had this happen to me this morning http://pastebin.com/nWavHQCc and was ablt to fix it in the ex astris config for now b setting it as follows B:"Tsteelworks melting allowed"=false
I'm still new to all of this so i am not entirely sure what that does or does not allow but figured a heads up would be helpful.

Yeah I reworked the lib to prepare the modtweaker support. I'll write a decent API that will prevent this from happening again in the future though (but in the meantime, Ex Astris needs to update its TSteelwork references)

Speaking of this, I've been using your shiny new API, but have gotten nothing but crashes.
Log: http://pastebin.com/pfGex3ni

I've tried doing this a number of ways, using ISmeltingRegistry.INSTANCE as well as a getInstance, both ot the same effect.
Code here: https://github.com/MikeLydeamore/Ex-Astris/blob/master/src/main/java/ExAstris/Bridge/TSteelworks.java
Wondering if you can shine some light in on what I'm doing wrong?

One of the itemstacks you're passing has a null item (probably one of the GameRegistry.findItem queries returns null)

As a result, the registry implementation which uses a hashmap fails to get the hash of the item as it is null
https://github.com/Ephys/CookieCore/blob/1.7/src/main/java/nf/fr/ephys/cookiecore/util/HashedItemStack.java#L22