I'm considering trying a vertical pour for a small dagger, slender, 8". Any suggestions for venting, is it better to pour from the small end, point, or the pommel. I'm thinking pommel end would put more pressure to the more slender blade of the pattern. Question is how to vent and prevent air inclusion. Thanks for any suggestions, John,,,
I went vertical on a piece that I was having trouble with shrinkage. Solved the problem. https://forums.thehomefoundry.org/index.php?threads/exp-styrofoam-followers.1254/
It's somewhat related but I've been involved with horizontally pouring a pair of bronze Hmong Temple swords a while back: We just had an A20 crucible with bronze so hot it was burning the tin slammed it into a large pouring cup with a bit of height or head to give hydraulic pressure as the bronze cooled. A larger crucible size will retain heat in the bronze for a lot longer as the volume vs surface area is increased, I can notice the difference between an A16 and an A20 when pouring bronze. They were at least a metre to 1.2 metres long. For a dagger you'll need the bronze to be super hot/boiling and slam it down the sprue to get it to travel any distance. https://forums.thehomefoundry.org/index.php?threads/hmong-temple-sacred-swords.116/ Edit: some phos-copper will also increase the fluidity of the bronze before pouring.
Lee the temple priest in the sword casting photos had several items like temple bells cast using sacred bronze that had to be prayed over for two years and which could not be touched by women lest it discharge all the hard work praying. Lee would turn up with some pattern we were sure would not cast and light three candles during the casting session and the castings made would invariably turn out perfectly fine. So after a while it became a measure of how difficult a casting would be to make, i.e. "Ooooh that's a four candle job for sure!" .
Well, I'm smarter than I was a bit ago,,, Gives me an idea, think I'll offer a cold beer to Hephaestus for a good pour. Of course I'll have to symbolically drink it if it works,,,,, maybe 2 or three if it don't....
