How do you make your silver look professional?

[Gwar]

Hello, I was pondering the different styles of making silver bars / rounds look more professional when completed, are there any tips or methods members use and would like to share ?

 

[campbellj46]

I assume you're talking about molds for bars? I use an induction furnace, the metal is melted and cooled in the same mold using a step down process. Cooling/step down 200 degrees per cycle until it reaches 600 degrees. After it reaches 600 degrees, I dump it in water for the final cooling. I still don't get a mirror, smooth finish but the finish is a 1000Xs better than poured metal.

How the major manufacturers make their bars is the same melting and cooling process.

After the melt and cooling, they are put through a roller, flattened out to size. The rolled sheets are then sheered into blanks, the blanks are stamped in a hydraulic press with the markings/design of the final product.

 

[campbellj46]

Sorry, forgot the pics. I go by the "pics or it didn't happen" philosophy


I use my dremel buffing wheel and a polishing compound to polish my bars. I did a quick polish run to show what the dremel does. It does leave streaks and i still haven't perfected the mirrored finish... yet. A sanding/buffing setup removes too much material.

 

[campbellj46]

A close up of the finish after melting and cooling. I don't know if I need a "smoother" crucible mold to melt the metal, but this is the best finish I have been able to achieve, so far.

 

[Hartbar]

Good job, what’s original material you use?

 

[Lou]

Looks like dissolved gas coming out of solution. Weird as crystal is usually the lowest O you can go!

 

[KEBinAZ]

I'm new to this blog but have experienced in smelting. I recommend you use an extra torch pointed inside your mold to remove as much oxygen as possible. Oxygen is what causes the dulling appearance. No oxygen, no dull look. At least has proven successful for me.

 

[Gwar]

Thanks for the replies, cambellj46, I have investigated the induction furnace method, but it seems rather expensive, the ones I looked at were in the many thousands of dollars range, are there better rigs that use this technology with a lower price tag? I use a wet sanding process with two different fine grit (I do lose a few grams per bar) and then I place them in a tumbler drum with polishing compound / blue aggregate, I suppose I could rework this one for a cleaner look

 

[rickbb]

I use the 2 torch method, one on the mold to pre-heat it and to keep the pour under flame, (no O), and the other on the melt as it pours. Makes pretty bars, not professional mirror smooth, but like campbell pointed out the pros mechanically roll and stamp theirs.

 

[Gwar]

rickbb, I shall try that method soon, it's just the matter of vise configuration to hold the MAP gas while pouring.

 

[campbellj46]

Good job, what’s original material you use?

The original material started as sterling silver, processed it with nitric acid, then turned it into cement silver, then shot for the silver cell, turned it into silver crystal, then this 10 ozt bar.

Edited because i forgot to add details

Thanks for the replies, cambellj46, I have investigated the induction furnace method, but it seems rather expensive, the ones I looked at were in the many thousands of dollars range, are there better rigs that use this technology with a lower price tag? I use a wet sanding process with two different fine grit (I do lose a few grams per bar) and then I place them in a tumbler drum with polishing compound / blue aggregate, I suppose I could rework this one for a cleaner lookView attachment 49556

I got my induction furnace at an auction, A glass company went out of business and I was the only bidder for it. I paid $750, I don't think anyone else at the auction knew what it was.

 

[campbellj46]

@Gwar , I might try a tumbler to see how it comes out, instead of using the dremel and polishing compound.

 

[Lightspeed]

Going back a few years to when i first started a bit of silver refining, i tried a few bars, sort of playing and feeling my way around my home made furnace, burner, graphite molds etc, i tried a in furnace melt in the Graphite mold just to see what sort of finish i could get because every time i poured a bar i got these annoying blue irridescent crystal patterns i just could not get rid of, so i tried something different. I have to confess though, i felt open flames were unkind to Graphite molds.

The end result was interesting, although my furnace is open flame LPG/Air burner, the silver was molten i decided to get it pretty warm to see the effect and try to get a better finish on the back of the bar, lol the effect was silver jumping around inside the mold as it cooled, i let the melt get too hot and the silver was now expressing absorbed oxygen, the most suprising factor was when the the bar began to skin a squiggly worm grew from the centre of the mold around 1.5 inches above the bar surface as oxygen was escaping it grew the most weirdest thing i had seen, i did kind of scare me a little as i realised the capacity for silver to take in so much air and expel it like that, got me thinking about the dangers of molten metal incidents.

