# Aluminium Sampling Furnace



## scrapdealer

Just a few pics of a gas fired aluminium sampling furnace and accessories we just built.
Furnace is completely lined using 1300C castable refractory, lift out crucible is 5kg aluminium capacity, gas burner purchased locally.
The mushroom sample mould is for casting samples which are machined on the face and analysed on a spectrometer for various elements.
Ingot moulds from 4" x 2" channel.


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## Harold_V

I've built my share of such furnaces. Very nice job you've done! I'm impressed. 

Harold


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## scrapdealer

Thanks Harold.
It is just a toy for me really.. normally the furnaces I have built and operated in the past are 5 - 10 ton rotary's and 5 - 20 ton reverb's.


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## butcher

that really is nice, well done, do you have any information on your burner,I really like the hinge, and that is a nice mold.


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## scrapdealer

Some pics of the burner as requested. We get them here locally from the machinery sundries supplier, cost around US$ 40.00. Easier and most probably cheaper than making a gas burner. They are very good and soon get up to the operating/melting temp in the small furnace. 
However I suspect with the name "Alibaba" they are most probably made in China (or perhaps India...!).
I have used a bank of 4 in the past for pre-heating ingot moulds on a 180 mould rotating casting conveyor without any problem.

http://i440.photobucket.com/albums/qq128/conanbear/SANY0071.jpg

http://i440.photobucket.com/albums/qq128/conanbear/SANY0072.jpg

http://i440.photobucket.com/albums/qq128/conanbear/SANY0073.jpg

http://i440.photobucket.com/albums/qq128/conanbear/SANY0074.jpg


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## butcher

Ahh weed burner, the reason I aske is I have been making my own propane burners, and was curious of the desighn, love yer furnace, thanks


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## Refiner232121

Hi scrapdealer 
I would like to build a furnace and I like your idea

If I bought one of these could I make a furnace like yours
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91899
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91894


Also in your first picture I see the burner attached to the furnace
How is that being held up there
Are you holding the burner with your hands or did you make something to have it stay like that
Maybe you can show a picture 


Also about picture 3 and 4 
Can you explain what that is
Thanks


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## dick b

Really nice job building the furnace. It looks very professional and should work very well for you. 
dickb


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## butcher

refiner those small propane burners from harbor frieight would work for small coffee can type furnaces, harbor freight sells weed burners similar to what scrap dealer is using, they may not get hot enough for gold, if you want to build a furnace or burner find backyard metal casting sites, and others, propane or other gas burners are easy to build, or can be scavanged from old appliances,
http://www.google.com/search?hl=en&q=backyard+metal+casting&aq=0&oq=backyard+met&aqi=g8g-m1

http://www.google.com/search?hl=en&source=hp&fkt=3031&fsdt=2562&q=reil+propane+burner&btnG=Google+Search&aq=f&oq=&aqi=


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## goldnugget77

When making a furnace like this
Can someone tell me what kind of material you place in the centre as a form before pouring the refratory.
Is cardboard a good idea.
Then you can just burn it
Thanks


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## Barren Realms 007

goldnugget77 said:


> When making a furnace like this
> Can someone tell me what kind of material you place in the centre as a form before pouring the refratory.
> Is cardboard a good idea.
> Then you can just burn it
> Thanks



Cardbaord like from a box is not rigid enough. You can use soni tube that piers are poured with or a piece of metal stove pipe.


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## goldsilverpro

The last place I worked used round cement forms made of very thick cardboard. They are about 1/2" thick and won't collapse. The ones I saw had a plastic coating on both sides so the water won't soak in and weaken it. Many companies make them. They are available at places like Home Depot and Ace Hardware. The price for a section 10" dia x 48" long seems to be about $8. Some of them are made to peel away in layers once the cement has set. Here's the sizes that one company makes.
http://www.sonotube.com/sonotube_round_size_chart.html

For big furnaces, a friend of mine used fiber drums for a mold, although you have to put wooden stretchers in them to prevent them from collapsing and it's a bear to remove that metal ring at the bottom (I am thinking that he burned out the fiber drum and left the ring in there). For very, very small furnaces, I have used large coffee cans as a mold. Stove pipe works and is easier to remove because it has a collapsible seam. A small coffee can, or other type can, depending on the size you want, works well for the hole in the lid.

