New silver pourer struggling.

[Yardman777]

Just started pouring .999 fine silver from shot. Really seem to be struggling with getting the desired finish. My bottom surface against the mold is not smooth and the top is frosty and bubbly. I keep the torch on the mold for the entire pour. I use a furnace with graphite crucible heated up to 1100 degrees C. Can't seem to find any rhyme or reason. Any help would be appreciated. Thank you

[monkey]

Hey great to see a new silver creator starting out!

@BackyardBullion held a live stream last week where I think he was getting a similar issue? (I'm no expert so could be wrong).

The silver he poured was getting too hot due to a dodgy furnace. He was getting air pockets on the bottom of the mold. I think this was due to the silver being too hot and maybe the mold not being 100% dry of moisture.

Once he switched to a new furnace his results improved, I think he also changed the silver shot he was using and got a new graphite crucible which improved things further.

The molds seemed to be getting a dark spot on the pours where the silver was too hot, can you see any dark spot in the bottom of your molds where the silver makes first contact?

Link to vid below plays from 32mins through

 

[JamesH]

@LiquidMetalsUK @StBeesSilver may be able to offer you some advice?

[BackyardBullion]

There are so many variables to consider. Humidity of the air, temperature of the air. Temperature of the silver, try pouring at 1050 or 1025 even and see what the results are?

The silver can be a factor too, it sounds strange but I have had very different experiences with shot Vs chopped up bars and coins. 

One thing to maybe do is get a graphite stiring rod and give the molten Silver a gold mix before pouring.

Quality of the graphite mould, moisture in the mould.

Quality of the crucible.

Speed of your pouring, how fast does the silver cool?

Are you using a mapp torch, or a butane torch?

The torch might be introducing gas bubbles as the flame hits the silver, maybe move it further away or turn the power down.

So many factors, that's why I love this so much and it's always a challenge.

I am also a big believer in attitude of the pourer. I know physically it can't make much difference but if you are not in the right mindset it can often be a bad day.

[StBeesSilver]

As well as all those things that BYB has mentioned I'm sure there is carbon dioxide produced by the graphite when heated above a certain temp. This can really affect the bottom side to the point large bubbles can form underneath. You've to find a way of controlling the heat and amount of oxygen that the heated mould can react with to form this co2. Then you've to find a way of cooling the silver and mould at an even rate without introducing oxygen to mix again. If oxygen gets at it before they've cooled enough you get what looks like a cauliflower grow out of the silver. I believe this caused by that oxygen if it gets in there.

I'm sure that perfectly cast bars are done in some sort of vacuum or controlled environment. 

Lots to think about. 

[HonestMoneyGoldSilver]

2 hours ago, Yardman777 said:

999 fine silver shot

 

When in Kentucky: