10-20-2016, 06:34 AM
First casting and first failure!
I clearly have a lot to learn with this home foundry thing; but I guess if it was easy everyone would be doing it.
I at least managed to get a pattern made and a flask rammed. The pattern is for the broken power-feed gearbox for the Victoria U2 mill.
First rammed half the pattern in the drag
[attachment=13794]
So far so good, put the cope on and rammed the other half, had a little sand-sculpting to do after pulling the patterns
[attachment=13795]
The finish in the cavities was not as good as i would have liked, not sure why but some loose grains came away with the pattern and left a bit of a pock-marked cavity. Also I think the flask was just a tiny bit too small for this pattern, the sprue and riser are very close to the cavity.
[attachment=13796]
I couldn't see into the furnace with it running, wasn't sure whether I had the crucible filled. When I started the melt I was confident I had plenty of aluminium on hand but I started to worry I didn't have enough, I was hunting out little morsels of scrap aluminium to drop in.
When I shut the burner down and opened the furnace, the crucible was overflowing. Even so, the pour was waayy short. Only half-way up the sprue when I ran out of metal. Going to have to make a bigger crucible for aluminium, this was my biggest carbon-graphite crucible, A8.
Poured the flask on my moulding bench, not sure that I'll do that again- hard to keep the burnt sand separate when breaking out.
[attachment=13797]
Here's the casting, obviously short but any thoughts on why the surface looks so awful would be welcome.
[attachment=13798]
[attachment=13799]
[attachment=13800]
[attachment=13801]
[attachment=13802]
[attachment=13803]
I'll be interested to cut into this and see whether it is porous. At least failures can be melted down. I have a couple of transmission housings that I need to break into useable pieces so I don't run out again during a melt; need to pay more attention to calculating quantities in future too. It looked like a lot of aluminium before I poured it!
I was thinking of putting a core in this casting but decided to keep it simple for a first attempt. I guess it wouldn't have poured short if I had put a core in it; might have to look at that for the next attempt.
I clearly have a lot to learn with this home foundry thing; but I guess if it was easy everyone would be doing it.
I at least managed to get a pattern made and a flask rammed. The pattern is for the broken power-feed gearbox for the Victoria U2 mill.
First rammed half the pattern in the drag
[attachment=13794]
So far so good, put the cope on and rammed the other half, had a little sand-sculpting to do after pulling the patterns
[attachment=13795]
The finish in the cavities was not as good as i would have liked, not sure why but some loose grains came away with the pattern and left a bit of a pock-marked cavity. Also I think the flask was just a tiny bit too small for this pattern, the sprue and riser are very close to the cavity.
[attachment=13796]
I couldn't see into the furnace with it running, wasn't sure whether I had the crucible filled. When I started the melt I was confident I had plenty of aluminium on hand but I started to worry I didn't have enough, I was hunting out little morsels of scrap aluminium to drop in.
When I shut the burner down and opened the furnace, the crucible was overflowing. Even so, the pour was waayy short. Only half-way up the sprue when I ran out of metal. Going to have to make a bigger crucible for aluminium, this was my biggest carbon-graphite crucible, A8.
Poured the flask on my moulding bench, not sure that I'll do that again- hard to keep the burnt sand separate when breaking out.
[attachment=13797]
Here's the casting, obviously short but any thoughts on why the surface looks so awful would be welcome.
[attachment=13798]
[attachment=13799]
[attachment=13800]
[attachment=13801]
[attachment=13802]
[attachment=13803]
I'll be interested to cut into this and see whether it is porous. At least failures can be melted down. I have a couple of transmission housings that I need to break into useable pieces so I don't run out again during a melt; need to pay more attention to calculating quantities in future too. It looked like a lot of aluminium before I poured it!
I was thinking of putting a core in this casting but decided to keep it simple for a first attempt. I guess it wouldn't have poured short if I had put a core in it; might have to look at that for the next attempt.