Sunday 9 June 2013

Concrete Evidence

SR timber and concrete, side by side
My 3D-printed SR concrete sleepers for Chelfham, after several attempts, gauge correctly. The tirefond holes are barely more than dimples and need drilling to take the lace pins. I blackened the pins first, but most of the blackening doesn't last the process. The process, by the way, involved rather more pulling from underneath than pushing from above: that won't be practical on the viaduct!