My shift to pre-heating every mold... good for defects but eats into the day.

I used to skip pre-heating molds to save time on small jobs. Then I started doing it for every pour after a batch of cracked castings. Now, my defect rate dropped by half... but the extra 20 minutes per mold adds up. Some guys in the shop say the time spent isn't worth it for simple shapes. Others argue that consistent pre-heating saves money on reworks. What's your take? Do you pre-heat every time or only for complex parts?

3 comments

3 Comments

terryg472mo ago

My old foreman in Dayton always drilled pre-heating into us, but I blew it off for years. I figured it was just extra steps for no real gain, especially on simple parts. Then I had a run of valve bodies come out with cold shuts that cost me a whole afternoon to fix. Now I pre-heat every mold, no exceptions. That twenty minutes up front saves hours of grief later. The guys who skip it are playing with fire, lol. Once you see the defect rate drop, you won't go back.

blair_webb2mo ago

Reading @terryg47's story hit home. I always saw pre-heating as a waste until a batch of housings came out with cracks. Those reworks took a full day, and now I never skip it. Doesn't that extra time up front seem trivial compared to fixing mistakes?

daniel_green422mo ago

Pre-heating might eat into your day, but that drop in defects is no joke. I've seen reworks from skipped pre-heats end up taking way more time than the extra twenty minutes. Sticking with it for all pours keeps things consistent and saves headaches later.