Smelting problem

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Chirou

Active member
Joined
Jun 13, 2018
Messages
38
Hello newbie here, i got myself some butane torches they shoult get up to 1300 degrees celcius and melt my gold powder but it seems they don't get that high temperature. Anybody know what can i do to increase temperature? Already spent a lot of money for those and now i'm trying to figure out how to make them reach that temperature. Maybe building up a little furnace or something and then using butane torch will work? After few different tries i'm out of ideas what to do it looks like some gold smelted but it refuses to smelt corectly and join into one bead it more resembles some little nuggets.
 
The problem with failure to melt gold is often heat loss. Insulate the melting dish and it will work a lot better. The size of the torch would also matter, it's not only the temperature that decides if you can melt something.

Maybe you should show a picture of the melting dish and torch you are using. As well as your setup, that would make it easier to help you.

Göran
 
i will have to go to my garage to make one, but the torch i'm using is simple butane torch like shown on few YT videos, could there also be a possibility that i added too less of the flux ? i got myself stuff like that posted below. i will have night shifts in 2 days maybe i'll build something like a little furnace isolate it with some clay etc and try again. The worse scenario i will just have to buy better torch. I also tried using 2 torches, everything was glowing red, some of gold lets say melted a bit cause it came together in few limps and flux was bubbling a bit but still i don't think it was enoght. Or maybe really i added to less flux (as flux i use Baking soda + borax)
 

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Chirou said:
I also tried using 2 torches, everything was glowing red, some of gold lets say melted a bit cause it came together in few limps and flux was bubbling a bit but still i don't think it was enoght.
You need to get beyond red. See Furnace Temperature Colors.

As Göran said, the problem is usually heat loss. Your graphite dish conducts heat really well, so it will lose heat as fast as you can pour it on with your torch(es).

Dave
 
One way to make melting easier is to put up a reflecting surface. Heat radiating out is reflected by surfaces so a small cave of firebricks makes it a lot easier to melt. Check this thread for an idea of what I'm talking about.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=61&t=19840
I pushed the melting dish inside the cave and the gold melted very easy. The torch used LPG (gasol in Swedish) with air.

Another good way to ease melting is to get some fireproof insulation and put the melting dish in it. That will minimize the heat loss through the bottom of the melting dish.

Melting is like filling a leaky bucket, the level (temperature) is rising when you pour water (heat) into the bucket, but as soon as you turn off the water supply the water drains out.
The more water you have in the bucket the more it leaks until you end up with a steady state and as much water leaks out as you pour in. To get a higher level you can either pour more water in (getting a better torch) or plug the holes (insulate, reflect the heat).

Göran
 
g_axelsson said:
Melting is like filling a leaky bucket, the level (temperature) is rising when you pour water (heat) into the bucket, but as soon as you turn off the water supply the water drains out.
The more water you have in the bucket the more it leaks until you end up with a steady state and as much water leaks out as you pour in. To get a higher level you can either pour more water in (getting a better torch) or plug the holes (insulate, reflect the heat)
.


Göran

Excellent analogy.

The torch you are using is a culinary torch. Normally, they are used to add finishing cosmetic touches to already cooked desserts or meats.

Using Goran's analogy, the "hose" you are using is too small to add enough "water" to overcome the "leak" in your bucket. The fuel source for these types of type of torches is usually butane.

Patch your "leaks" as much as possible but still get a larger "hose" and better (hotter) fuel source. The transfer rate of your fuel is also important.

James
 
Actually it's almost the same thing, it's even called "heat flow" and it can be described physically by the same formulas. Just separate a few constants and the name of a few variables.

Heat flows from a hotter spot to a cooler spot through a solid object the same way as water flows from a higher point to a lower point through a tube.

... if we ignore convection of gases or liquids which can move heat a lot faster and in a very non-linear way. :mrgreen: But that is to go into finer details than necessary.

Göran
 
Use some plasterboard or gyproc as they call it in the US. Also buy mapp gas. Messing about with butane isn't getting you anywhere fast.
 
Thank you guys, i will try to make some insulation, i have to check how hard and how expencive it will be to get mapp gas torch in here. As far as i see now it's not even on the internet Polish sites theres only gas but it's very expencive more expencive than all chemicals etc. Thats why i really hoped to get it working with Butane torch as someone showed on YT cause it's easy to get here.

But theres a chance to get LPG gas here with a torch will this be alright ? It says 1850degrees so it seems fine but it's better to ask you guys ^^ .
 
anachronism said:
Use some plasterboard or gyproc as they call it in the US. Also buy mapp gas. Messing about with butane isn't getting you anywhere fast.

MAPP is a trademark name https://en.wikipedia.org/wiki/MAPP_gas and is no longer available here in North America. It has been replaced by MAPP Pro. Original MAPP had some propane in its mixture. MAPP Pro has the propane substituted with propylene. MAPP Pro doesn't have the "kick" (BTU) that MAPP had.

