Non-Chemical Just beginning melting, what should I buy?

[joepo]

Hey All,

I'm a gold buyer in San Francisco, and I'm looking into melting my own gold instead of sending it away. I've been doing some research but you guys are all very knowledgeable so I just wanted to get any advice I can.

I will be buying equipment from airgas. I will be melting at least 5 Oz. of gold at a time but sometimes as many as 30 Oz. Mainly 60% purity (When you average out the 10k, 14k, 18k, 22k, etc.) I am also looking to melt silver jewelry and flatware. Those melts will be roughly 10 - 50 Oz. at a time. I'd like to go to my local airgas store to purchase the torch set-up. Here's a link of what they have to offer, if you guys could please be so kind to recommend one of them for me that would be great http://www.airgas.com/browse/product_list.aspx?catID=400&page=1&attribute=0:Acetylene.

I was thinking this one looked the best but have no idea. http://www.airgas.com/browse/productDetail.aspx?Category=400&product=RAD64003013

Also, if there's any additional torch tips or other accessories that you guys believe would be vital to my torch outfit I would really appreciate it.

I was going to get some crucibles from otto frei http://www.ottofrei.com/Melting-Crucibles-and-Dishes-Graphite-Fused-Silica-and-Hi-Temp-Platinum-Type-Also-Handles-and-Tongs/

Or this one looked ok http://www.ebay.com/itm/MELTING-CRUCIBLE-WITH-HANDLE-40-OZ-CUP-TYPE-CRUCIBLE-HOLDER-MELT-GOLD-SILVER-/200652101103

Thanks in advance guys

 

[element47.5]

I'm not going to address the wisdom of melting your junk jewelry. I don't know what you think it will achieve. To me, it is every bit as likely that you'll end up with an ingot of...12.3 karat gold or something weird like that, with inclusions and dirt and the net you get back from your refiner (many of whom are not real refiners but consolidators) will reflect an uncertainty that causes him to underpay you. But...you are in this business and I am not.

You are asking for spending a LOT on fuel if you use that little acetylene tank. (Known as an "MC") tank. Acetylene tanks should be chosen such that not more than 1/7th the total (rated) volume is drawn out in an hour. That is because most of the contained acetylene is dissolved in acetone which soaks a porous substance (not sure of the composition, perhaps clay or some kind of relatively inert mineral) and if you draw too much acet from the tank too fast you'll start to pull liquid acetone into your torch. Not good.

Even ignoring the prior paragraph, in my estimation you'll not be happy with that sized acet tank. Those are used primarily in air-acetylene torches used for soldering plumbing fittings together. For that they are GREAT because they blast a lot of heat into the joint quickly, which means you can get in and get out and you can tolerate a little water in the line, which will generally defeat you completely if you try to solder copper pipe with air-propane. But the point is, that acet tank is used by guys who ignite the torch, heat up the joint for 20-30 seconds, apply solder, and scoot. Thus their use is very, very intermittent and they seldom approach the 1/7th per hour threshold. That MC tank, running a torch suitable for melting the charge of gold you are talking about, would last maybe 20-30 minutes (WA guess) and maybe that's enough for you to do a few batches but the notion remains, that is not a good fit for the application. Last time I refilled an MC (last year) it was about $25. And by the way, with those baby single stage regulators and undersized tanks, you will "lose" a modest amount of your gas because as the tank empties and the internal pressures fall, the regulator will not be able to keep constant pressure as fed to the torch especially in the last 10-15% of the tank capacity. That means you will have to constantly futz with the regulator pressures as the tanks get low. Kind of like running out of hot water during a shower and you have to always turn up, up, up the hot water to keep a cozy temperature.

I believe you would better served using oxygen-propane in your torch. You should be able to search the forum for "propane" "torch" or similar to review several prior discussions we've had on the topic. To use oxy-propane, you typically buy an oxy-acet torch rig and buy 1-2-3 tips designed for propane. They (the extra tips you would need) are not very expensive. If you use oxy-acet, there is also a great chance you will vaporize miscellaneous metals within the jewelry and create more toxic fumes than I would like to have going on. In turn, those can create oxides as pollutants in your ingot.

Finally, the listed price of that little rig is very high. Victor is a very highly regarded brand but it is not the only one. The price of that rig represents premium for portability and compactness. You should be able to get a brand new oxy-acet rig for $250 without even breathing hard and your two tanks of fuel for well under $150.

 

[Findm-Keepm]

I'm not going to address the wisdom of melting your junk jewelry. I don't know what you think it will achieve. To me, it is every bit as likely that you'll end up with an ingot of...12.3 karat gold or something weird like that, with inclusions and dirt and the net you get back from your refiner (many of whom are not real refiners but consolidators) will reflect an uncertainty that causes him to underpay you. But...you are in this business and I am not.

You are asking for spending a LOT on fuel if you use that little acetylene tank. (Known as an "MC") tank. Acetylene tanks should be chosen such that not more than 1/7th the total (rated) volume is drawn out in an hour. That is because most of the contained acetylene is dissolved in acetone which soaks a porous substance (not sure of the composition, perhaps clay or some kind of relatively inert mineral) and if you draw too much acet from the tank too fast you'll start to pull liquid acetone into your torch. Not good.

