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Spent 3 hours chasing a sanding defect that was just some old wax from the pattern
Turned out the previous guy used a release agent I'd never seen before and it took me way too long to figure out why my finish kept fisheye-ing, anyone else run into mystery contamination on your molds?
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perry.jesse2d ago
Man I used to think it was always user error when stuff like that happened. A few years back I had a mold that kept giving me trouble and I swore it was a bad batch of resin. Turned out the pattern had been stored next to some silicone spray and it soaked in somehow. After that I started wiping everything down with acetone before I even start sanding. It's wild how just a little bit of leftover wax or release agent can mess up hours of work. Now I treat every mold like it's suspect until I prove it's clean.
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abby_fisher2d ago
Plenty of times contamination is just a convenient excuse though. If your process is solid and your workshop is clean, most molds should work fine without all that extra paranoia. Sometimes a bad pour is just a bad pour, not some deep hidden contamination mystery.
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anthony_jackson312d ago
Watched a video from a composite repair guy who said old wax contamination acts like a ghost in the mold, stays hidden for years. @abby_fisher makes a point about solid processes but even the cleanest shop can't stop what's already soaked into the pattern from a previous owner. Learned that lesson myself when a buddy's mold kept fisheye-ing and we finally traced it to a candle he'd poured wax into the same bucket he used for mixing.
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