So the top was ruined from that respect, but of note that the bars reverse side was the neatest i had ever made, perfectly reproducing the mold cavity with none of the associated feature usually seen on hand pours from offgassing in an open air, non temp controlled environment.

I really like your efforts @campbellj46, one day and a few more kilos of silver processed down the road somewhere i might see about an induction set up, i really like your results.

@Gwar i have thought seriously about utilising my Jewellery rolling mill, i had an idea about extruding bars into a steel mold for small pendant ingots. Just a thought, action may be a fair way off but in practice it seems sound.

Anyway, nice efforts, great results!!!

 

[Gwar]

I have thought of a few things to try, just like you, I am planning on using a s gas furnace and enclosing the graphite mold with a graphite top, I have also thought of a special build induction coil, and using a better electric type of graphite that can take the heat but still perform as a mold, there is a name for the graphite, it is in my notes somewhere..

 

[AMS-Pro]

Hey Gwar, how have you been?
I see that your silver setup is finally working pretty good, and consistently. Great job.

Have you thought about building an induction furnace, this would offset the cost.

 

[Gwar]

Hello AMS-Pro, all has been well, I had a minor setback, the new furnace broke, again.. Just by luck my neighbor builds propane fed crucible's and he is crafting one now, I have been busy at work, so the progress has halted a bit, back up and running again soon I hope, Take care, G

 

[AMS-Pro]

Hello AMS-Pro, all has been well, I had a minor setback, the new furnace broke, again.. Just by luck my neighbor builds propane fed crucible's and he is crafting one now, I have been busy at work, so the progress has halted a bit, back up and running again soon I hope, Take care, G

Again? I apologize I missed the second one. I would've given another eulogy, you have my sympathies.

I remember you saying something about your neighbor building them, third try is a charm.

Well, I look forward to seeing more progress when you get back up and running. I took a look at some of the numbers you had posted, I'm glad to see that you had gotten them close to the bottom end of the range, where it should be, and able to run consistently. Now you can scale up.

As far as if you decide to build your own induction furnace, I can help you with that too. Whenever I get moved and unpacked, I'll dig out my electromagnetic charger so you can see what it looks like.

 

[Michael4891]

A close up of the finish after melting and cooling. I don't know if I need a "smoother" crucible mold to melt the metal, but this is the best finish I have been able to achieve, so far.
View attachment 49538

that finish looks really good I have not been able to come even close to that yeti seem to be overheating or not cooling properly. I also think I need to stop adding the borax powder to me it makes it worse it sticks to the silver making it harder to clean off the bars. someone told me to add a little borax powder to your malt but I personally thought borax was just to remove the so called crap from the medal any types of impurities bust If the coins or coins I am melting to make my own bar doesn't have any impurities is the borax necessary to use and also I was told I very high heat tolerant oil or lubricant in the mold can help with keeping the poor smooth and shiny but most I have tried so far set fire and leave black and colored materiel into your poor again making it really hard to polish out of the silver.

 

[Yggdrasil]

that finish looks really good I have not been able to come even close to that yeti seem to be overheating or not cooling properly. I also think I need to stop adding the borax powder to me it makes it worse it sticks to the silver making it harder to clean off the bars. someone told me to add a little borax powder to your malt but I personally thought borax was just to remove the so called crap from the medal any types of impurities bust If the coins or coins I am melting to make my own bar doesn't have any impurities is the borax necessary to use and also I was told I very high heat tolerant oil or lubricant in the mold can help with keeping the poor smooth and shiny but most I have tried so far set fire and leave black and colored materiel into your poor again making it really hard to polish out of the silver.

Welcome.
Try to make sentences with commas, periods and line spaces.
This is really hard to read.

How do you melt it?
Gas or electric?
The mold can be dressed with oil or even better soot.

How do you pour it?
Molten Silver really love Oxygen and will soak up Oxygen from the air, which will be ejected as it solidify.

Why are you melting coins?

They have a set value and as soon they are melted, the value of the bar is just what someone are willing to pay.
Sometimes much less than metal content.