propane and oxygen ratio

[agata]

I’m looking for correct ratio between propane and oxygen for casting semiprecious and nonprecious metals

 

[tuyere]

We always used a neutral or gently-reducing flame for melting metal for jewellery casting, sometimes a flux depending on how aggressively oxides formed. It'll vary from alloy to alloy, there should be a materials sheet from the manufacturer on how to work with it.

 

[TheLabGuy]

I use 4:1 ratio....My readings are 24 p.si. for oxygen, 6 p.s.i. for propane. Been using those for high, noble, and base for a couple decades. I'll adjust flame to the metal i'm casting...obviously, more oxygen flame for base metal compared to high noble.

 

[Car 54]

I've always used a multi-orifice casting tip for NP and HN, which helps.

 

[Affinity]

I think I read here a long time ago, or maybe in a casting manual, light your propane first and adjust your flame to 16", then slowly add in the oxygen until your flame is 1/4-3/4" , depending on alloy. The gauges on the bottle only work if youre wide open on the torch, I adjust my flame manually on the torch. Youre looking for blue cones about 1/4", its always better to have more gas unless your casting gold.

 

[bullit]

I use a Harris torch, multi-orifice top, 35 psi oxy., 7 psi propane

 

[B@IDL]

3:1 - 4:1 depends on the metal you try to heat. Use a "step down" regulator setup to control the pressure better.
Some of the non precious need high heat , sometimes difficult to produce with small nozzle or easy to overheat if its create pin point .
I'm using a Victor Multiflame VIC6-MFA-1 torch mostly for Cr/Co - Wironium casting. Nice long nozzle to stay away from the heat and comfortable to do many casts.
Also used to cast anything C&B and Full Gold. Use Flux and clean crucibles.

 

[ztech]

All of the Jensen High Noble alloys are 20psi O2 and 10 psi propane. Light with gas trim with O2