Warning: My old trick for cleaning out a clogged riser tube actually saved the day yesterday.
We were pouring a big batch of aluminum brackets and the riser on mold #7 just wouldn't fill right. I figured the tube was clogged with old sand, which usually means a full stop to chip it out. Instead of grabbing a rod, I took the oxy-acetylene torch and gave the outside of the tube a real quick, light heat pass for maybe 10 seconds. The expansion broke the sand plug loose instantly and we finished the pour with zero defects. Has anyone else tried a thermal shock trick like this on stubborn sand clogs, or is there a better way you use?
Hey @dylanh81, have you ever messed up a trick so bad you ended up with more problems than you started with? I tried this thermal shock idea on a stuck sprue once, but I held the torch on for like 30 seconds and melted the whole damn tube! Luckily it was a small part, but I learned real fast that 10 seconds is the magic number not "until it glows cherry red." Your tip is golden, and I'm definitely using it next time to avoid another embarrassing torch incident.