2010 Share Posted November 20, 2010 Bill P (and anyone else who needs a low-tech personal air conditioner) Take a bit of cloth and make a tube 2" dia by a yard long. (Or have someone with sewing skills do so.) Sew the tube closed about a foot from one end. Put in some "hydrophillic grains" and sew the other end closed a foot from end. Soak in cool water. The hydrophillic grains suck up the water & make a cloth-sausage looking thing. Now tie the thing around your neck like a bandanna, with the "sausage" at the back of the neck. Evaporation keeps one cool for a couple hours. My wife made me two of them, and I swap them out. She got the idea from some she bought at a local art market. Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now