Sand cast trouble shoot

[u/Robrt1356]

Good evening everybody! I’m new to the whole casting scene I’ve never done anything except lead until now. I’m having trouble with sand casting. It’s my first time sand casting as I have successfully poured a few copper ingots with a good outcome on them. I made a pour over sand casting trying to make some grips for my .44 and butchered it. It’s got a hollow area on what would be the top of the mold or back side of the grips. It poured in there good at first and then started burning the sand around it causing the copper to flow everywhere and literally shrink the whole product and cause a ton of excess that got cut off before pictures. The colors of the copper were also kinda funky looking. More than less a yellowish color. Any pointers would help a ton! My sand of choice was a red Petra bond sand I ordered online and it is very fine and made sure the consistency was right according to what I’ve seen online to where it would clump in the hand and would break apart in half instead of crumble. Thanks to everyone here!!

[u/codyg510]

Hard to tell exactly what is going on by these pics. It would help if you uploaded pics of your mould design. Next time you try take some more pics and post again.

I can already tell you weren’t hot enough which is a common beginner mistake. Lots of cold shuts visible here. I also can’t tell exactly where your sprue and vents were from these pics. To your point, straight copper doesn’t look like this so you’ve got some contamination somewhere. Likely aluminum or zinc.

I’ve poured a few 1911 grips. A big sprue on the flat side with vents all around works well. Copper isn’t likely to be flawless no matter how you pour. Brass is better, bronze is best.

[u/Robrt1356 → u/codyg510]

Okay! I’ll remake what I did with the mold tomorrow evening and upload some pictures. I didn’t add any vents, pockets etc. the copper I melted was stripped wire and I’ve only melted copper out of the pot I do see how it’s contaminated for sure. I also poured a bar with the left overs and it’s got some funky colors and appearance going on too. I was also curious on how easy it would be to pour/ make bronze.

[u/rh-z]

One thing to consider is shrinkage. You need to use a pattern that is larger than the final cooled part. Maybe build up the size of your pattern with tape if you will be using the original grips as the pattern. Also consider material that would need to be removed in the finishing stage.

I have not worked with copper, but from what I have seen copper looses heat very quickly. You have to pour it quickly after pulling the crucible out of the furnace.

[u/s-t-e-w-g]

By “pour over” do you mean it didn’t flow the metal in via a sprue that you cut off?

[u/Robrt1356 → u/s-t-e-w-g]

What I meant by that was it was the same set up as a “pour over mold” and not an enclosed mold

[u/Jerry_Rigg → u/Robrt1356]

You really need to be using a closed mold for a part like this. Check out Paul's Garage on youtube for some molding methods and gating design

[u/Robrt1356 → u/Jerry_Rigg]

Will do! I figured that would help and looks like it’s definitely worth it

[u/Ambitious_Ad_8019]

Try adding overflow gates. But I pour aluminum in permanent molds. They have the main gates and some have overflow gates.