Even ignoring the prior paragraph, in my estimation you'll not be happy with that sized acet tank. Those are used primarily in air-acetylene torches used for soldering plumbing fittings together. For that they are GREAT because they blast a lot of heat into the joint quickly, which means you can get in and get out and you can tolerate a little water in the line, which will generally defeat you completely if you try to solder copper pipe with air-propane. But the point is, that acet tank is used by guys who ignite the torch, heat up the joint for 20-30 seconds, apply solder, and scoot. Thus their use is very, very intermittent and they seldom approach the 1/7th per hour threshold. That MC tank, running a torch suitable for melting the charge of gold you are talking about, would last maybe 20-30 minutes (WA guess) and maybe that's enough for you to do a few batches but the notion remains, that is not a good fit for the application. Last time I refilled an MC (last year) it was about $25. And by the way, with those baby single stage regulators and undersized tanks, you will "lose" a modest amount of your gas because as the tank empties and the internal pressures fall, the regulator will not be able to keep constant pressure as fed to the torch especially in the last 10-15% of the tank capacity. That means you will have to constantly futz with the regulator pressures as the tanks get low. Kind of like running out of hot water during a shower and you have to always turn up, up, up the hot water to keep a cozy temperature.

I believe you would better served using oxygen-propane in your torch. You should be able to search the forum for "propane" "torch" or similar to review several prior discussions we've had on the topic. To use oxy-propane, you typically buy an oxy-acet torch rig and buy 1-2-3 tips designed for propane. They (the extra tips you would need) are not very expensive. If you use oxy-acet, there is also a great chance you will vaporize miscellaneous metals within the jewelry and create more toxic fumes than I would like to have going on. In turn, those can create oxides as pollutants in your ingot.

Finally, the listed price of that little rig is very high. Victor is a very highly regarded brand but it is not the only one. The price of that rig represents premium for portability and compactness. You should be able to get a brand new oxy-acet rig for $250 without even breathing hard and your two tanks of fuel for well under $150.

.....and many thanks from me - I've yet to buy a torch kit, but will certainly heed to your suggestions!

Cheers,

Brian

 

[joepo]

I'm not going to address the wisdom of melting your junk jewelry. I don't know what you think it will achieve. To me, it is every bit as likely that you'll end up with an ingot of...12.3 karat gold or something weird like that, with inclusions and dirt and the net you get back from your refiner (many of whom are not real refiners but consolidators) will reflect an uncertainty that causes him to underpay you. But...you are in this business and I am not.

You are asking for spending a LOT on fuel if you use that little acetylene tank. (Known as an "MC") tank. Acetylene tanks should be chosen such that not more than 1/7th the total (rated) volume is drawn out in an hour. That is because most of the contained acetylene is dissolved in acetone which soaks a porous substance (not sure of the composition, perhaps clay or some kind of relatively inert mineral) and if you draw too much acet from the tank too fast you'll start to pull liquid acetone into your torch. Not good.

Even ignoring the prior paragraph, in my estimation you'll not be happy with that sized acet tank. Those are used primarily in air-acetylene torches used for soldering plumbing fittings together. For that they are GREAT because they blast a lot of heat into the joint quickly, which means you can get in and get out and you can tolerate a little water in the line, which will generally defeat you completely if you try to solder copper pipe with air-propane. But the point is, that acet tank is used by guys who ignite the torch, heat up the joint for 20-30 seconds, apply solder, and scoot. Thus their use is very, very intermittent and they seldom approach the 1/7th per hour threshold. That MC tank, running a torch suitable for melting the charge of gold you are talking about, would last maybe 20-30 minutes (WA guess) and maybe that's enough for you to do a few batches but the notion remains, that is not a good fit for the application. Last time I refilled an MC (last year) it was about $25. And by the way, with those baby single stage regulators and undersized tanks, you will "lose" a modest amount of your gas because as the tank empties and the internal pressures fall, the regulator will not be able to keep constant pressure as fed to the torch especially in the last 10-15% of the tank capacity. That means you will have to constantly futz with the regulator pressures as the tanks get low. Kind of like running out of hot water during a shower and you have to always turn up, up, up the hot water to keep a cozy temperature.

I believe you would better served using oxygen-propane in your torch. You should be able to search the forum for "propane" "torch" or similar to review several prior discussions we've had on the topic. To use oxy-propane, you typically buy an oxy-acet torch rig and buy 1-2-3 tips designed for propane. They (the extra tips you would need) are not very expensive. If you use oxy-acet, there is also a great chance you will vaporize miscellaneous metals within the jewelry and create more toxic fumes than I would like to have going on. In turn, those can create oxides as pollutants in your ingot.

Finally, the listed price of that little rig is very high. Victor is a very highly regarded brand but it is not the only one. The price of that rig represents premium for portability and compactness. You should be able to get a brand new oxy-acet rig for $250 without even breathing hard and your two tanks of fuel for well under $150.

Thanks so much for helping me out.

The reason I'd like to melt my own gold is because I recently purchased an XRF and I'd like to assay my own gold before I send it out to Dillon Gage (consolidator) to see how accurate they've been treating me. Also, we've been buying gold from most of the jewelers, and other small time gold buyers in this area for quite a while, we'd like to be able to more accurately buy their stuff, and assay it for exact (almost) purity. We'd also like to expand, and start purchasing more gold, by offering higher payouts to other gold buyers and jewelers.

I'm going to shop around and try to find what a cheaper rig. Just so I understand what your saying, I should get an oxy-acet rig, and buy a propane tank and oxygen tank. Do you have any recommendation for regulators?

Thanks Again.

 

[element47.5]

Awww geez, I just found that green-tote mini welding rig at a garage sale for $50. With tanks, in test dates. No acet regulator. I am trying to see what the tanks are worth. But the welding handle/reg/ cutting head is Victor. Couple of new unused welding tips, only the cutter head is used. One of those situations where I have essentially no use for it but it is such a stupid deal I don't know if I'll be able to resist. My bro uses an MC tank for soldering plumbing fittings, but he already has one. This set probably has $15 worth of acetylene and $10 worth of oxygen in it.

Decisions....decisions.