One Sided Molding

From molding systems to gating, what goes on at the molding bench will make or break a casting.
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Harry
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One Sided Molding

Post by Harry »

Been thinking about this for awhile and I think I am going to give it a try on one of my smaller flasks and if it works well scale up.

What my idea is is to make a molding board of sorts from dense castable, maybe an inch and a half thick and the size of the perimeter of the flask. I would fire this brick then use it as the drag with the part in the cope. Thinking it might work out well for a few parts and save a drag on every one cast. Two concerns are the aluminum eating up the refractory making it rough an just cracking it when pouring the aluminum onto it while cold.

Along these same lines I have also been thinking about getting some thick steel plate cut for the various flask sizes and using that. Of course the refractory would be cheaper and I have some on hand so I will try it first.
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Re: One Sided Molding

Post by HT1 »

unless you preheat the "none" sand you use as a drag, you will have cold shut problems, especialy with the steel . ever cast fishing weights in an aluminum mold, the mold has to be preheated, or it will not fill, same concept. remember sand is an insulator
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Re: One Sided Molding

Post by Harry »

Kind of figured on that HT and I believe it will depend on a part by part basis. I think thicker section parts should flow enough heat in to overcome the chilling, I mean chills are often used in a sand mold for this reason. I agree the steel would also be more likely to cause issues at least on the first pour but if doing several in a row the first will have the steel hot for the rest of the run. The refractory I am just concerned about eroding and losing surface quality but we shall see on that, might be worth replacing every XX number of pours and the used tiles could be used for foundry floor once I have a collection of them.

Another consideration is handling the poured molds, wont be able to pick them up and carry to the shakeout because the part will fall out of the bottom taking sand with it. It could be slid into a steel pan though to move to the shakeout.

I am just looking at ways here to reduce time and sand use. I suppose it might be better to look more into vertical molds by setting up flasks for it and using the back side of one as the flat of the next clamping them together in a row. Always trying to figure out ways to increase production and reduce effort/time.
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Re: One Sided Molding

Post by HT1 »

I see your point, I try to thin out my parts to asve metal, many of my plaques are at the minimum thickness already, anything that chill at all would be bad, you might get away with more.

Lets not talk about chills too much, that is a HUGH subject, I have used them once or twice, and have used Zircon sand to encourage directional cooling more.

You could preheat the steel plate, but if you get it too hot, it will damage the sand part of the mold, so there will have to be some serious controls involved, and if anyone can pull that off it would be you.
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