Casting Kindergarten

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nobbie48

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Needing to waste brain and shop time I decided to cast a small part. It's actually a part for a bicycle but I don't know if there are any motorcycle parts that would benefit from my first time experience.

Part 1 was to make a plug for the oximeter holder from body filler. I taped the body of the oximeter with Scotch tape and pushed it into some mixed filler. In a few minutes the filler had set and was reading to be trimmed. I unfortunately made one wall too thin but carried on regardless.
 

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The next step was making the female mold with the special sand (Amazon)
 

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I didn't have enough heat or a proper crucible so instead of casting in aluminum I used aluminum brazing rods, melted with propane in a small cast iron ladle. Pricy but the melt temperature is a lot lower and since the quantity was low, I went for it. The thin wall didn't let the metal to flow properly but it shows proof of concept.
 

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A bit of grinding and buffing shows the concept workable.

In my case, I've always wanted to cast something in aluminum and this was small enough for a first effort. I've got to see if I can come up with a crucible that fits my inductive heater and try again with a better starting plug. Also the brazing rods are denser so the part is heavier than needed.

I'm throwing this out in case someone needs a simple replacement cast part for their bike. I don't recommend my method for pistons or a sand cast Honda 750.
 

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Cool but why? 3d printer is probably faster and cheaper and most definitely much lighter.

How hard are you working on a bicycle that you want to monitor pulseox often? It really shouldn't be dropping much. Heart rate is normally a solid indication of your output vs what you are capable of.
 
GreyGhost said:
Cool but why? 3d printer is probably faster and cheaper and most definitely much lighter.

How hard are you working on a bicycle that you want to monitor pulseox often? It really shouldn't be dropping much. Heart rate is normally a solid indication of your output vs what you are capable of.
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Sometimes I just want to try something different and I wasn't going to try an engine block. The bracket was the right size.

3D printing or CAD / CAM would mean buying equipment I don't know how to use. Another option would be casting the thing in resin.

The high school I went to had a foundry class but shut it down in the mid 1960s because only one person took it as a major.
 
More playing around. I’m still having problems with thin sections but I managed to cast a spare key for the cage. It’s ugly but works.
 

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I did some cast aluminum parts a few years ago , built the blast furnace from a small pile of firebrick and used a pizza stone as the top cover , turkey fryer burner with a blow dryer to turbo charge the flame. There was a foundry supply place (now closed) in Milton that had the secret sand , it has some clay base so it stays molded . The aluminum I used was scavenged pieces of already cast aluminum so I knew is was mostly the right kind and castable. There are many different "strengths" of aluminum for casting depending on what your making as I have learned, and the more defined you can make the mould , ie; holes where pins or bolts may go , the less machining after. Wear a respirator since you have no way of knowing what crap went into the pot your melting , none of it is good for you.
 
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