I support the others who suggested using old castings Brian. Extrusion alloys shrink badly! I also like HT1's suggestion to ingate from one end, Cheers Charlie
Thank you, you beautiful bastards. It's been a month since I posted this thread and thanks to all of your recommendations, I have been able to reliably and (more importantly) consistently produce clean, unblemished, perfect casts. This is my current set up with a new flask, one made to accomodate a vertical pour. One end can swivel open when I'm ready to pour. I'm still fluxing and de-gassing like my prior castings, just to make sure I get every melt as pure as I can, and getting a read on melt heat for optimal pour consistency. That was definitely one issue I was having before gauging by eye and gut, my melts were way too hot. No needing to make blind risers, prick vents into the negative, no more wasted metal in extenders: It's 100% every time. Pictured here was my last aluminum cast with extruded metal. I've got 356 alu now (as pures as I can get, anyway) and have been using that, and it looks to be the same results as the extruded alu although I'm sure mechanically it's more sound if this is meant to be machined. I can't tell you how much I'm indebted to you folks. All of your input has saved me a lot of time and heartache, and potentially more gray hairs, trying to slowly piece together what I need do better. I really am very thankful. Thank you all so much.
Well shit, I better go back and re read the thread then! Lol. I like the idea of being able to open the end of your flask. I would strongly recommend covering the sides though. It's only a matter of time before your sand collapses out the sides (vertical faces). Pete
I mentioned this in passing when I wrote the Post, but yes, you gotta throw a piece of Plywood on each side of that flask, clamp it on with cheap Harbor freight clamps, and carry on Well Done V/r HT1
I know its old but if you decide to cut the aluminum with a skill saw use wax on the blade. Makes it cut much better...just clean it off before you melt it.
....and on carbide burrs and abrasive belts. Helps keep the burrs from loading up, especially on gummy castings. I had a knife grinder friend tell me to use stick wax on my abrasive belts for metal work and I thought he was crazy, but wow, what a difference when grinding and shaping metal........way less heat and faster cutting... Best, Kelly
Does it matter what kind of wax? I only use cutting lube so far for, well, cutting. Oh, and this was the result from all the trial and effort I've done, and continue to do.
Everyone has their favorite brands but all are very similar. Just search stick wax, tube wax, cutting lube. If you already have cutting lube that's a soft solid in a tube, it's likely the same stuff. Best, Kelly