Jeshua- platinum casting is done above Iron temps- about 350-900 F above. So any of the platinum casting investments will work. I have used Ransom and Randolph for all gold and silver investments I use- and have had great results.
Kerr also makes a good investment some swear by.
If you have never used jewelry grade investment- please make sure to follow the water ratios for mixing.
If you are using it for Iron, try referencing the manufacturer by email. I did several non-standard alloy melts with non-precious metals for a client and the guys at Ransom/Randolph were more than helpful. They referred me to a few papers from the Santa Fe Symposium that hit on exactly I needed.
Just my experience.
From: bs190815 <rpisquared@...
Sent: Friday, May 24, 2013 8:19 AM
Subject: [hobbicast] Re: Iron Investment
Here are several, never tried them, but they are for high temps.
--- In mailto:hobbicast%40yahoogroups.com, Jeshua Lacock <jeshua@...> wrote:
> Can anyone recommend a source for investment for iron castings?
> Jeshua Lacock
> 3DTOPO Incorporated
> Phone: 208.462.4171
[Non-text portions of this message have been removed]