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JCDammeyer's 42 projects

jcdammeyer said:
I don't why but I've had this fear of melting metal over the last 4 years or so. The last pieces I cast were the frame for the Pneumatic Power Draw Bar that worked but not the way I wanted. I then made new patterns but never cast them And an even older pattern for the harmonic drive 4th axis. And patterns for the newest distraction to avoid other projects; the AR3 robot arm.

Anyway, even though it was about 24C outside with not much breeze I finally bit the bullet and set up to make ingots from Hyundai intake manifold and other sawn up bits.

View attachment 84502

Because the pieces are large I used the pipe crucible that can hold 12 lbs of aluminum. About half full for each set of ingots. All told the end result was 10 lbs of ingots.

View attachment 84503

By then I was puffing and really out of breath. And bending over a hot cruicible to fish out the left over steel bits from the castings. A lot of dross on top too, some of which might have been good metal but to make the ingots I didn't bother with degassing. Not even sure what sort of flux I might use and if it would separate some of the dross.
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BTW, the Pipe Crucible and holder weighs in about 17 lbs. Add in 8 lbs of metal and it's a heavy lift when it's full of 750 degree C metal.
PipeCrucible_Handle.jpg
 
jcdammeyer said:
Thought I'd test out pattern for the pouring basin. Still have to make a smaller tapered sprue form but the basin looks good. Hopefully less porosity in the castings.
View attachment 84555
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Hey John, ever use steel ‘chills’ to help cooling thick cross-sections of a casting ?
We used a number of them when we were casting moulds for corrugated pipe.
 
LenVW said:
Hey John, ever use steel ‘chills’ to help cooling thick cross-sections of a casting ?
We used a number of them when we were casting moulds for corrugated pipe.
Click to expand...
Not sure I've done anything thick enough that needs that. Got any interesting links on that sort of process?
 
LenVW said:
Here is a NA company with Asian Production facilities that explains the use of ‘chills’.

alignmfg.co

Cooling and Solidification: A Delicate Transition

Learn how to control cooling rates to produce high-quality castings with optimal properties. Understand the factors influencing solidification and prevent defects.
alignmfg.co alignmfg.co
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Interesting. Haven't read through all of it yet but does beg the question. This is a pattern for a small box for the AR3 robot arm. The edges and the bottom are all the same thickness but there's the step at one end.
1784593480543.png

This has lots of things wrong here but it was really a trial. The cope/drag are too small. The sand is too wet. Added too much water to the sand. Used too much parting dust.

Anyway, the idea here is to put a riser above the shelf part. This is the thickest part of the casting and would likely shrink down. That would be the back of the box and of no consequence but with the idea of not having shrinkage at all seems like the riser there and feed from the opposite end.

Or would a chill be a better idea?

1784596588303.png
 
jcdammeyer said:
Interesting. Haven't read through all of it yet but does beg the question. This is a pattern for a small box for the AR3 robot arm. The edges and the bottom are all the same thickness but there's the step at one end.
View attachment 84569

This has lots of things wrong here but it was really a trial. The cope/drag are too small. The sand is too wet. Added too much water to the sand. Used too much parting dust.

Anyway, the idea here is to put a riser above the shelf part. This is the thickest part of the casting and would likely shrink down. That would be the back of the box and of no consequence but with the idea of not having shrinkage at all seems like the riser there and feed from the opposite end.

Or would a chill be a better idea?

View attachment 84570
Click to expand...
The feeder riser should be right where you are planning, above the ‘step’.
As for the CHILL, I would make the entire end of the FORM a machined ‘negative’ of Mild Steel.
It would act as a HEAT SINK when you have poured the molten metal.

You have to keep in mind that my knowledge of casting is of LARGE aluminum mould blocks which were 18” wide x 36” deep x 64” high. (We used them to produce 44” diameter corrugated HDPE pipe)
 
LenVW said:
The feeder riser should be right where you are planning, above the ‘step’.
As for the CHILL, I would make the entire end of the FORM a machined ‘negative’ of Mild Steel.
It would act as a HEAT SINK when you have poured the molten metal.

You have to keep in mind that my knowledge of casting is of LARGE aluminum mould blocks which were 18” wide x 36” deep x 64” high. (We used them to produce 44” diameter corrugated HDPE pipe)
Click to expand...
These are the largest (in mass) that I have cast. Required the 12 lb pipe crucible as opposed to the 6 lb. Most everything I've done is under 6 lbs.
LargeCastings.jpg
 
jcdammeyer said:
These are the largest (in mass) that I have cast. Required the 12 lb pipe crucible as opposed to the 6 lb. Most everything I've done is under 6 lbs.
View attachment 84623
Click to expand...
Chills help to remove ‘heat’ from sections that are thicker than the adjacent sections.

The ‘step’ in your rectangular casting (Monday 9:20 PM post) is a perfect example of a ‘pour section’ that would retain a larger quantity of thermal energy. The larger volume of metal in the step would require the ‘additional cooling’ that a ‘chill’ would provide.
 
Yahoo. We expected up to 3 days to have our UK ETA documentation processed. Instead it took longer to use the app and photograph the passports (and ourselves). Payment confirmation and UK ETA confirmation arrived pretty well right after each other.

Now to figure out where else in Ireland we're going to stay and how much of Northern Wales to visit. We've already booked a week in London. Already seen the museum with the big steam engine.
 
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