In building a furnace, I always start with the dimensions of the maximum crucible size I want to use and go from there. I prefer the "bilge" shape with a spout. I also prefer silicon carbide although clay/graphite is good also, especially for certain things. This link gives the dimensions of the various sizes. Looking at their prices, though, their name, "Budget", doesn't seem to fit too well.
http://www.budgetcastingsupply.com/Crucibles.php 

According to the chart, a #10 crucible is about 6.5" wide at the bilge x 8" tall. For that size, I like about a 2" spacing between the crucible and the furnace walls, and 2.5" - 3" (I prefer 3") thick refractory for the floor, walls, and lid. The cardboard tube mold would, therefore, be about 10" diameter. Probably, those tubes are measured by the I.D. The metal shell would be about 15" - 16" dia. The height of the shell (not counting the lid) would be about 8" (crucible height) + about 1.5" (pedestal thickness) + 2.5" (floor refractory thickness) + 2" to 3" (space between top of crucible and top of furnace) = 14" - 15". With this size furnace, you could use a #10 crucible, or smaller. All these figures are ballpark. Measure everything before you build. If you go an inch or so bigger, it will be OK. You might be able to squeeze a #16 in there if you go about an inch taller and wider. For the dimensions I gave above, with 2.5" refractory and a 15" furnace diameter and height, it will take about 1.5 cubic feet of refractory, including the lid. For 3" thick refractory, it will take about 1.75 cu.ft. Use 3000F refractory. The cubic feet are marked on the bag. All manufacturer's bags are not the same. 

For just melting karat gold scrap, a #4 or #6 would probably be adequate. Just remember that you can use a small crucible in a big furnace, but not the other way around. I've even seen people fire 30 gram assay crucibles (when doing assay fusions) in a #20 furnace. When I was pouring 10 oz and 100 oz pure silver bars, in a graphite book mold, I used a #6 or a #8 crucible in a #20 furnace.

*NOTE: Do not accept my figures on anything, since I figured it hurriedly. Calculate everything yourself. I am just trying to give you some general design size ideas.*


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## Refiner232121

http://elliscustomknifeworks.hightemptools.com/images/12inchvertical1.jpg

I know that these burners can also be made but I am going to buy one of these


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## goldsilverpro

> I know that these burners can also be made but I am going to buy one of these


Their prices are reasonable but burners are very easy to make, especially those for natural gas. Ready made burners do give the builder a little peace of mind, though.


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## goldnugget77

Hi Chris & Barren
Thanks for those good ideas

How would I have this tube suspended in the right location while I am pouring the refractory.
I thought about placing wires underneath the sonotube
http://www.sonotube.com/sonotube_round_size_chart.html


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## goldsilverpro

> How would I have this tube suspended in the right location while I am pouring the refractory.
> I thought about placing wires underneath the sonotube


I have never personally used these tubes, but I have seen them used quite a few times. Unfortunately, I didn't pay as much attention as I should have. Here's what I remember. The tube is not suspended. You pour the floor first. When it is solid, but not fully cured (you want to get good bonding, I would assume), you just set the tube on the floor and center it. At first, add a little cement (maybe, a couple of inches deep) all around and tamp it so as to center the tube at the bottom. Add a little more, all around, and tamp a little. Soon, you have enough heavy cement all around to keep it from moving. At that point, you must make sure the top is centered. Repeat until it is full and smooth out the top.

Surely, someone else has actually used these tubes. Any comments or hints from them? Did you burn the tube out or, in some way, remove it. I seem to remember some guy on the internet cutting the tube all the way down the length first and then sealing the cut with duct tape (or, ?). Then, he added the cement. The seam made it easier to get out. Anyone tried this?


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## Barren Realms 007

GSP, 

That is correct on the sono tube. Cutting it length ways will be the best way. Make sure your seam is very secure when you start tamping the refactory or your pipe at the seam will start to move. A piece of 1" plank secured inside the sono tube so that seam can't move is recomended.


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## Palladium

I use to use them when i built the afterburner units for sweat furnaces. I would spray them with oil first and then just do what we call a burnout and just let them burnout. I've also used oil coated pvc pipe and pulled it back out.


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## Lou

I use sonotubes. You can put heavy axle grease on them and they slide out. You have to do the base first as Chris said, but as long as the refractory is still green and not fired, you won't have issues with it forming a monolith. 


Lou


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## goldsilverpro

> I use sonotubes. You can put heavy axle grease on them and they slide out.


Great idea, Lou. Grease mold release.That's definitely the way I'll do it the next time I build one, which will probably be soon.


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## golddie

I would like to buy a burner like this
http://elliscustomknifeworks.hightemptools.com/images/12inchvertical1.jpg


Also
Kast-O-lite 30 LI Insulating Castable Refractory:
for
55 pound bags - $65 per bag

The problem is that I wrote to them asked if they dilver to Canada and they did not reply
Does anyone know a company in Canada


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## golddie

Hi People I found a company that has a distributor in Canada
http://mtsavage.com/



> We have a distributor of our products in Quebec, Materiaux Refractaires Direct. The contact there is Daniel Labrie. His phone # is 1-866-526-9849.



