repairing a crack in cast iron boiler

Steve Kownacki

Our church has a hot water boiler installed in 1997 that has a 2" long hairline crack in the 2nd stack. We're waiting for a price on replacing that piece, but was wondering about repairing it. One guy put some kind of sealer in the system, which worked, but is concerned about the crack getting longer. He knows that in truck engine blocks, they usually drill from one end and put in consecutive tapered pins. Is this something that can be done in place or is there too much risk of filings getting into the system and hosing up a circulator? Is there a "simple" method of repairing this? Thanks for your help, Seve

Rich L.

JB

For a temporary repair you could try JB Weld. I've used it with good results in the past. Particulary if you're just trying to buy some time until a new section arrives. For a more permanent repair you could have the crack welded. Caution here. This is a pressure vessel in a public building and requires a properly certified welder whith an "H" stamp to weld on it. (I'm pretty sure that's the required stamp) Cast iron can be successfully welded with nickel welding rod. The easiest place to find a welder with the right credentials would be a union mechanical contractor, although there are most likley non-union shops out there with properly certified welders as well.

Good luck, Rich L

Big Ed_4

Silver Rod

We use to drill a hole in both ends of the crack and braze with 5% silver rod in comerical applactions. In public systems I don't think the insurance company will allow a repair. Better off installing a high end boiler with the high cost of fuel.

Tom Manton

A good welder

using a nickle alloy rod can weld almost any cast iron. Grind the crack to a V, preheat to 450F and burn a rod in.

Nickle alloy rod, about $10 each, $80 a pound, YIKES

Or just replace

Couderay

A good welder??

Just wondering, if you meant man, or machine? ;-)

Tom Manton

Man

A good man can overcome a bad machine.