Ball Hopper Monitor - Casting Project

[GreenTwin]

Well, before you try the moonlight requisition.....

The next time she goes to the store ask her to get a box of cornstarch. Tell her you need some for an experiment, which ain't a fib. Tell her she can have the new stuff and you'll take the old stuff, also not a fib. Happy wife => happy life.

My wife was all good with the foundry stuff until the flames started in the backyard.
She has been suspicious ever since.
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[Fidlstyks]

I use wood flour in my cores. With Linseed oil, funny the more water I use, the harder the baked core

 

[Fidlstyks]

I stop at the Amish Cattail Foundry in Lancaster Co Pa.
They use a coupola with short sprues and no vents. I vent every thing. I use the vents for cast iron welding rods
I like taller sprues, they fill molds better.
The book I have says to make the iron swirl going down the sprue hole.

 

[GreenTwin]

I use a short sprue typically, but I use vents at the high points of the mold.
With greensand, I have seen some get away with no vents, due to the permeability of the sand.
Not a good idea with bound sand to leave out the vents, as I have found.

The sprue on the water hopper is going to be taller than I like, but there is nothing I can do about that.
A tall sprue increases the velocity, but that is probably a necessary evil in some cases in order to fill the mold completely.
There are tradeoffs in casting work.

The swirl would seem to be bad, since that would suggest turbulence, but I think any fluid poured down a sprue is going to swirl, regardless.
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[GreenTwin]

I asked my wife if we happened to have any corn starch.
Her completely predictable response was "Why do you need corn starch?", as if that were really relevant to the grander scheme of backyard casting endeavors.
Translated, that means "are you getting into my kitchen stuff again for that foundry stuff you are doing in the back yard with the big flame ?".
I said "Its to reduce the strength of the filler".
I am not sure she understood my explanation, but she did give up the corn starch without further interrogation.

So now we try some corn starch/Fastpatch experiments.
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[GreenTwin]

"Operation cornstarch" test is underway.
I mixed it 50/50, which is probably an excessive amount, but ok for testing purposes.
Hopefully nobody will notice the missing measuring cup until the experiment is complete.
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[ddmckee54]

Yeah, for some reason most wives don't really see the need for having your own personal backyard flame-thrower. Go figure.

At a 50/50 mix it might be really soft and crumbly when dry.

 

[Fidlstyks]

Are you going to use cast iron or aluminum,?
We discussed alumimum and velocity before, in aluminum, I ment more at hydrostatic type of pressure, pouring rate with aluminum is said to pickup hydrogen. I need to study that.
I think castiron likes it. But iron burps the air, I even like my vent lower at times. I think it creates hardspots when on a tip, and velocity helps fill molds.
I think velocity helps with brass too.
My castiron pours like water.

 

[GreenTwin]

I have a heater blowing on the test piece.
It smells like something is cooking.
If the wife asks about the smell, I will have to come up with some sort of evasive answer.

I will mix up a 70/20 mix and see what that does.
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[Fidlstyks]

"Operation cornstarch" test is underway.
I mixed it 50/50, which is probably an excessive amount, but ok for testing purposes.
Hopefully nobody will notice the missing measuring cup until the experiment is complete.
.

What are you mixing with corn starch, half would be too much for anything. I have a formula from a CW Amen book for cores. I can look for it. But the wood flour works better.

 

[GreenTwin]

Are you going to use cast iron or aluminum,?
We discussed alumimum and velocity before, in aluminum, I ment more at hydrostatic type of pressure, pouring rate with aluminum is said to pickup hydrogen. I need to study that.
I think castiron likes it. But iron burps the air, I even like my vent lower at times. I think it creates hardspots when on a tip, and velocity helps fill molds.
I think velocity helps with brass too.
My castiron pours like water.

My permanent pattern halves for the water hopper will be castin in 356 aluminum, and one way to solve fill problems is to increase the pour temperature a bit, to allow a longer fill time without solidification.
The tradeoff of elevating the pour temperature much above 1,350 F is that the surface finish can become more rough, and also the longer the melt is heated after reaching 1,350 F, the more hydrogen it absorbs.

One the permantent pattern halves have been cast, then I will use those to make a full mold, and cast that in gray iron.

I can superheat aluminum very easily, but I don't really know what is happening temperature-wise if I continue to heat iron for over an hour.
I don't have a good way to measure iron temperature, but from what others have said, an oil-fired furnace has a typical iron pour temperature in the 2,400-2,500 F range.

I have noticed that if iron is heated beyond what is required for a complete melt, it does begin to emit sparks out the lid opening, and I interpret this as a sign that the melt has increased significantly in temperature above 2,400 F.

The ferrosilicon helps make the iron more fluid.
Too much ferro causes excessive shrinkage and hot tears.

If a iron scrap that contains phosphorus is used, such as old radiators, the fluidity goes up a lot, but supposedly at the expense of having a metal that is not as strong as Class 30 or 40 gray iron.

The art-iron folks who use a cupola seem to get some really hot and fluid iron, and so that iron may be above 2,500 F.

Are you using an oil-fired furnace, cupola, or induction furnace?
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