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Shoutout to the old timer at the scrap yard who changed my mind about pre-heating | Foundry Workers - Discusd

Shoutout to the old timer at the scrap yard who changed my mind about pre-heating

Honestly, I was loading up a batch of aluminum scrap last week and the yard guy, Frank, saw my setup. He said, 'Kid, you're pouring cold metal into a hot crucible like you're making instant coffee.' He told me he used to lose a whole shift, about 8 hours, every time a crucible cracked from thermal shock back in the 80s. Ngl, I always thought pre-heating the charge in the oven was just extra work for no real gain. Has anyone else had a moment like that that made you change a basic habit?

3 comments

3 Comments

margaret6926mo ago

Totally get that... I had the same stubborn thought about letting my forge cool down slowly. Watched a guy at the club just shut his off and walk away for years. Then one day his brick lining just fell apart in big flakes. He said the fast cooling makes everything brittle... like glass in cold water. Made me feel a bit silly for rushing the process. Now I just let it sit overnight even though it's boring.

jaden696mo ago

Man, that's so true about the slow cool down. It's like the heat wants to leave all at once and just tears things apart from the inside. I started doing the same thing with my little hobby forge after I saw a crack form right down the seam. Now I just turn the gas off but leave the blower on low for a while to pull the hot air out gently. It adds maybe ten minutes to my clean up, but it beats re-lining the whole thing. Some of these old habits really are just cheap insurance.

emma7685mo ago

Leaving the blower on low is smart, but pulling hot air out fast can still cause a shock. The goal is to let the heat leave slowly from the inside, not force it out. A better move is to just shut everything off and close the forge door to trap the heat for a while. That gentle soak back to room temp does more for the lining than active cooling.