# Better than MAPP ?



## Noxx (Mar 8, 2007)

Hello,
Few hours ago, I went to Canadian Tire and I saw a bottle of Brazing Fuel. It is Propylene. Is it better than MAPP ? The flame can reach 3600°F (1980°C)
The bottle cost 1$ less than Stabilised MetylAcetylene Propadylene (don't know how to write it correctly sorry)
Also, if I use this gaz, can it brokes my crucible ?
Thanks


----------



## lazersteve (Mar 8, 2007)

Noxx,

The stuff is not as hot as MAPP 2210°C (combined with Oxygen its 2927°C ). The temp sounds good enough to melt gold though and so does the price. The cupels are made of a variety of substances from bone ash to magnesite. The bone ash ones are very delicate and won't handle really high temps for long. The magnesite ones are more durable and can take the heat better. There are several other types of cupel materials so its really hard to say yes or no. 

Steve


----------



## jmelson (Mar 9, 2007)

Noxx said:


> Hello,
> Few hours ago, I went to Canadian Tire and I saw a bottle of Brazing Fuel. It is Propylene. Is it better than MAPP ? The flame can reach 3600°F (1980°C)
> The bottle cost 1$ less than Stabilised MetylAcetylene Propadylene (don't know how to write it correctly sorry)
> Also, if I use this gaz, can it brokes my crucible ?
> Thanks


According to my local welding/gas distributor Cee Kay, their Propylene is IDENTICA:L to MAPP, but that is a name trademarked by Dow, and they can't use the trademark. MAPP is MethylAcetylene, Propadiene and Propane. So, everybody else just calls it propylene as a generic trade name.

I can assure you you can smelt gold with MAPP/Oxygen, and you can burn up your crucibles. If you are using thin ceramic crucibles, uneven heating will break them. These are not the crucibles for metal smelting. What you want are much thicker crucibles that are made for precious metal smelting. There are also cupels that are used to absorb the base metal/flux residue for the final stage of smelting. These are VERY thick and shallow.

My crucibles mostly burn up due to too much left-over zinc from things going wrong with the precipitation step.


----------



## Noxx (Mar 9, 2007)

So if I buy a Mapp/Oxy torch, should I buy a Graphite Mold or it will oxidise ? (I know it oxidise at 800°)
Thanks


----------



## jmelson (Mar 10, 2007)

Noxx said:


> So if I buy a Mapp/Oxy torch, should I buy a Graphite Mold or it will oxidise ? (I know it oxidise at 800°)
> Thanks


It may oxidize slightly. But, you don't put the torch to the mold, you heat the gold in a crucible (or cupel) and then pour it while still molten into the mold. Once the gold is in the mold, air can't get to the part covered by gold, so the only oxidation (burning, really) could be right at the edge. That will stop pretty quickly as the gold cools.


----------



## Noxx (Mar 10, 2007)

Ok ! But I'm not able to pour gold with MAPP. Gold solidifies intantly when I move it...


----------



## lazersteve (Mar 10, 2007)

Noxx,

I have a 1 oz. graphite mold that gave me all kinds of trouble. The darn thing is such a good heat asorber that when I pour the molten gold into it the gold 'freezes' so quickly that it forms a pile instead of forming to the mold. I've tried heating the heck out of the gold before pouring and it never worked right for me. I did get results when I turned the mold sideways, cut out one of the four sides, clamped it to a piece of steel and poured the gold into the slot formed from the top. This formed a very ugly bar that was thin an flexible. At this point I went exclusively to the rod mold.

Steve


----------



## Noxx (Mar 10, 2007)

Ok I see... 
Maybe I should consider buying a steel ingot mold. Is it possible to make 1/2 oz. flat gold bars (shining)?


----------



## lazersteve (Mar 10, 2007)

Noxx,

I haven't seen any steel molds like that. I'll do some searching and get back to you.

Steve


----------



## Noxx (Mar 10, 2007)

I was looking on ebay and I came to this:
http://www.ganoksin.com/borisat/nenam/granulation-gold.htm
It shows how to make an ingot mold with a charcoal block. I just tried melting gold on charcoal (not a compressed block, only wood charcoal) and it melts really quick. Charcoal reflects heat I think.


