< Boiler Completion >
The leak points were repaired one by one with Comsol. The propane gas torch is enough for the operations even for the inner firebox.
Without pickling, I need another method to clean the material surface before soft soldering. I prepared a stainless steel wire brush pen for small brass modeling. It is useful to clean local points of the copper surface.
After the repairs, I executed the fifteenth pressure test. Finally it became easy to increase the pressure up to 1 MPa, however the leaks didn't disappear perfectly. Same as always, there are several leak points around the inner and outer fireboxes.
After that I repeated a number of repairs and tests and finally the leaks from inner forebox stopped at the eighteenth pressure test.
At the nineteenth test, the water pressure is increased to 1.25 MPa. I found two leak points at the outer left sidestays and there is no other leaks.
I tried to seal the leaks with a center punch. I punched on several points around each sidestay, then the leaks stopped. When punching, you should release pressure. This hand pump set contains pressure release valve and is able to alternate pressurizing and releasing quickly.
The final pressure test was executed. The working pressure of the boiler will be 0.5 MPa. According to ASME boiler code, the test pressure shall be 1.22 MPa. Therefore I maintained 1.22 MPa for fifteen minutes and confirmed there is no leak point. At last the boiler passed the pressure test.
The completed boiler looks so bad because I decided not to pickle the boiler again.
In order to take a little better pictures, I prepared wire scrubbers coated with soap and polished the boiler surface with water.
The completed and cleaned boiler. The lead color indicates soft soldering points.
The various parts of the boiler deformed because of a number of repairs. Especially the bushes on the backhead are far from parallel. For the water pressure gauge, I will adjust the shape of the glass pipe holder in order to keep the pipe straight.
I uploaded some movies on Youtube introducing the soldering operations.