How casting temp affects size

Elric

Well-Known Member
smoke the mould, etc.

I smoke 'em if I got 'em... Using kitchen matches gives a dry soot, while a butane BBQ lighter gives a sort of greasy soot.

Spray on mold prep can build up and create problems... Just my deathless wisdom.
 

Bret4207

At the casting bench in the sky. RIP Bret.
To each their own. My point was for decades you HAD TO SMOKE THE MOULD or bad things would happen. I gave up on it a couple decades back.

Spray on mould prep- an answer in search of a question. Makes a fair lube for sliding surfaces you don't mind being filthy black, like manure spreader chain.
 

358156 hp

At large, whereabouts unknown.
I only use commercial Mold-Prep for ladles and skimmers. It helps keep lead from hanging on to the tools.
 

CZ93X62

Official forum enigma
Lee aluminum moulds are the only ones I "smoke". They seem to need it. Aluminum Mtn. Molds, Accurate Molds, NEIs, and NOEs haven't required the smoke, nor have my iron/steel Lymans, RCBS, or SAECOs.

My thoughts (let's also remember that I was a social science major 40+ years ago) are that smoking a mould cavity provides an ablative coating that slows/retards heat transfer from the poured metal into the 'heat sink' that a mould block actually is. Why just the Lee blocks? Not sure, but I suspect it has something to do with the different aluminum alloys used by the mouldmakers and the quality of cavity finish that each maker gives to its end products. I'll do what I need to do in order to get good bullets from my tools, and IME Lee moulds require BY FAR the most gymnastics to get good bullets from.