So, it's hard to describe, but here's the flaw that I've found:

This is because you've registered Electrotine Alloy as "ingotElectrotine" and Electrotine Dust "dustElectrotine". Thermal Expansion automatically puts 2 and 2 together and assumes the dust is a pulverized version of the ingot. My only thought / suggestion is changing "dustElectrotine" to "powderElectrotine" or just plain "electrotine".

But then it would go against the naming conventions. The solution here is to have Thermal Expansion include a way to blacklist certain dusts in their API.

Suggestion: change the name of 'Electrotine Ingot' to something like 'Blue Alloy Ingot' (ingotBlueAlloy) or 'Electrotine Alloy Ingot' (ingotElectrotineAlloy), since currently the dust and the ingot are made of different materials, but have the same name.

Electrotine Alloy Ingot.

Will do. It actually is an alloy anyway, you mix it with iron...

Fixed via 57cded5.