I’ve found that it doesn’t take too much “abuse” whether intentional or not to ruin an aluminum mould. Brass has recently become my favorite material here at NOE. If the mould I want is in brass I’ll pick that up over the aluminum. If not I’ll take the aluminum however.
I’m pretty much the opposite, brass starts feeling too heavy for me in 4-5 cavity configs when doing long casting sessions–though the NOE mold guides tend to make that a little better. I will take aluminum over brass most of the time. Brass does retain heat better though.
I’ve found that it doesn’t take too much “abuse” whether intentional or not to ruin an aluminum mould. Brass has recently become my favorite material here at NOE. If the mould I want is in brass I’ll pick that up over the aluminum. If not I’ll take the aluminum however.
A good casting regime and aluminium moulds will last and last with no discernable wear although they do tend to look dull over time.
I have NEI moulds from Walt’s day and LBT moulds from when Veral was young(er), they have cast thousands and thousands of bullets and the ones they drop today are as good as the first ones.
I like using brass moulds too but the weight is a real downside so aluminium all the way for me when it comes to bread and butter casting.
I forgot to add to my post that the NOE adapter for my Lee Pro 4-20 makes it several orders of magnitude easier to manage the weight of brass moulds, as cornmastah pointed out in his post.