James
 
Chirou said:
Thank you guys, i will try to make some insulation, i have to check how hard and how expencive it will be to get mapp gas torch in here. As far as i see now it's not even on the internet Polish sites theres only gas but it's very expencive more expencive than all chemicals etc. That's why i really hoped to get it working with Butane torch as someone showed on YT cause it's easy to get here.

But theres a chance to get LPG gas here with a torch will this be alright ? It says 1850degrees so it seems fine but it's better to ask you guys ^^ .

Check into an Oxy/Propane set-up. Harris http://www.harrisproductsgroup.com/en/Products/Equipment/Torches.aspx and ESAB (Victor) https://www.esabna.com/us/en/products/brands/victor/index.cfm make great rosebud torches specifically designed for propane use. Do not try to use a regular oxy/acetylene rosebud with propane - it won't work well.

Unless you have built a good "oven" to trap your heat, propane by itself takes too long to do the job. It (propane) needs an assist from either injected air or oxygen to work efficiently (faster).

Peace,
James
 
Tools always cost money and good tools cost more money. Gold is worth US$40 per gram so it's worth investing in good tools when you are working with it.

Buying a couple of kitchen torches may seem a bit cheaper, but if they don't work then it is just money wasted that could have been put towards a good setup.

See if you can find a BernzOmatic TS8000 kit in your country, it does the business.
 
Well i found one seller with BernzOmatic TS8000 but it's hard to get fuel here + it costs like 1/4 of my paycheck without fuel and delivery. But it's really easy to get LPG here cause we use it in cars and if it could work it would be great, and LPG burner it's not cheap but affordable. And Oxy-Propane torches are similar price as LPG but oxy-propane set it's like half of my month earnings not mentioning that i'm spending a lot more then just half on just taxes and food.
LPG is easy to get here almos everywhere. It gives 1200celcius - 1850celcius. And i guess now it's my only hope but it would be great if someone could confirm that it will work.
This BenzOmatic TS8000 as i see in USA costs around 48dolars and here it should cost around 200-250zł and it does cost 489zł. I found Propan-Butan(LPG) welding Torch here which is not easy but not really hard to get,

I'll attach what i found available from torches. Maybe theres a chance
Great thing is that i get scraps for free and that i found HCl and HNO3 seller (which are hard to get especially HNO3 because of UE). The only step i got left is smelting but it turns out it would be a hell easier in USA or other country :(.
 

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Check this out, with the top toarch it will allow you to melt your gold. Pay particular attention to Lasersteves input, as his design is the oldest version I know of.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=7387&hilit=mini+furnace
 
I had the same problem for a long time, and have finally broken through with a set up that works for me. I built a small smelting furnace using six soft 1" thick white furnace bricks I bought on Ebay, with free delivery for like $28.00 (I think), a handmade propane forge blowtorch tip for $50.00 or so (others go for $60-100), a high pressure regulator ($20 I think), a large almost full BBQ propane tank I found off a free BBQ ($0.00), some stainless steel mesh from a salvaged outdoor heating lamp ($0.00), and miscellaneous scrap steel pieces ($0.00).
I was sure in for a surprise when I first thought a propane torch would do fine. I now also have a Mapp gas set up with the t-8000 Bernzomatic tip. I'd love to have an oxy acetylene kit too, like Sreetips uses, but I haven't found an affordable one yet. You have to keep looking and unfortunately shell out some dough. I found the small forge I made helps keep the heat in a smaller area, where it doesn't escape so quickly. I also have an entry level mig welder that I used to clad my forge in scrap sheet metal (from computers), so that it doesn't crumble. This was my fourth attempt at a forge I think. It takes what it takes.

Here are some pictures. The forge looks a bit rough but it's solid. My welding skills are only adequate, and the black paint and extra refractory cement I put on surfaces peeled off in the heat. That refractory cement doesn't seem to work very well in my experience.
 

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If you are going to build a furnace using gas then try and create a swirl furnace, a round metal container with the flame entering near the bottom at an angle to make the flame circle round it, you need to add insulation to the inside and a lid with a vent hole will help with the speed of melting and retaining the heat.
 
nickton said:
. . . . .
Here are some pictures. The forge looks a bit rough but it's solid. My welding skills are only adequate, and the black paint and extra refractory cement I put on surfaces peeled off in the heat. That refractory cement doesn't seem to work very well in my experience.

Not trying to beat you up, but, its a furnace not a forge. :D

Forge -
"A forge is a type of hearth used for heating metals, or the workplace (smithy) where such a hearth is located. The forge is used by the smith to heat a piece of metal to a temperature where it becomes easier to shape by forging, or to the point where work hardening no longer occurs."
https://en.wikipedia.org/wiki/Forge

Furance -
"A furnace is a device used for high-temperature heating. The name derives from the Latin word Fornax, which means oven. The heat energy to fuel a furnace may be supplied directly by fuel combustion, by electricity such as the electric arc furnace, or through induction heating in induction furnaces."
https://en.wikipedia.org/wiki/Furnace

Peace,
James
 
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