New member SW IOWA
- Thread starter Wayne D
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Welcome Wayne, glad to have you.
Depending on exactly how you go about making your cylinder pattern, especially the cooling fins and their draft angle, that would determine the best approach to molding things.
Do you have an ideal in mind about the pattern(s), and what sort of molding sand you want to use ?
I am guessing you will use 356 aluminum ?
Pat J
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Depending on exactly how you go about making your cylinder pattern, especially the cooling fins and their draft angle, that would determine the best approach to molding things.
Do you have an ideal in mind about the pattern(s), and what sort of molding sand you want to use ?
I am guessing you will use 356 aluminum ?
Pat J
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I have petro bond sand that I use. I do not know about patterns yet I have been looking at You Tube at modelers that cast their on parts for IC model engines. I use old car pistons from a local engine shop to cast with, I had heard this is a good alloy.
Wayne
Wayne
This is how I have seen one guy cast full sized motorcycle cylinders.
For a small model airplane cylinder, it may be quite challenging to pull the pattern from Petrobond.
This guy uses bound sand.
https://www.homemodelenginemachinis...se-casting-motorcycle-racing-cylinders.35502/
A more difficult approach is to use the investment method, but that would be pretty tedious, with burnout, special ceramic slurry, etc.
I have not gotten into investment casting, just because it is a multi-step process, and rather complex.
I do use bound sand for all my molds, and I guess that would be my approach if I were going to make a model airplane engine.
I would use bound sand for the cores and molds.
Seems like I have seen an example cast on this forum somewhere; I will look for it.
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For a small model airplane cylinder, it may be quite challenging to pull the pattern from Petrobond.
This guy uses bound sand.
https://www.homemodelenginemachinis...se-casting-motorcycle-racing-cylinders.35502/
A more difficult approach is to use the investment method, but that would be pretty tedious, with burnout, special ceramic slurry, etc.
I have not gotten into investment casting, just because it is a multi-step process, and rather complex.
I do use bound sand for all my molds, and I guess that would be my approach if I were going to make a model airplane engine.
I would use bound sand for the cores and molds.
Seems like I have seen an example cast on this forum somewhere; I will look for it.
.
This one looks to be machined from bar stock, perhps CNC ?
https://www.homemodelenginemachinis...morton-m5-engine-cylinders.25610/#post-280469
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https://www.homemodelenginemachinis...morton-m5-engine-cylinders.25610/#post-280469
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Grabcad has one 4-stroke.
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Seems like I have seen some old-school model airplane 4-stroke engine designs, but I can't find an example.
Here is a Saito FA-120 cutaway engine (not my photo).
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Here is a Saito FA-120 cutaway engine (not my photo).
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Here is another crankcase casting.
Casting the crankcase would be easy, and you could core it also without much trouble.
Casting a cylinder and/or cylinder head with fins would be more challenging, especially at a small scale.
The head would be easier to mold than the cylinder.
When you get into this small of a scale, you may need to think about investment casting, or a lost wax/PLA casting.
I have seen some amazing castings from the hardware store lost foam method, but not on a small scale.
The hardware store lost foam method is a rough approximation of the expanded beads used for commercial lost foam castings, and so don't expect as good of results as the expanded beads if you use hardware store foam.
The hardware store lost foam method also fills very slowly, and I wonder if there are cold joints in the metal, especially if two metal wave fronts meet deep in the mold.
For a model airplane engine, you are going to need a high degree of casting structural integrity, due to the vibration that it will have to withstand, and I am not sure the hardware store foam method would be up to the task.
I am not aware of the big hardware store foam guy on youtube ever making an operating engine; he makes cylinders, manifolds, etc., but I have never seen a real operating engine built by him, and so I guess his cast cylinders are just for show ?, or perhaps he just does not publish his engine work.
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Casting the crankcase would be easy, and you could core it also without much trouble.
Casting a cylinder and/or cylinder head with fins would be more challenging, especially at a small scale.
The head would be easier to mold than the cylinder.
When you get into this small of a scale, you may need to think about investment casting, or a lost wax/PLA casting.
I have seen some amazing castings from the hardware store lost foam method, but not on a small scale.
The hardware store lost foam method is a rough approximation of the expanded beads used for commercial lost foam castings, and so don't expect as good of results as the expanded beads if you use hardware store foam.
The hardware store lost foam method also fills very slowly, and I wonder if there are cold joints in the metal, especially if two metal wave fronts meet deep in the mold.
For a model airplane engine, you are going to need a high degree of casting structural integrity, due to the vibration that it will have to withstand, and I am not sure the hardware store foam method would be up to the task.
I am not aware of the big hardware store foam guy on youtube ever making an operating engine; he makes cylinders, manifolds, etc., but I have never seen a real operating engine built by him, and so I guess his cast cylinders are just for show ?, or perhaps he just does not publish his engine work.
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