-------------------------------------------
As for these people they dont even reply
They are stinkers
I am still looking for a burner like the one in this picture if anyone can help that would be nice
http://elliscustomknifeworks.hightemptools.com/images/12inchvertical1.jpg


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## Barren Realms 007

golddie said:


> I am still looking for a burner like the one in this picture if anyone can help that would be nice
> http://elliscustomknifeworks.hightemptools.com/images/12inchvertical1.jpg



That burner is one that was made by an individual it is not something that is available in this style to the public.


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## golddie

the guy is selling this on his web site 
If you click on burners and burner kits
its there



> http://www.elliscustomknifeworks.com/
> 
> 
> 
> 
> Forced-Air Burner:
> $105.00
Click to expand...


Maybe I should make it myself


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## golddie

Hi Folks 
I am going to try to make a burner like this
with plumbing pipes and valves from my local hardware

http://img693.imageshack.us/img693/2030/12inchvertical1.jpg
http://img5.imageshack.us/img5/2614/forcedairburner.jpg

Everything seems very straight forward
Where I have written No 1 
That is for the blower 
and I am guessing that the valve needs to be adjusted
according to the amount of gas that is needed for the fire.

This is the part I need help with because I am not sure as to the
way it work

http://img5.imageshack.us/img5/2614/forcedairburner.jpg
No 2 and 3
This must be for the connection for the propane gas.
I would assume that one valve would be enough to make 
the adjustments for the gas pressure.

Here is my important question
What are those levers I have marked 2 and 3
If it is for adjustment then why have 2 levers or whatever they are.

That part where it is written 2 and 3 
Can I buy a part that is similar to this but with only 1 valve
Thanks


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## golddie

Hi People
There must be someone out there that will make a blower for my furnace and ship it to Canada
I dont want this free.
I am not crazy about the idea of making one
Thanks


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## Barren Realms 007

Hi Golddie, 

This is a a very simple setup they have there. Guess I should have known someone had one for sale.  

The #3 is a ball valve quick open and close. The #2 is just a diffrent kind of valve that will allow you to fine tune the volume of gas delivered to the burner. 

Heck take the picture you have to your local hardware store and they can help you pick the items out. 

If you were close I would build it for you I probably have everything in my shope jusy laying around to to this. But the shipping would probably cost more than the parts. 

Where are you located at?


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## golddie

Hi Barren Realms 007
Thanks for your help
I am in Montreal Canada

How much would that cost me without the shipping.
Well add the shippping on top of this
Thanks


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## Barren Realms 007

To be honest more than what he is charging for that set up.


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## golddie

Hi Barren
Thanks for your help 
I can understand that because its always cost more to do something on special order
He probably mass produced them
I will check my hardware store tommorow or the next day and see what happens 
If I cant manage I can always depend on my buddy Barren Realms 007 
Thanks and Take care


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## Barren Realms 007

No problem. If your hardware store dosen't have them you can find them from a commercial piping supplier. Plumbing, gas piping. Don't get hung up on the details and you might be suprised what you can build.


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## golddie

Hi Bareen
Thanks for your help
If I was in your area I would drop by for a coffe.
You seem like a real nice person.

I just got an e-mail from 
http://www.elliscustomknifeworks.com/
She said that they will deliver and i spoke too quickly and called them stinkers and I was wrong and I appologize.

I am not sure what I am going to do but I wil make up my mind soon
Thanks


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## golddie

http://mtsavage.com/
I called the local distrubutor here and talked to him 
I will order a refractory that is the equivalent of
Kast-O-lite 26 LI Insulating Castable Refractory:

I wanted to have the 
Kast-O-lite 30 LI Insulating Castable Refractory:
but they dont have.

Anyway my question is this 
How much material do I need 
This is a 20 pund tank.
I will buy some extra but still I need to know how many cubic inches this tank has ,so when I mix the refractory I wnt mix too much
Thanks


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## Barren Realms 007

See if this helps you.

http://www.onlineconversion.com/volume.htm


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## golddie

Hi Barren 
Thanks for that great web site.

This is what I did
I converted 20 Lbs to ounces
20Lbs=320 Ounces

320 ounce [US, liquid] = 577.500 000 01 cubic inch

Does this mean 
577 cubic inch 
---------------------------
I wanted to get the 
3000 degree F 
refractory material
I don't think this guy has that
I am thinking that if I want to melt platinum I wont be able to
What do you folks think


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## Barren Realms 007

If you put the info in there correctly it should be the right answer.

