Yesterday was spent drilling out over 30 holes from 0.3mm diameter (handrail stanchions) to 1.8mm (chimney, dome & safety valves). The washout covers, studs and nuts then needed to be made before the boiler fittings could be epoxied into place as their placement would involve soft soldering.
The access covers are held down by central studs and nuts which would be represented by some 0.4mm brass wire located in pre drilled holes at the crown of the firebox: three RHS, two LHS. The covers were made from 5thou brass strip tinned with 145 deg solder and folded in a zig zag to make up six layers, sweated together and then a 0.4 mm hole drilled through the lot.
This was then filed down to size around the stud fixing hole.
After separating the covers, some 0.4mm wire was then tinned, and threaded through the cover hole and pushed into the firebox. The area was gently brought up to temperature using a small gas torch with plenty of phosphoric acid flux.
The excess wire was then trimmed off and the area cleaned up. The two holes on the top of the firebox near the cab are for the whistles, which will also be made from non tarnishing metal.
On a slightly different note, I wonder how many people recognise the source of the brass for the dome & safety valve plinth?
After making the safety valves, the next job will be to glue all the fittings in place.
Tim
