Furnace Failure again, What a day

The plan was to pour new pulleys for the master mill.  Put the cruciable in the furnace.   Started to ram up the mold then realized the flask was to shallow to do it as I wanted.  So I made a flask extension.











Then I noticed the furnace/oven was not heating.   The coil repair, weld had burned away.  It was not just the weld point but the most of the exposed wire around the weld. Hmm 



I pulled the heating elements, ceramic plates.  This time I am trying a small screw to hold the wires together.




About now I noticed one of my DIY bricks had disintegrated!  It  came out whole but was clearly comprimised.  It did not take much to crumble it.

Needless to say this was disapointing. An OH SHIT moment even!   But I realized that the brick that died was an early brick, one without lime put it as a test.  Sheesh.

This brick was a bit short and I had filled in the area above it with the mix including lime but not perlite.  It looks very sound.  In fact so much so that I am starting to think that the perlite is a bad deal.  Yeah I know it insulates.   But maybe on an electric over where you need groves for the coils it should be emitted from that layer of refractory.



I recently learned that adding larger particles to a mix reduces its fluidity.  So you need a higher ratio of cement because you need to coat these, larger particles.  So I am wondering if maybe I should up the cement ratio in my mix.  Well thats what experimenting is all about.

The UPS man delived a tub of Rutland 601.  It only needs one day to air dry.  So I maybe using that.