Wolf's Den Armoury Posted November 8, 2009 Share Posted November 8, 2009 (edited) everal years ago, I received my forge (as well as the rest of my smithing equipment) as payment for some historical reenactment maille I had made for a client. It sat pretty much idle for probably 5 years until a little over a month ago when I had a sudden *need* to fire her up. (don't laugh...you know you've been there) Anyway, I noticed a fairly substantial crank on one side of the firepot A buddy came over with his arc welder and "stitched" up the crack on the inside of the firepot, so that seems to be fixed for now, but what's a bit of a concern to me right now is the rather decent sized hole that seems to have developed around the tuyere... It's also migrated to a spot in the firepot where open air is visible (it's large enough that some good sized chunks of nugget coal have fallen through! So I guess my question is..... 1) what would be the best way to repair this well-used old soldier? I'm fairly certain that it's cast iron. 2) would it really be worth it? Should I just start over and make a new one? It actually feels bad to think I may have to actually retire this old forge. (my wife keeps threatening to turn her into a planter) Edited November 8, 2009 by Wolf's Den Armoury Quote Link to comment Share on other sites More sharing options...
Thomas Dean Posted November 8, 2009 Share Posted November 8, 2009 It is salvagable. Cut a piece of 1/8" just so it fits the entire bottom drill holes to match the fire pot. The "weld" your friend made on the sides will most likely crack. The best way is to put a strap across the crack with a piece of 1/8" flat, drill holes about 1in from ends and holes to match on the sides of the forge pan. This will keep the pan together along with the plate in the bottom and you can still use it as a forge. Just a few bolts, some 1/8" plate, drill moter, drill bit, and about 30 minutes. I used 1/4" bolts drill your holes 5/16" to allow for the expantion. You will need to bend the strap for the side repair to fit the contour of the forge. Good luck. Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted November 8, 2009 Share Posted November 8, 2009 A couple of suggestions to keep it running. Make a steel liner to cover the holes. All cracks should be stop drilled to keep them from spreading. If you have the pieces they can be reattached. If it welds easy enough (some cast isn't readily welded) I would do that , otherwise brazing will do it. When I weld cast iron I grind weld preps, preheat the part around too hot to touch , then start welding. Short 1"-2" stringer beads are used with a heavy application of a needle scaler as they cool. Stagger the beads to help control warping. The needle scaler spreads the weld as it cools which keeps it from pulling away from the cast iron. After the welding is done a post heating is done to bring the area up to a uniform temp then it is put into an insulating media. I use the gray ashes out of a wood stove. I have mine in a cut down 55 gal drum. This allows the part to cool down very slowly which reduces the chances of cracking. I have had poor luck using the E99 electrodes, and now use higher grade rods for my repairs. More expensive @ $50+ a pound, but they lay down soooo much nicer. You can also line the forge with a refractory cement / clay. May even be able to use a woodfire clay from a pottery supply house. I have some woodfire clay that is good to cone 14 2525 F / 1390 C. It all depends on your intentions. You can save the forge , or let it become a planter---Gee honey, I guess I will have to get a new forge now. Or, you can take it on as a challenge to see if you can keep it running for the next 100 years. Whatever you decide to do you will have people that agree with you. Quote Link to comment Share on other sites More sharing options...
Thomas Dean Posted November 9, 2009 Share Posted November 9, 2009 The welding of cast is 'iffy' at best and BIGGUNDOCTOR has a good repair outline but in this case welding a forge pan in this condition is virtually impossible....look at the thin cross sections in the 2nd and 3rd pictures. If is was new cast, never been in a hot fire...repeatedly... then a weld repair would work. Ths cast is too far gone to spend the time and money for any type of welding, arc or brazing. You can see in the 1st picture where a 'weld' repair has been attempted in the past, the same results will come with the next 'weld' repair. Also you can see in the 4th picture that someone has used a piece of plate to cover the bottom of the forge and it appears to have been 'welded' to the pan. Quote Link to comment Share on other sites More sharing options...
Wolf's Den Armoury Posted November 9, 2009 Author Share Posted November 9, 2009 When I got the forge, it already had a small piece of 1/8" flat stock bolted to the pan across the crack (which has widened, but not migrated). All the welding was done with my buddy's stick welder, including the portion with the small plate. The tuyere is bolted to the plate (got it that way) and every time I fired her up, the plate would shift and the tuyere would move *with it* whenever I moved coal around. Maybe it's just time to put the old girl to rest and build a new one. I can re-use the tuyere for the next forge, so that's an expense I won't need to worry about. Hell, for the matter, I might be able to forge the pieces for the new forge with the old one....kind of an asexual reproduction thing.... Thanks for the advice guys. David Quote Link to comment Share on other sites More sharing options...
Rob Browne Posted November 9, 2009 Share Posted November 9, 2009 No need to get rid of the old girl. As already said a plate across the bottom of the forge bolted in, some straps or a plate across the crack, also bolted, connect the tuyere to the new plate and you have a functional forge. Much easier than starting from the beginning. Quote Link to comment Share on other sites More sharing options...
