Steam Department

A few of us have managed a couple of mid-week work sessions over the Christmas period.  The significant visible progress is that Eric and Chris did a great job on cleaning out the interior of the boiler on 1630.  After all the cutting of tubes there was a mass of debris in the boiler that they spent most of Monday clearing with brushes, rods, magnets and vacuum.  Thanks to their efforts we now have a good basis for preparing the surfaces for inspection.

A step that we need to carry out soon is the sand blasting of the firebox tube sheet.  We have the sand blast equipment, breathing helmet and supply hoses BUT - no really suitable breathable air pump.  If anyone has access to a suitable pump - (oil-less, about 10 c.f.m. at 5 p.s.i.) please let me know. Otherwise we are facing a cost of about $1000 for such a pump.

I had the chance to photograph the firebox with the defective corner cut out:

The defective corner is now out

.............. and the piece removed:

Long hidden view of the defect

Interesting that it is very much in line with the problem suspected by the specialist who attempted the temporary repair in May.  This was that, when a replacement tube sheet was fitted (believe in the late 1930's), it may have been fractionally narrow and pulled into place by the rivets causing stress cracks in the corner.  Looking now at what is the inside (water side) of the corner you can see the welded joint between the "new" tube sheet (on the right) and the original firebox.  This runs thru the last rivet hole on the left in the top row.  Sure enough you can see that the tube sheet is fractionally set back from the original firebox side.  The crack that resulted can be seen running from the second rivet in the top row.  (They look a lot worse now as a good deal of metal was ground away from the other side of the plate when removing the rivets).  These cracks would have formed over many years as water worked on the weaknesses caused by the stress in the corner of the new tube plate.

The other major work in these sessions was unplanned!.  Initial testing of the swager disclosed several problems.  The large dies that actually compress the pipe proved to be jammed.  Several of us spent a day removing, carefully cleaning and polishing the guides and refitting these.  Sounds easy but each weighs about 100lbs and they are linked by 4 inch long 1 1/2 inch steel guide rods that must be a tight fit - but not jammed!.  Good thing there were not too many around to hear the language on the occasions when we put them together, found they still jammed, and had to get them apart again!.  Still, they are now back in place ......... and it is clear that there are also issues with the air control valve.  So that is the next step.

Nigel Bennett