what I casted today

[dallen]

I was ask yesterday about the size of sprue cutter that I use. I use what is known in the dessert trade as a Cannoli tube, its a metal tube of varying sizes that is used to make a dessert pastry on. I find that its the right size for most of the metal casting that I do. I also have a variety of different tubes that I use which range in size for a small 3/8 brass tube up to a hunk that I cut out of a extension tube for a vacuum cleaner which is 1.250 in diameter.

I've watched a lot of youtube videos and have seen people using all kinds and sizes of tubes to cut sprue holes in casting molds with. most use the handy dandy sink drain tube cause its thin, cheap and makes a hole thats around and inch and a quarter in diameter. But not all molds can use the same size sprue hole, or in a better way of saying it is that not every mold needs the same size sprue hole, same as not every mold can use the same gating.

The castings that I have made in the last few days some of them were poured more then once because of different problems. mostly shrinkage or the sand tearing when opening the mold to remove the pattern. I remolded three of the parts today all in one flask. I did this to,
1. see if I could get them molded and pulled in one flask all at that same time.

2. was to see if useing larger gates would stop the shrinkage problem that the parts that I have already made and machined have.

3. and too check to see if a lower pouring temp would help.

Here are the photos.

number one shows how much shrinkage I ended up with by using a much larger gate into the part. this same part the first time I poured it shrunk in almost a quarter of and inch.


number two shows the surface finish on what was the bottom half of the mold.


number three shows the the top half of the mold, still haven't figured out why the difference in metal color from the top of the part to the bottom unless it has to do with the sand still having way too much oil in it.


DA