I have 3 different soldering irons and the tips of all 3 are slowly wearing away (some very quickly). I have a very large tip, round and angled that is heated by a butane pen torch (Benzomatic) and the tip has a hole from the flat angled surface back to the flame about 2-3mm diameter! It was solid when I got it and I haven't don't that much soldering with it. I'm using Benzomatic 60/40 solder and benzmomatic flux. Is this normal or is it maybe something I am doing?

 

They will do that. The slowest that I have had to dissolve away were the iron plated HAKKO tips.

 

All copper tips dissolve. The only dependable tips are coated, and I think it's iron. Yea, Ironclad is the advertised name.