Need a crucible?Go to Mifco.They have the best prices I have seen.I ordered 2/#16 silicon carbide crucibles for $78 each.Be prepared to wait at least 3 weeks for delivery.Salesman told me they go out as fast as they receive them.With those prices I can understand why.Also they are having problems with the web site.Better to look up what you need and give them a call.
I bought a Johnson model 900 crucible furnace recently.It is ready to go.Problem is that I don't have an insruction manual.The guy that owned it before me said that he singed his eyebrows when he tried to light it.Didn't ask any questions as to the proceedure he used.The following is the proceedure I plan to use.Any suggestions are welcome.
1.Place 2 layers of cardboard on the bottom of the furnace even though I will be using a steel crucible.My reasoning is that the burning cardboard should sustain a flame until the furnace is hot enough to sustain the flame.
2.place crucible in the center of the furnace and close the lid.
3.turn on the blower at minimum speed.
4.hold the ignition switch in while slowly opening the gas valve.
5.when it lights...release ignition switch.If it doesn't stay lit,shut off the gas and wait a few minutes for the blower to purge the furnace.Start over again.
This furnace has a momentary contact,pushbutton switch for the ignitor.Should I replace it with a toggle switch?I am not afraid of this furnace.Just want to be safe and make sure I touch all the bases.