Well.... not the outcome that I was hoping for today.
During the initial air test at 15 psi a couple of weeks ago it was apparent that there was a small leak where one of the fire tubes joins the end plate at the top of the boiler. I mechanically expanded the end of the tube which seemed at the time to do the trick as the boiler held 15 psi of air after that.
Today, however, under hydraulic testing to 90 psi that leak has come back to haunt me. I suppose that given this is my first effort I should be a bit pleased that there appear to be no other problems. However, this leak has to go. Further attempts to mechanically swage the tube end (without heat) have only made the leak worse, and it is now dropping from 90 to 45 psi in 30 seconds. I could fiddle about with it more but I'm afraid of stressing the end of the tube. The photos below show the problem - it's the tube at bottom right, marked in blue. You can probably see the stress marks inside the end of the tube but fortunately there doesn't seem to be any leakage on the inside, just round the outside where it joins the end plate.
My thought is to try to deal with it by caulking it with a ring of low temperature silver solder round the outside of the tube. I used medium temperature silver solder initially on that part of the boiler so my hope is that if I can do it this way I might be able to avoid disturbing other joins which seem to be ok at the moment. I'm also thinking of using my small portable oxy-mapp torch (instead of the big bad boy) to keep the heat as local as possible.
Does this seem like a reasonable plan under the circumstances? Or do any of you good people out there know of a better way for me to tackle it?
Photos:
Thanks,
gary