David Einhorn Posted November 9, 2009 Share Posted November 9, 2009 It depends on your finances and preferences. You could patch it up like people have already said. However, what you have is a "rivet forge" and it is limited in what it can do, and limited in how much iron it can heat at one time. If you intend to get more intensely into blacksmithing, then I would suggest investing in building at least a 2' by 2' forge with a well-made commercial cast firepot. Using a rivet-forge is like painting a house with an eyebrow makeup brush. It can be done, and you can have fun doing it, but it has its limitations. :D Quote Link to comment Share on other sites More sharing options...
Wolf's Den Armoury Posted November 9, 2009 Author Share Posted November 9, 2009 (edited) No need to get rid of the old girl. As already said a plate across the bottom of the forge bolted in, some straps or a plate across the crack, also bolted, connect the tuyere to the new plate and you have a functional forge. Much easier than starting from the beginning. OK, then...I have a stupid question related to the plate...would the lid off a 55 gallon oil drum work? or would it be too thin for this use? I only ask because it seems to be approximately the same size (or I could trim it down a little bit). To drill the bolt holes in the original pan...I have a DeWalt 18v cordless drill...would this have enough cojones to do the job? Any particular size/type bit I should use? (If the drum lid is sufficient, I can just punch the proper size holes.) How many holes should I drill around the outside of the pan? Would eight (8) be sufficient? If it's not necessary, I'd really rather not get rid of her, so going to try and repair her as best I can. By the way, thanks UnicornForge. I had no idea what kind of forge I have. For now, I'm just going to be doing little doo-dads and decorative stuff while I learn how to do this wonderful art. I like the idea of having a larger forge like you describe, but being honest with myself, I'm not quite ready for that yet, nor am I quite at the level of expertise that I would feel comfortable having a forge that size. Thanks for the suggestion anyway. David Edited November 9, 2009 by Wolf's Den Armoury forgot to add a question...cuz I'm a pain in the butt :D Quote Link to comment Share on other sites More sharing options...
Thomas Dean Posted November 9, 2009 Share Posted November 9, 2009 The barrel lid is too thin. You will need at least 1/8" plate but you can use heavier...it just may cost a little more and add to the weight. Yes, your drill is big enough. I have a portable forge for demos...see my gallery for pics... and I can forge weld using it. But it has some slight modifications to the origanal. I poured an industrial refrac. and made a "firepot" with it. Have forge welded 1/2" with no problem. My primary forge in the shop is a large Canady Otto that is 33"x46" and has a 10"rd firepot made from 3/8" Inconel 600 plate. Will not burn up, no scale, made for extreme heat. Quote Link to comment Share on other sites More sharing options...
Dave Leppo Posted November 11, 2009 Share Posted November 11, 2009 My humble opinion is that these portable forges with the wide shallow pan and no actual firepot can be greatly improved by adding a actual firepot, 4 Quote Link to comment Share on other sites More sharing options...
Iron Bear Posted November 12, 2009 Share Posted November 12, 2009 My only forge right now is a portable one, and a pretty small one at that. One thing I will say is that my forge construction might be clumsy and heavy for its size but it's pretty functional. What I did was start with a small metal cart about 4 feet long that's made from 1" tube steel and was originally designed as an engine cart for auto shops. On top of that I have 1/8" plate running 2 feet out, with a 2" hole in the middle. On top of the plate I have brick stacked on edge covering the plate entirely and sealed with high-temp cement. In the middle of the brick with the bottom just coming out the 2" hole in the plate is a brake disc scrapped from a larger tow truck type wheel. The disc is cast iron I think and withstands the heat very well, and is at least 1" thick at it's thinnest point. It has a 2" steel pipe flange bolted to the bottom for the tuyere. It is about 12" diameter and sits about 3 1/2" deep. Only problem with the cart is it's kind of heavy, and if it gets bumped around a whole lot on the road the cement cracks. Other than that it's fairly solid, and I love having extra 1" bar sticking out on the sides of the cart because I can hang tool holders and all sorts of stuff there and have it with me when I wheel it around. The cart also has locking casters just to make it a little bit more stable if it's sitting on uneven ground. Anyways, I don't know if that'll help ya - I know how lot's of people like to stay away from the whole brake part thing, but hey it was free. In fact the only things I had to pay for were the pipes for the tuyere and ash trap, the high-temp cement, and the straps and rivets to hold the plate to the cart. Everything else was junk I picked up or acquired from a scrapyard. Good luck on your project! Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted November 12, 2009 Share Posted November 12, 2009 I'd stack the brick on the flat and skip the cement just put a good rim around the edge so they don't fall off. less cracking issues, less weight. Quote Link to comment Share on other sites More sharing options...
Iron Bear Posted November 13, 2009 Share Posted November 13, 2009 Good idea. Maybe I'll just turn up the edges of the extra plate I have sticking out and use that to hold the brick in place. The cement comes off on it's own sometimes anyways, so I can probably just chip the rest off. Ty for the advice! Quote Link to comment Share on other sites More sharing options...
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