Cast Iorn Keel top flange cracked ! how to Fix

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seumask

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We have a lifting keel that had a accident earlier today when the keel was accidently dropped down the flange at the top which has two botls thorugh it to lock it down caracked and snaped off part of the flange across where the bolts go through. Do any of the forumites have any suggestions as to how to reinstate the flange so as to allow the keel to continue to be bolted down.
Is it possible to weld cast iorn or would we be better looking at some other form of structural repair
 
I stand to be corrected but from experience of having an engine block welded, fixing cast iron is a pretty specialist job.
Basically the whole "piece" needs to be heated to prevent weld hot-spots cracking the metal and/or acting as a heat sink. Gas fusion welding is the most successful method of dealing with cast iron lumps... but I doubt very much if its something that can be done in situ.
Arc welding is not advised as the weld will alter the characteristic of the cast metal, making it brittle and further repair impossible. I did hear of a method of locking splits in cast by tapping out the cast for special dies... an internet search might turn something up.
Best of luck.
 
I had a cast iron table that had a piece broken off many years ago. The solution was to have both parts placed in a furnace, and brought up to dull red heat then parts were welded. The welded assembly was then placed back in the furnace and allowed to return to ambient temperature slowly. 38 years later table still in use, prefectly ok.
 
I'm hoping to come up with a method that does not involve lots of heat that I might be able to do in situ. Current thoughts are around making a stainless steel plate to go over the crack, but then how do you attach to plate to the cast iron, bolts, epoxy both or something else.
It is possible to get the keel out however that is not easy as its 700kg that comes out up thorugh the cabin roof! Ie a major job! I will try and post a picture in the next few days.
 
Cast Iron cannot be welded efficiently. Can't visualise your problem but I suggest you talk to a machine shop about making a mild steel section to replace the busted bit then machine the keel and bolt the new bit in. Sounds a bit expensive I am afraid but welding won't work!
 
I have known of a cast iron keel that was cracked, they 'stitched' it back together in situ. Good job but not cheap as its very specialist. It's a established technique for repairing engine blocks etc which may be too big to move such as on commercial vessels.

Good luck!
 
Re: Cast Iron Keel top flange cracked ! how to Fix

Cast-iron "welding" is something of a misnomer. The process that is often used is really brazing, with a bronze filler-rod and a need for considerable pre-heat to avoid cracking. On such as a keel, electrolytic corrosion could be a serious problem.
 
Cast-iron "welding" is something of a misnomer. The process that is often used is really brazing, with a bronze filler-rod and a need for considerable pre-heat to avoid cracking. On such as a keel, electrolytic corrosion could be a serious problem.
 
Re: Cast Iron Keel top flange cracked ! how to Fix

I agree. In fact most cast materials are difficult if not impossible to weld. Cast iron can be "brazed" with a welding torch it the joint is not going to be subjected to stress but mechanical joining, drill tap and bolt, is the only solution to a problem like this normally. You could try http://www.slinden.co.uk/ Who can fusion weld some items and also have the licence to stitch a crack using "metalock" but I can't comment further without seeing it. Suggest you talk to them direct.
 
Re: Cast Iron Keel top flange cracked ! how to Fix

I have arc welded cast iron using nickel rods from Oerlikon. The rods were quite expensive. The 'cold welding' technique is described in detail on the Oerlikon site.

The repairs I carried out were satisfactory but I never had great confidence in the finished job although one on a large pillar drill which I did 35 years ago is still ok today. Perhaps my lack of confidence is misplaced and has more to do with the brittle nature of cast iron. The detailed descriptive pdf on the Oerlikon site is in Turkish unfortunately, but I bought the rods in this country so there may still be an agent.

As the part in question involves a mechanical fixing perhaps a mechanical repair would be better.

Air Liquide distribute them now website here
 
Re: Cast Iron Keel top flange cracked ! how to Fix

If you can tollerate a plate bolted to the side of the keel it should not be too difficult to drill and tap the cast iron to bolt a plate over the crack. Just buy both normal tap and plug tap for the bottom of the hole.

It must have been some drop accident to dis member the top flange.

My drop keel has a square box shape at the top which drops into a square box shaped c/b case with foil shaped hole at the bottom. If it is dropped the water in the c/b case makes a hydraulic damper with the keel top section so slowing down the crash. (and water pumped into the cabin) I still have visions of if dropping right through the hull sometimes and it only weighs 100kg.

Anyway that won't help you. Yes photos if you can do it will help.
good luck olewill
 
If you Google for <"cast iron" + repair> you will find firms who claim to be able to weld cast iron. I cannot believe that it will be possible in situ however.

You will also come across Metalock. That's a name I can remember from way back as doing some major casting repairs where I worked but whether they will do work for a private individual may be another matter.

http://www.metalock.co.uk/castingrepairs.asp

I think something like this is the only chance of repairing the casting in situ other than bolting something on if that is even feasible.
 
Re: Cast Iron Keel top flange cracked ! how to Fix

Thats what I meant by "brazing" using a welding torch. As others have said it's not really welding and I would not rely on it for a joint my life depended on.
 
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