Foundry practice

[Powder keg]

I've been trying to get my foundry operation up to the point where I can melt brass and bronze's. I do a lot of practice stuff in the form of trinkets and gifts for christmass. This year I'm planning on keychains with the family name on them. One of the trinkets that I have  recently worked on is called a horeshoe. They were rumered to have been used in brothles of the wild west to let customers hnow if a room was occupied of not. I carved this pattern from a picture that I had of one. I've included a powder can for size comparason.



I was trying out my new burner and I started with aluminum. I had half a pot melted in about 15 min. My little bottle started to freeze up again and I tried running a garden hose over it. It unfroze imediatly and started running good again. Here is the result from the first pore. There was a small flaw near the top for somereason?



As soon as I was done with the aluminum, I added another crucible that I had to the furnace filled with brass and I went back into my garage/art studio and started ramming sand for another pore. It probably took me 20 minutes to ram up 2 patterns. When I went out to see if my brass was hot enough yet, I was very suprized. All the brass was melted. in fact I think it was to hot? the zinc was flarring off and it was hard to see the melt. I scraped the dross off the top and pored my brass. Here is the result.



It looks like I need to be carefull not to get things to hot now. There were a couple of porosity holes on the surface on this one. I had a hard time seeing where I was poring and I started and stopped a couple times. I think this caused it? It also might have been caused by my brass no being clean?

I'll post some pictures of my burner here later today. It worked very good. Also that regulator I have goes up to 35 Psi.

[GGaskill]

The dimple in the Al one looks like a shrinkage defect.  Where did the sprue enter?

Also, what kind of sand are you using?  The greater heat of the brass may be causing gassing from the sand.

[Powder keg]

I'm using Petrobond sand. The sprue entered on the side without the leg. Here is a picture of the casting with the sprue, gate, and vent still attached. That dimple showed up in a weird spot I thought? There was a small shrink on the back side also. but it's over the leg. I need to thin the pattern in the back so the thickness is the same overall. I like doing these trinkets for all the experence in casting that I get. 




The brass is stained black is from the oil I think? It comes off with a wire brush fairly easily.

 GGaskill, When you pored brass was there much flare up of the zinc? I've never been around anyone thats done it or seen it done. My new tongs work great, by the way:O)

The pattern was carved out of Popular. I wanted to use birch, but I couldnt find any around here. It carved nice. There wern't the hard and soft rings like that show up with pine.

Wes

[GGaskill]

I have never cast any brass; we used silicon bronze in the art foundry and the copper burns out before the silicon.  Losing the zinc is typical if you overheat.  Try to pour as soon as you reach temperature.

When making a tin bronze casting, the copper is melted by itself and the tin added at the last minute to avoid losing the tin.

Some reason you don't put the sprue at top center and a vent at each end?

[Powder keg]

The only reason for the sprue placement was I don't have any medium sized flasks yet. The pattern only had 3/4" clearance on each side, and the funnel on the sprue was very near the side of the flask.

Wes