1/16/2024 0 Comments Lost foam casting plasterWhat I came to understand was unbound sand really isn't unbound. Positioning and gating LF patterns can be a bit nebulous. I was kind of amazed the contraption still worked! The center was a little eccentric, so I'll try again Monday wih some adjustments. Hooked up an old Win 98 laptop through the printer port, and actually cut the same dimension foam out. I then swept the dust and mouse droppings of 8 years off of a CNC foam cutter I built out in the big shed. Sanding with 220 was no problem, the paper didn't load and the seams sanded flush. Worked well, though the hole saw left a fairly coarse finish compared to the Forstner. Today I cut out some foam pieces with a 1-1/2" hole saw, and drilled them 1" with a Forstner bit, and glued them together with good old rubber cement. It does smooth surfaces nicely, and can really take the heat. I do have some Satanite and could wash the cup with that to get fancy. Like you say, probably just plain sand and fireclay, baked into a pouring cup, makes the most sense, and is easy. Thanks HT1, I am now thinking of just making a few small samples of materials shaped like angle-iron ingot molds, and pouring a little iron into them to see how they handle it. I'd like to try both again, I'm sure the variables are all different now, so not necessarily the same result. I'm not saying that this is always true with all brands of compound, all molders, and all metals, just what I experienced with what I had and did then. And a blob of hot glue which was used to attach the sprue to the pattern is also preserved in perfect detail on the left." Polystyrene was pulled out of the mold by absorptive plaster of Paris allowing the metal to cool against the mold sides and record the very fine detail of the foam texture. "On the right you can see that the actual texture of the foam has been recorded and transferred to the metal. The drywall compound was not absorptive and the plastic stayed inside the mold. "On the left the zinc separated from the mold walls by layers of molten polystyrene. "This morning with the sun coming in low through a window it was possible to highlight the difference in surface finish and detail fidelity of the second casting and the third (last) one. plaster of Paris vs Wallboard compound in zinc. I was also just mentioning my own experience re. I definitely would have dried it to get rid of bound water - Chastain recommends a minimum of 400F. 1", and yes you're right, for melts including cuprous metals, not iron. I just looked it up again and The reference is to riser sleeves In Chastain's "Metal Casting: A sand Casting Manual For the Small Foundry Vol. Hi Kelly, I wouldn't have made a cup of plaster without first checking the reference, I was just wondering about something I'd remembered.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |