Risering help

[HT1]

I was casting the two parts for the master pattern of this project, I also cast a piece to see if I had the gating and risering perfect before I put it all on a matchplate. my risering technique was not perfect, I did not well the riser bases, so I probably did not get optimal feeding. looking for some suggestions

First off the part is about 1.75 in Diameter, the base is 3 X 2 X 1.375. the base had a 2 inch riser, and seems perfect. I poured Aluminium at 750C the rocket had a 1 inch riser



The risers did not seem to feed very much, as I mentioned I suspect they froze off early because I did not add a basin to them





See no basins in the drag



at this transition between the top and the base, you can see a "shrinkage defect?", it is very small but almost entirely in the drag



The cope of the rocket, is just a little bit flat, I'm sure it has internal shrinkage. I cannot use a larger riser on the rocket without moving up to a larger flask

Do you all think adding the basins to the risers will be enough to get me by, should I enlarge the fillet between the rocket and the stand, or will that make things worse?

any other advice?


V/r HT1

[Jammer]

The shrinkage area at the connection of the top and base... could that be more a rounded corner so there would be less chance of a hot tear?
The part looks good to me but I'm still learning. I just got a book from Kaiser Aluminum and am reading about diferent alloys and risering. If I come across something, I'll let you know.

[Jammer]

Ok, in the book it suggests a chill be placed in between two heavy sections like you have, especially close to the area where the tear occurs. Other point on shrinkage cracks, increase fillet radii and provide better feeding with larger or more risers close to the defect area.

[Harry]

Did you get this sorted HT? Looks to me like if you moved the bob for the rocket nose over towards the other bob a little you could go much larger with it and that what you need I am fairly certain. The rocket is larger than the bob so the one that is there is not doing anything at all since it is surely freezing first. For me the first thing I do is make larger feeds and shrinks if I have any trouble at all.

Also having little or no feeding from a bob in an aluminum piece isnt odd at all when you are using a good alloy.

[HT1]

yes, it worked out, I had to make the piece joining the rocket and the base larger, it was mostly a tear, caused by the two pieces shrinking away from each other

[Harry]

Good to hear and even better to see you back on the pouring shank. Before I took my hiatus you took one yourself and I thought you sounded like you might not be picking it back up with the same fever. You have a load of talent and knowledge and it would be a shame to not put it to use.

[HT1]

Actually I'm currently seperated geographically from my tools. I took a rather long break not from the foundry, but rather from the computer. I come to believe that people where less then willing to listen to my advice, so I simply stopped sharing

[Jammer]

I'm always eager to read your posts, I don't comment on things as much as I used to, tends to turn into BLAH BALH BLAH. You do great work and I have bookmarked your plaque thread. Thanks for all your pointers.

[Harry]

I'm with Jammer on that.

I know what you mean though and sometimes get that feeling myself. Either from always getting "well you could have done it this way" or from a seeming text swallowing black hole where no reads.

Either way I try to look at it in the case of the former that we all have our own ways of doing things. Something are just more comfortable for us personally and achieve the same ends. In the latter where a post may not illicit any response I just think about the many people who have read it and may take something away from it big or small. Lost of people dont like to participate much but are avid readers. Seems most of the time there are quite a few guests reading here which is fine. I wouldnt want to exclude anyone just because they dont want to post.

[Rasper]

Keep posting HT1. I read all of your posts. I don't do sand casting so I don't have much to ask or to offer in that field, but still, I learn a lot from you.

Richard