Boiler joint leaks

[Amkibunja]

I am installing a very old vertical wood fired steam boiler, probably a 1940s/50s Cochran. It is of riveted construction.
In the process of carrying out a cold pressure test some of the riveted plate joints have been found to be leaking (at abt 5 bar pressure). Weld repair is not an option.
Any suggestions on how the leaks can be stemmed?
Thanks

Amkibunja

 

[chicopee]

Are the rivets deteriorating or cracked? was the pressure test water too cold to do a hydro? is there a crack in the ligaments between rivets? are the rivet holes cracked? During fabrication of riveted boilers and tanks, caulking the riveted edges, and I am not talking about joint compound, was a method to make liquid tight joint. The method is to cold work the steel whereby the riveted joint edge is forced against the parent metal. I doubt that you'll find anyone left to do such work. You may have to develop you own skill. Check the internet and libraries with older books on boilers on how it was done. You'll need muscle power, a heavy duty hammer and some form of a chisel to caulk.

 

[Amkibunja]

Chicopee,
The rivets are rusty and flaking, as is the rest of the boiler, though there are no visible cracks or extreme deterioration. The boiler is located in a cold highland area (by tropical standards) so water room temperature may hover around 10 deg C.
Will attempt to caulk the joints. Hope it doesn't increase the stress on them.
Thanks for the info

 

[chicopee]

Before you do anything and waste time you should clean up the rivets by sandblasting to identify the cause of the leak properly and do a dye penetrant test to identify possible cracks.

 

[berkshire]

Amkibunja
If the leak is on the edge of the plate. then you can cold stake the edge of the flange. Chicopee touched on this. The method is to take a rounded edge chisel and drive it parallel to the plate into the edge of the overlapping plate about 1/3rd of the thickness up. The idea is to make a fish tailed appearance to the edge of the plate and force this material tight to the underlying plate. \--------
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Before you do this you should sand blast with a fine grit to at least grey metal state.
This way you will uncover any rust pockets that will stop your caulking operation, before you spend time trying to do it.
B.E.

You are judged not by what you know, but by what you can do.

 

[berkshire]

Well that did not work.
Looks like I will have to do a sketch.
B.E.

You are judged not by what you know, but by what you can do.

 

[berkshire]

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edge like this.
B.E.

You are judged not by what you know, but by what you can do.