I stumbled across a set of videos showing the details of sand casting methods used to produce the cast ductile and grey iron street light poles, utility boxes, and luminaries used by many municipalities across the country and inernationally. There were several points of interest for me: 1). Loose pattern pieces and their application was demonstrated. 2) The application of chaplets was shown. 3). Swing grinding castings was demonstrated 4). Simultaneous pouring from dual gates into the same mold is used. 5). Roll forming of steel tubes was shown. One safety point of interest struck me. In several instances there were closely spaced groups of raw or finished 15 foot tall castings standing on narrow unsecured side by side. If there were an earth quake or if a fork lift operator bumped one of those castings, there would be a whole lot of metal flying around.
I have seen retracts used a number of times in industrial patterns, but can't recall them being used by the backyard crowd, although I am sure someone has used them. I have seen them in an old book about how to cast a steam whistle. I will start a post, located here: http://forums.thehomefoundry.org/index.php?threads/patterns-for-casting-a-steam-whistle.267/
I am pretty sure one of the more experienced people who posts here has used loose pattern pieces in one of their vids. Nevertheless, seeing another application of them was very informative for this noob. Also seeing the methods used to efficiently manipulate heavy castings was interesting.
Always good for a re-watch, those spring city videos. They really do show some interesting molding concepts. I've found they're not easy to find by searching for them when you're actually looking for those videos in particular either; I have a theory that you can only get to them by random chance. So thanks for posting this! Jeff
Ah, “re-watch.” I was afraid they had previously been posted or maybe even several times posted. But, a google search of AA and THF did not uncover them.
I just spend way too much time watching foundry videos on YouTube, is all... http://forums.thehomefoundry.org/index.php?threads/a-nice-iron-casting.158/ There's one posted there, but like I said - these videos seem to defy searches, so having some of them linked up in different places is always welcome as far as I'm concerned. Jeff