----------



## lazersteve (Mar 10, 2007)

This is very interesting. I'm going to try this technique using 24kt. Maybe Harold knows more about this kind of thing?


Steve


----------



## Harold_V (Mar 10, 2007)

Noxx said:


> Ok I see...
> Maybe I should consider buying a steel ingot mold. Is it possible to make 1/2 oz. flat gold bars (shining)?



Steel is not a good choice for molds for precious metals. If you want a metallic mold, it should be machined from cast gray iron. Even that can spell trouble with soldering. Molds should be well blackened with a sooty acetylene torch, then preheated just under the point where the soot burns off for the best results. Also, in order to avoid the characteristic pipe that forms as pure gold cools, a torch should be played on the surface of the gold so it cools slowly, allowing the entire ingot to shrink uniformly. Otherwise you get a deep dimple. 

By the way, gold that pours without that feature isn't very pure. Nor is gold that has a frosty appearance. 

Gold isn't fond of pouring in thin sections. If you try for a small ingot in a large mold, the gold will ball up and not fill the entire mold. The ½ ounce ingots I used to cast were poured in a very small mold in order to get them to resemble a tiny loaf of bread. Half a troy ounce of gold poured into a 1 ounce mold wouldn't fill the mold bottom. 

If I haven't made mention, I am a retired tool maker/machinist. I used to make my molds, which was a definite advantage. 

Harold


----------



## lazersteve (Mar 10, 2007)

Harold,

Thank you for the informative post. I have been struggling with several of the above mentioned problems and you have helped me understand why. I will be asking more questions of you concernig molding techniques when 
Another problem I've had with my rod mold is that the gold will sometimes 'fountain' out of the mold once poured. I thought this might be due to air being trapped under the gold as the mold is poured. When the gold fills the mold the air gets very hot and forces the molten gold out the top of the rod mold. Can you help me understand why this is? 

Thank you again,

Steve


----------



## Harold_V (Mar 11, 2007)

Aside from a tiny anode mold I made that poured roughly 5 ounce gold anodes (for a gold parting cell I never completed), I never poured anything that was configured like your gold items. Such molds usually have tiny bleed lines cut from the cavity to allow air and gasses to escape, and yours may not be open. It's also possible you are producing CO2 by some means, and it's forcing the gold out. Also, don't discount the slight possibility you're creating a tiny amount of steam. If you're pouring your gold into a cold mold, that's likely what's happening. I suggest the mold be heated to a temperature greater than the boiling point of water-----and if you do it with your torch, avoid playing it in the cavity. If the mold isn't heated well, you will have introduced water via the torch. It might be interesting to hear what you determine is the problem, Steve. 

Harold


----------



## tarvus (Mar 27, 2007)

lazersteve said:


> Noxx,
> 
> I have a 1 oz. graphite mold that gave me all kinds of trouble. The darn thing is such a good heat asorber that when I pour the molten gold into it the gold 'freezes' so quickly that it forms a pile instead of forming to the mold. I've tried heating the heck out of the gold before pouring and it never worked right for me. I did get results when I turned the mold sideways, cut out one of the four sides, clamped it to a piece of steel and poured the gold into the slot formed from the top. This formed a very ugly bar that was thin an flexible. At this point I went exclusively to the rod mold.
> 
> Steve



Steve, I have a mold exactly like the one you use for your round rods and also a one ounce graphite mold. I have had much better success with the graphite mold. Here are a few tips that might help you when you use it:

#1. Use a 50 dwt burno crucible to do your melt. The reason for this is that this size and style crucible almost EXACTLY covers the graphite ingot mold. When you melt your gold, keep the crucible on top of the mold. This will pre-heat it nicely and assist in your pour. The burno crucible has a convenient little pouring spout too which makes it easier to pour.

