Working on some trinkets for my classmates who worked on a boat with me over the summer. We pulled out 100's of bronze screws and a fair amount of bolts and threaded rod. I collected a large coffee can full and wanted to melt it down and cast them a little something from it. I can add some cleaner bronze from another boat if needed. Large part is 3.28 x 1.25 x .165" ( 83 x 42 x 4.2mm)-going to make this one 2-3-4 (?) on a new plate gate is .5 wide x .165" deep (13 x 4.2 mm) well is 1.27 x .75 x .5" (33 x 19 x 13mm), all details in the drag, cope will be sprue and maybe risers draft is 5% or more Wondering if I should be figuring a runner and gate versus gate straight from the well ? Size of runner and gates? I do more aluminum, my last 'home' attempt at bronze froze up before I filled the mold. I will be working with @Uglydog on this so there will be a bigger furnace and more volume and heat. Looking to make a dozen or so, 3 flasks 4-up would be nice. I can switch flask size if needed. Thanks! Three pictures from test print and molding, last one is maybe better gating wise? Edit, statistics per part w/ small gate: Physical Mat'l Bronze, Cast Density 5.127 oz / in^3 / 8.87 g/cmc Mass 2.308 oz / 65.43g Volume 0.45 in^3 / 7.37 cc
I'd make 16 if you want to end up with 12, especially if you have the flasks and sand available. (You can give extras to special guests on your boat.) You could make a second plate with the runner included (narrower than shown, and deeper than the gates) and pour both if it's not too much work to make the second plate. If one is a clear loser, you at least have a second molder on hand so you can quickly re-mold and pour in the same session. You'll also have gained the experience for future pours of similar format. I'm a fan of the runner: there's more hot metal in the mold, and I'm guessing less turbulence going into the casting. Just my 2 cents. Pete
Thanks Pete! Just loaded 4 more patterns into the 3D printer with a wider and offset gate and the intention to use with a longer, end-fed runner. I like the idea of making a couple options, not sure if I will have time for a third plate...if I have the plate from yesterday and one from today there are at least 2 to try.
I printed 5 copies of the bigger badge. 4 are with the bigger gate planned to be 'plated' like this: The other one has the small gate and may replace the smaller one on the test plate. Results to follow in a couple days.
Here's a cope and drag of a set of small flat backs I did back in 2020. Gates didn't need to be that long. Castings came out great. Also shown is my (later) solution to having only one small pattern.
Very nice! I made the 4-up as shown and swapped in a large Skookum for the small one and added a runner to the 2-up plate.
Epilogue: -I ran out of non-rainy weather to pour my bronze at Tamarack and could not linger. They had a pour the next day with 100% usable castings. -I tried molding and casting the patterns here. I had to pack each drag flask twice if not one three times. The sand liked to pull out in between the runner and the badges, especially near the big splash well I added to the test pattern. I used store bought Petrobond for the details in the drag and homemade k-Bond for the copes. Both bins were used with about a pint left over. -Bronze is still a no-go with the small furnace here, I get it melted but not liquid if that makes sense. I did not have a pyrometer in play. I filled the sprue and splash well and the metal froze before I made it to the first cavity of the big mold. I turned the vent into a new sprue and switched over to another crucible and melted aluminum. Everything poured except the cavity blocked by bronze. I do have some issues with the aluminum surface finish, more pock marks/bubbles than expected. Melting stock was tooling plate and old gating.
