# how to repair cracked antique cast iron fireplace surround?



## antiquestuff (Nov 5, 2004)

I have an old cast iron fireplace insert/surround, not installed but just storing it for now. Quite large. It is similar to this one, but not as fancy (more of an arts and crafts style): http://cgi.ebay.com/ANTIQUE-VICTORI...363822999QQcategoryZ63518QQrdZ1QQcmdZViewItem 


Mine is complete though with a "grate" or fender on the bottom of the opening that is maybe 6 or 7 inches tall, and a cover for the rest of the opening, to cover it when not being used. However, the tall,narrow part on the right side of the "opening" is cracked right between the pilaster/column and the top portion. It is a tight crack and the pieces when put tightly together look fine, but, the other side of the top header piece is still attached and I'm afraid that end will break too if the cracked end isn't repaired (cause it's loose and flops around if it's touched or moved. Right now it's in a closet leaning against the wall). 

Obviously, I'm not using this thing yet, but hope too in the future, and I want to repair the crack. How should I repair the crack, to hold it together tight, permanently? Obviously, it needs to be fairly heat resistant because someday I hope to use this thing. Any ideas? It's all cast iron BTW.


----------



## moopups (May 12, 2002)

Cast iron can be welded by a very exsperienced welder, it requires a very specific type of welding rod and method. Take it to a pro for best results.


----------



## antiquestuff (Nov 5, 2004)

Thanks. I'll have to find a good welder. Didn't realize it could be welded.


----------



## Explorer (Dec 2, 2003)

Bigger cracks in cast iron are best welded. If it is a very small, fine, crack an epoxy like JB weld should work. I have used JB Weld to repair many metal items and it really does hold up. 

If the welder dosen't know what they are doing - it is ruined.


----------



## Cosmic (Jan 19, 2005)

Lot will depend on the thickness of the cast, if it good quality metal. Only gray cast usually will weld. There are several tricks to welding cast iron.

First, you cut a groove into the crack. One big problem area is near the surface. When cast iron is poured, much of the impurties migrate out toward the surfaces of the mold. Those can make welding very difficult, especially in shallow areas near the surface. So therefore, thin sections of cast iron are difficult to weld. Sometimes difficult to get the weld on the surface to fill in nicely in the surrounding areas. That surface zone can be tricky. Anything say thinner than 1/4" thickness can be very, very tricky and usually does not produce a nice looking result, even if you manage to stick it back together.

The second requirement is to preheat the work well before attempting the weld. Most times you post heat too. I used to use an old wood stove that had a good flat top. Get a roaring fire going and lay the cast iron to be welded on the stove for a period to preheat it. Also used a propane torch to further heat the weld area. Weld on top of the stove, all that heat is good. Then let it stay on the stove for a long gradual cool down after welding.

The rod used is not that important. Those made for welding cast work good. I also had good luck using stainless steel rods.

Most important everything must be clean, no rust, the area prepped to get into good solid metal to start the weld. I used to start with a bit higher heat setting than I thought necessary and adjust down. If it don't look good on the first small bead, STOP and figure out why. It ain't going to get better with the wrong procedures, materials, etc.


----------



## ace admirer (Oct 5, 2005)

hello, is the cast iron fire/heat damaged in any way at the crack...crazing or little allegator looking scales? if not, the chance of repair is good. the welding rod used is a nickel rod and usually cost a few bucks each..it has almost no penetration so the crack will have to be ground out to make room /create surface area for the rod to fuse to. the resulting repair could be ground back to near orginal shape.. or

if the surround does not get too hot the crack could be brazed. the crack surfaces have to be ground to produce a clean shinney surface, but no grooving is necessary as in the nickel rod repair. it would probbly be best if the part was actually broken into two parts. that way each surface could be cleaned up with a grinder with out haveing to grind a wide groove. 

as others have already indicted...the part needs to be evaluated by an expericened job shop welder.(guys that see different jobs on a daily basis). depending on the curviture of the cast part, it could be a fairly easy repair (for a welder) or a nearly impossable repair. 

it must be a very nice part...have not seen anything like it around here. good luck.


----------



## norris (Dec 25, 2004)

Welding cast iron is a delicate science and the repair will not stand up to repeated heating at that temp range. Also, JB weld burns at 400 degrees. I would get a piece of 1/8 by 3 flat steel and patch the crack by bolting the steel to it...or get a good woodstove. Sounds like you have a Franklin.


----------



## raymilosh (Jan 12, 2005)

i have had good luck welding cast iron woodstoves before. Even parts that get heated, like grates. I have been surprised to have the repars last. I was basically experimenting to see if it would work. 
I use cosmic's method of heating before and after, but i use an oxy acetylene torch and heat both pieces to red, then orange and halfway to yellow, but not hot enough that it begins to "sparkle". I weld it while it is that hot. 

Most welders i have talked to tell me that cast iron cannot be welded. So, when you are out looking for someone to weld it for you, expect a few to try to convince you that it can't be done. Just keep asking until you find someone who says, "Sure, no problem."

By the way, the fireplace cracked because it was OVER fired....someone got it really really hot. It will crack again if it is over fired again.


----------



## Ross (May 9, 2002)

I had a cast iron stove part welded and the method was similar to Cosmic's description except the welder used a MIG. Worked well but I wouldn't attempt it myself


----------



## moopups (May 12, 2002)

Welding cast iron does use different methods. The one I am familiar with involves first placing your hand on the metal next to the crack, gague the distance of the width of your hand, now place your hand at the edge of the distance, weld with the other hand. As soon as you feel the heat of the weld, stop right there. Let the cast iron cool for as long as is necessary so that no heat is felt, then you can weld again. Nickle or stainless steel rods both work, for arc welding.


----------



## Hip_Shot_Hanna (Apr 2, 2005)

Stainless rods are the best for cast , its what i have used for repairing Cylinder blocks


----------

