[SEL] Pouring castings at the Tod Engine Works Class.

[Curt]

Dave,
Glad you enjoyed. Yes the green sand is reused. Core sand is not as it 
is a catalyzed sand (linseed oil and some catalyst).
Yes the muller breaks up clods of used sand and mixes in the water and 
clay you add to give the correct consistency.
Proper green sand will stay in a shape that you squeeze with your hand. 
Too little water and clay and the mold falls apart. Too much water and 
the castings will have too much porosity/gas defects.
You'll find this interesting. I designed the core print on our 
patterns/coreboxes to be the same length as the distance the core is 
cantilevered into the mold. This worked well for 2 of the 3 molds. 
However, on the 3HP Hercules piston, the weight of the cantilevered 
portion of the core was greater than the weight of the core print. This 
resulted in a tipping of the core in the cavity, rather than resting 
neatly in place. I thought I had screwed that pattern up! Clever Rick 
calmly broke off a piece of Styrofoam and placed it in the mold to 
support the core long enough to set the cope flask on. The Styrofoam 
vaporizes instantly when the metal hits it. I thought this was a pretty 
clever solution to one of those "oh shit" moments.

I am learning some new 3D software (SolidWorks) and one of its features 
is that it will tell you the center of mass of a 3D shape. You can bet 
this will be something I use when designing future patterns, assuring 
the center of mass falls within the boundaries of the core print, rather 
than in the mold space. Live and learn!

Curt Holland
Gastonia, NC

Dave Otto wrote:

>Hi Curt
>
>Thanks for the informative update; I have a question about the muller. Can
>the green sand be reused? Is the purpose of the muller to break up all the
>chunky stuff after the sand has been used?
>
>Looking forward to the pictures of your new pistons.
>
>Dave 
>
>
>
>Dave Otto
>Boise, Id
>USA
>Dotto at velocitus.net
>http://community.webshots.com/user/otto1960
>
>
>
>
>
>  
>
>>-----Original Message-----
>>From: sel-bounces at lists.stationary-engine.com [mailto:sel-
>>bounces at lists.stationary-engine.com] On Behalf Of Curt
>>Sent: Monday, April 24, 2006 11:31 AM
>>To: SEL; SEL (Oldengine.org); OFES
>>Subject: [SEL] Pouring castings at the Tod Engine Works Class.
>>
>>Well folks I'm here to tell you that a trip to the Tod Engine Works is a
>>fun and educational day! Wednesday after work I departed for Ohio and
>>got about 7 hours of the 10 hour drive done. Found a local State Park
>>about mid way up in Ohio and slept in the bed of the truck under the
>>stars. Great sleeping weather there as the air is still dry and brisk
>>this far north. Was up early and arrived at Rick's place at 11:00.
>>Got the grand tour of the neat 100 year old building and looked at his
>>mullers, furnace, MG set, ramming lines, and pattern storage area.
>>We began the day by mixing no bake core mold sand in the small muller
>>and filling all the coreboxes. These were set in the sun to expedite the
>>curing. After a couple of hours they were dropped out of the coreboxes
>>and another batch of core sand was mixed and the coreboxes filled again
>>for the other halves.
>>Then we mulled green sand and rammed several patterns.
>>Pig ingots were loaded in the furnace and a heat was begun. 3/4 of the
>>way into the heat, a rubber fitting failed on the water cooling system
>>and a major leak was underway. We nursed the furnace back to safe
>>temperatures, and took the heat exchanger out of the loop for repair. A
>>trip to Lowes and we got the necessary copper fittings to make the more
>>permanent cooling loop. A few hours later and this was complete and we
>>were ready to heat again. But hunger pains were stronger than the drive
>>to pour, so Rick's (very supportive) wife joined us for dinner at a
>>local steak place. We were now properly fueled for the long evening ahead.
>>It takes about 2 hours to heat a cold furnace and contents to be ready
>>for pouring. So about 11:00 the first mold was poured. This was the
>>large Alamo piston and it took all we had melted to fill it, roughly 50
>>pounds.
>>The second heat took about 45 minutes, and we poured the double 1 1/2 HP
>>Hercules pistons, and a single 3HP Hercules piston. We were done at
>>about 1:00 in the a.m. and we were beat. Whew I'm not used to those late
>>hours anymore!
>>We agreed to meet the next morning at 9:00 and we broke the castings out
>>of the flasks. The risers and gating were broken or cut off the castings
>>and they were ready.
>>Unfortunately Missy needed the digital camera for a scouting trip so I
>>was unable to take any pictures, so this tale will have to suffice.
>>But if you are up for a fun day in the foundry you should all consider
>>signing up for Rick's Foundry class before he gets so busy that he will
>>no longer have time for these classes. The proceeds all help him with
>>getting the foundry into full production and with the reassembly of the
>>Tod Engine.
>>
>>I was back home Friday evening and on Saturday began machining on the
>>Alamo piston. I'll post a picture of it when it's done.
>>Curt Holland
>>Gastonia, NC
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>>    
>>
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