If you are wanting to melt platinum you will not be able to do it in a setup like this. You will only be able to melt in a few grams per melt. Recomendation is to press the sponge into a puck and melt it in a small crucible.


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## goldnugget77

Is it necessary to to fire the furnace before using it
I saw a fellow put charcoal and burn a fire 

If you do this,for how long must you burn the charcoal


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## Barren Realms 007

If it is a new furnace yes it should be done. Put you about 10 charcoal bricquetes in the furnace for about 3-4 hrs to dry it out and then slowly crank up the temp to finish cureing the furnace to operating temp. You will want to do this slowly so you don't crack the lineing.


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## goldnugget77

Hi Barren
Thanks for that reply
http://elliscustomknifeworks.hightemptools.com/images/12inchvertical1.jpg
$ 105 
-------------------------------
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=91033
$24.99
Heats up to over 3000º F 
-------------------------------
3/4" Venturi Burners:
$80.00

The torch that is $24.99 from harborfreigh seems like a good deal.
However the one sold by elliscustomknifeworks look more professional and better
Actually I am thinking about buying all 3 of these.
I would be nice to have your opinions
Thanks


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## Barren Realms 007

Each one are good setups for diffrent uses. I have seen all 3 of them in action and they will work. It will just take your experinceand work to decide which one you will like using the best. Always remember your operating cost.


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## PreciousMexpert

I decided to have

1) 
http://elliscustomknifeworks.hightemptools.com/images/12inchvertical1.jpg
-------------------------------
2)
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=91033
-------------------------------
3)
3/4" Venturi Burners:
-------------------------------
4)
Also another small torch

That makes 4 torch places in all
http://shorinternational.com/TorchAcesory.htm
Here I am at I shor 
and I dont see any connector for such a thing
What is the proper terminilogy for such a multi propane connectors
and where can I buy one
Thanks


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## Barren Realms 007

Contact a welding supply house for that type of stuff.

Can I makea suggestion get a MAPP gas hand tourch and practice with that till you know what you are doing and have a better idea of what you will need. It is a great handy device and you can accomplish a lot with it. If you need me too I will post a picture of one. You have way too much over kill in what you are looking at using.


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## PreciousMexpert

Hi Barren
Thanks for your help
I have done plenty of soldering in jewelery with a torch.
You are right about in saying that I have too many torches

Maybe you can give me advice
I already have a torch that used by jewelers and I would like to attach that to the propane tank
Also I would like to have a torch for a furnace with a blower.

So I am saying 2 will be enough 
But lets say I want to use a venturi burner
It will be a hassle to change it and also can damage the equipment
Thanks


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## Barren Realms 007

Ok now that bit of info helps a lot it shows that you know how to use a tourch. I have to get to work but I will be back this afternoon and see if I can make some short videos of the tourches I am talking about.

That big unit what are you planing on doing with it? The pot furnace I will call it with the red piping for the burner.


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## PreciousMexpert

Hi Barren
Thanks for your help
The burner that is painted red will be new to me I have never had a furnce with a blower.
I plan on melting bars in a crucible and making cornflakes and refining


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## Barren Realms 007

I assume you mean you are going to inquirt gold in this? One of the other more knowlegable people here will have to say if that is fesable in this unit I think it will be say with a #10 crucible? Or what size are you planing on using that will make a big diffrence in what you build.


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## goldsilverpro

A #10 crucible is pretty big. For inquartation of karat gold, I would imagine a #4 or #6 would be fine. Just remember that you can always put a small crucible in a big furnace, but not visa versa. As long as you're putting the effort into building a furnace, I would build one bigger than what you think you need. The added time and cost of building a little bigger furnace is not that great. You never know what the future will bring. The last furnace I built was a #20. I poured many 100s of 10 and 100 oz silver bars in graphite book molds using a #6 or #8 crucible in this furnace. For general melting and pouring silver cell bars, I usually used a #16 or #20 crucible.

The number size of the crucible is equal to the weight of aluminum that it will hold, in pounds. I think this is brim full but, of course, you'll never completely fill the crucible. I would figure a max of, say, 1/4 to 1/3 full, for gold or silver. The S.G. of aluminum is about 2.7 and the S.G. of a 25% Au/75% Ag-Cu alloy is 11 something. Therefore, you can get about 4 times more inquarted gold in the crucible than you can aluminum. A #4 crucible, 1/4 full, would therefore hold about 4 pounds of inquarted gold, if my math is right. That's a lot - a pound of actual gold content.


