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How to weld crack on water jacket of boat

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  • How to weld crack on water jacket of boat

    Q. This winter, the water jacket on a friend's inboard boat froze and cracked. The area is easily accessible and not under pressure when operating. How do I weld the crack to secure it? I will use Devcon to seal the area after welding. I was thinking of buying Miller's 120 Volt MIG because I will have to weld using a generator. Will it do the job? (Submitted by: Tommy Powers from Peoria, IL)

    A. I assume it is a cast block, not aluminum? I have had only about 50% success at welding cast iron blocks. The 120 Volt MIG may be a little small depending on the thickness of the jacket area. If you can, drill a small hole at the end of the crack to keep it from chasing. "V" out the crack area. Pre-heat the block slowly with a torch, weld the area with a .030" ER70S-6 wire and if possible, allow the block to cool very slow. Use dry sand or a thermal blanket to keep the post-heat in the block as long as possible. If the block cools too quickly, it will crack again. Remember, the 120 Volt MIG unit will pull a lot of power from your generator. Use a large gauge extention cord if you have to. A number 10 cord should do for any distance. Thanks and good luck.