it was rammed up last night out of the oil sand that I have been trying to quit being so damn sticky, the blade had a crack that goes almost all the way across it and I taped one end of the crack the outline of the tape can be seen in one picture I also have tape on the two holes but they were there to start with. I used metal duct tape to cover em over ( if the regular duct tape won't work get the metal good stuff). I covered the part in commercial parting compound from Freemans Foundry Supply, covered it with riddled sand stright from the muller. packed it down so that I knew the part was covered with clean lump free sand. Then filled and rammed it up with the cutoff end of a sledge hammer handle till it was full.
II then flipped the flask half, dug the ends of the blades out of the packed sand, the blades don't come out flat on the table the ends are cut at an angle. Covered in Parting Compound, put on the drag half of the flask, put in some riddled sand then filled and rammed in lifts till it was full. Flask is a total of 8 inches deep, could be cut in half.
I then flipped the thing so it was sitting on the drag pulled the cope or top half, pulled the pattern (it looked a lot smoother then it came out) used a piece of 062 tig rod to vent the blades out the top. Did some clean up work on the center hub area, cut a half inch sprue hole and a pouring basin then closed it up, parked it in the shead over night.
Got up this morning, made coffee, fired the furnace and cut the sprue off of the last flask side, and gathered up some other sprues and such broke em up to fit in crucible, brought out the mold, readied the flux tool with flux and degasser. Melted a #4 full, when I thought it was hot, I plunged in the flux/degasser, till it calmed down, cleaned the top of the melt, and poured, it filled so fast that I was afriad that it poured cold or shut. But when I pulled the cope off and flipped it over I saw that I had a 100% pour on the outer rim of the blade. I'm not real happy with the surface finish, remember that this was molded off of a plastice fan blade. It should of came out smoother.
Specially on the vertical surfaces of the blade. there was nothing in the mold to cause the roughness on them that there is, other than the sand.
It was a good moment and feeling when I pulled the part completely out of the sand to see that I had an almost complete pour. two of the blades likes just a smidge of filling completely. but otherwise it is a useable part I think.
I want to thank 4cylndrfury, Harry, and Nudge for the help that they gave in me completeing this to the point that I got a useable part out of it. now for something a little harder. After I get back from Argentina.
Fan Casting
Re: Fan Casting
David and Charlie aka the shop monster
If life seems normal your not going fast enough" Mario Andrette
If life seems normal your not going fast enough" Mario Andrette
Re: Fan Casting
Another trip planned huh? Have fun and stay away from the bad parts of town.
A couple of things in what you were talking about. You mentioned leaving the mold to pour the next day, I often do this also with molds sometimes sitting for several days. Make sure you lay something over the sprue hole so a spider cant crawl in there.
On making the flask thinner, this is a great way to save a lot of work by reducing the volume of sand used but remember to provide head pressure as this is what will help a great deal in filling thin sections. A piece of pipe with sand in it with a hole poked through works great. I made a little cone to form a pouring cup when making my sprue risers.
On the surface finish being a little rougher than you had expected. I think lots of things can cause this from the metal, temperature, sand and of course the mold itself. One thing you might want to try if you are going to cast it again is ramming harder, I mean really get the sand packed in on those blade edges, this being a thin part though and plastic not to mention already cracked this might be a problem. Getting the sand packed really tight though can make a difference in the finish and I am suspecting because of the reasons mentioned concerning this particular pattern you might not have been able to get all of the voids tightly filled with sand.
Still I think it came out great and with very little cleanup will serve you well... Try and have some fun on the trip, all work and no play makes Jack a very dull boy.
A couple of things in what you were talking about. You mentioned leaving the mold to pour the next day, I often do this also with molds sometimes sitting for several days. Make sure you lay something over the sprue hole so a spider cant crawl in there.
On making the flask thinner, this is a great way to save a lot of work by reducing the volume of sand used but remember to provide head pressure as this is what will help a great deal in filling thin sections. A piece of pipe with sand in it with a hole poked through works great. I made a little cone to form a pouring cup when making my sprue risers.
On the surface finish being a little rougher than you had expected. I think lots of things can cause this from the metal, temperature, sand and of course the mold itself. One thing you might want to try if you are going to cast it again is ramming harder, I mean really get the sand packed in on those blade edges, this being a thin part though and plastic not to mention already cracked this might be a problem. Getting the sand packed really tight though can make a difference in the finish and I am suspecting because of the reasons mentioned concerning this particular pattern you might not have been able to get all of the voids tightly filled with sand.
Still I think it came out great and with very little cleanup will serve you well... Try and have some fun on the trip, all work and no play makes Jack a very dull boy.
I'd rather laugh with the sinners than cry with the saints the sinners are much more fun...
Muller
Muller
Re: Fan Casting
knowing what I know about that part of the world there will be no time for david, all I want to do is go fix and come back and do it as fast as I can.
Anyway I plan on recasting the fan blade several more times, I think its a good learning tool. something small not tiny, but not large its only about 5 inches in diameter. You may have something in ramming it harder, but like you said its plastic so I have to figure out some way to ram harder without destroying the pattern, maybe is I ram the top flip it ram the bottom, flip it seperate and put on some more parting then ram it again hard, it may be that its just this sand being new with no burned sand in it. I think I may cast and pour a backing plate out of cast iron in the morning that way I can get some charred bits in the mix. And besides I haven't melted any iron in a while. and a spare face plate is always nice to have laying around. I need to make one 12 inches and us it for a disk sander.
David
Anyway I plan on recasting the fan blade several more times, I think its a good learning tool. something small not tiny, but not large its only about 5 inches in diameter. You may have something in ramming it harder, but like you said its plastic so I have to figure out some way to ram harder without destroying the pattern, maybe is I ram the top flip it ram the bottom, flip it seperate and put on some more parting then ram it again hard, it may be that its just this sand being new with no burned sand in it. I think I may cast and pour a backing plate out of cast iron in the morning that way I can get some charred bits in the mix. And besides I haven't melted any iron in a while. and a spare face plate is always nice to have laying around. I need to make one 12 inches and us it for a disk sander.
David
David and Charlie aka the shop monster
If life seems normal your not going fast enough" Mario Andrette
If life seems normal your not going fast enough" Mario Andrette