#2. Though the ingot mold says it is one ounce, I find it works best with about 60 to 70 grams of gold (roughly two ounces). The larger amount of gold provides greater thermal mass and will stay liquid longer than a smaller amount. Don't worry, it won't overfill the one ounce mold.

#3. Use a large pair of channel locks rather than those flimsy burno crucible tongs when doing your pour. I use a regular Mapp gas torch which gets plenty hot enough for the melt and the pour.

#4. Just before doing the pour, slightly tilt the crucible so the gold pools right at the edge of the crucible lip. I hold the channel locks in my right hand and the Mapp torch in my left. I rest the bottom of the crucible lip right in the middle of the hole in the mold - touching the graphite. This enables me to play the torch from the gold puddle to the lip of the crucible to the graphite mold thus heating the mold even further, pre-heating the pouring lip so the gold will not congeal there during the pour, and it keeps the gold hot and ready to go. If you hold it at the right angle, the little borax beads will be blown together by the torch forming a single large bead.

#5. Pour rapidly into the middle on the indentation in the mold while keeping the torch flame on the resulting ingot. This seems to make for a smoother, cleaner appearance. The ingot will solidify within seconds - even with the torch flame on it. When it does, immediately grap the mold with your channel locks and dump the ingot into a container of water to quench it. If done very quickly the thermal shock will break off and borax flux beads. 

I'll try and take some photos to post of some of the resulting ingots I've made.

regards!
Tarvus


----------



## lazersteve (Mar 27, 2007)

Tarvus,

Thanks for the tips. As I previously stated I've cut one side out of my graphite mold so I'll have to fashion another before I can try your suggestions. I really like the post Noxx made with the website reference to the guy who demonstrates using the graphite molds for casting anodes.

The other side effect of the graphite mold is the way the torch causes it to roughen with use. This gives the surface of the mold a porus appearance.

Keep the great info coming,

Steve


----------



## Rockman (Nov 7, 2012)

New guy here. I tried pouring some gold into 1 grain square graphite molds and just would not work. I have ordered a 1 gram round graphite mold to try making 1 gram round gold shot. I am wanting to make either 1 grain or 5 grain bars either round or square. Does someone sell a press that you can pour your gold when melted into a press and then press your final gold into a defined size and weight such as 1 grain, 5 grain, or 1 gram, 5 gram?


----------



## etack (Nov 7, 2012)

why do you keep asking to pour one GRAIN rounds? You can't pour them, they are stamped. have you held a grain of gold? If you plan to sell them on ebay as a way to mislead people than you won't get much help here.

you will also not successfully pour a 1g round it will look like a button. 

may karma be with you

Eric


----------



## Rockman (Nov 7, 2012)

I am not trying to sell anything on ebay. Just wanting to make small amounts of gold to sell in lower dollar amounts that anyone can afford to start in gold purchasing. If you know of a press or stamp that can make smaller bars or rounds in sizes less than 1 ounce I would appreciate the information.


----------



## butcher (Nov 7, 2012)

jewelry supply houses like Lacy West should have what you are looking for.
http://www.lacywest.com


----------



## jimdoc (Nov 7, 2012)

Rockman said:


> I am not trying to sell anything on ebay. Just wanting to make small amounts of gold to sell in lower dollar amounts that anyone can afford to start in gold purchasing. If you know of a press or stamp that can make smaller bars or rounds in sizes less than 1 ounce I would appreciate the information.




Why not just sell shot priced by the grain? That would give people the choice of what size piece they get, and you would probably sell more. Small bars are pretty much useless anyway.

Jim


----------



## etack (Nov 7, 2012)

you can buy gold sheets and cut it up.


Eric


----------



## Geo (Nov 7, 2012)

when coins were first being struck, the gold was weighed and then formed. stamped by hand with a die and hammer.you can have a machine company make a three piece die and stamp your own rounds. with no design, it shouldnt be too expensive. you can recoup the cost from selling one gram or one grain rounds for 100% over spot price. people are stupid when it comes to gold and if you have no scruples you should do well.


----------



## Geo (Nov 7, 2012)

heres a thought, buy 24K gold wire which will make it easy to cut and weigh.


----------