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## Barren Realms 007

GSP could you possibly explain what you run into in trying to keep heated a large qty of gold like this to pour. I feel you can get the point across better than I can. I don't think people understand the problems of trying to heat up quantities like this.


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## dick b

Barren Realms 007:
Have you looked at this furnace?
http://www.backyardmetalcasting.com/bucketfurnace2.html
http://www.backyardmetalcasting.com/oliverburner1.html
dickb


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## goldsilverpro

> GSP could you possibly explain what you run into in trying to keep heated a large qty of gold like this to pour. I feel you can get the point across better than I can. I don't think people understand the problems of trying to heat up quantities like this.



That's hard for me to answer because I never thought much about it. Of the many 100s of melts I've made, I only remember a few times that the melt froze before I poured it. Usually, that was because of something dumb I did. For example, I pulled the crucible out, only to realize that I hadn't prepared the mold yet or, maybe, I hadn't yet dumped the metal out of the mold from the previous pour. When this happens, I just put the crucible back in the furnace and re-melted the metal. You soon learn how hot the melt should be in order to not have any problems. Generally, you can do this by looking at the colors. When the material isn't well melted, it will be darker than the color of the inside of the furnace. Depending on what you are melting, the right color is often yellow or light yellow. When it's ready to pour, the furnace, crucible, and melt will all be very close to the same color.

You have to look into the furnace often and you can't do that without the right equipment - it's too hot. An old method is to make a square ping-pong like paddle about 12" x 12" square, or so, with a handle, out of about 3/8" plywood. In the center, cut a slot about 1/8" wide x 4" long, vertically. The kerf should be about the right width with a circular saw. To look in the furnace, you just hold the paddle to your face and look through the slot with one eye. I usually don't remove the lid to look at the melt. I look through the exhaust hole in the lid, which is usually about 4" wide on a #20 furnace.

If you have problems getting enough heat to get a good melt, it is usually because the furnace isn't adjusted properly or the gas pipe wasn't large enough to start with. 

Here's how I used the natural gas furnace: 
(1) I put a piece of burning paper in the furnace chamber and partially turned on the gas only - no air. Leave the lid off. Adjust the gas till it swirls to about the top of the chamber.
(2) With the lid off, let it heat the furnace for 5-10 minutes. 
(3) Then I closed the lid and let it heat the lid for a few minutes. Adjust the gas so the flame is coming out of the exhaust hole in the lid about 6" - 8". *Warning*. If you close the lid too early, before the chamber is heated up properly, the flame can go out. If this happens, shut the gas off and turn on the air to exhaust the fumes from the chamber. Turn the air off and start over
(4) Turn on the air slightly. The flame (the tail) coming out of the hole will be shorter. Adjust the tail until it is about 3" long. At this point, the roar of the furnace should be about maximum.
(5) Let the furnace heat until it's about yellow inside - maybe 45 minutes. You may have to adjust the tail every so often. Just remember - more gas, longer tail - more air, shorter tail.
(6) For certain things, you need the furnace to be hotter or cooler. To raise the temp., first increase the gas (the tail will get longer) and then adjust the tail down to about 3" with the air. To lower the temp., first decrease the air (the tail will get longer) and then decrease the gas to about a 3" tail. *Warning.* The order of making adjustments is extremely important. If you do it in reverse, you will have not tail and you can blow the flame out. For safety sake, you should always have a tail.


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## Barren Realms 007

goldsilverpro said:


> You have to look into the furnace often and you can't do that without the right equipment - it's too hot. An old method is to make a square ping-pong like paddle about 12" x 12" square, or so, with a handle, out of about 3/8" plywood. In the center, cut a slot about 1/8" wide x 4" long, vertically. The kerf should be about the right width with a circular saw. To look in the furnace, you just hold the paddle to your face and look through the slot with one eye. I usually don't remove the lid to look at the melt. I look through the exhaust hole in the lid, which is usually about 4" wide on a #20 furnace.



Excellent explination GSP. Thank You.

Might I suggest a set of cutting goggles to look thru or a welders helmet.


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## PreciousMexpert

Hi Barren
I was wondering about the videos you said you would make
That would be intresting to watch


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## Barren Realms 007

dick b said:


> Barren Realms 007:
> Have you looked at this furnace?
> http://www.backyardmetalcasting.com/bucketfurnace2.html
> dickb



I missed this post earlier.

I'm glad you posted that, I have been thinking about that burner for the last couple of days. There is a break down of that burner some where on the web site would you mind finding it and posting a link to it.

I'm going to see if I can get one of these short videos made.


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## Barren Realms 007

Ok I hope this is informative and helps on some questions on tourches. 

Here are a couple of videos and some pictures comparing a MAPP gas tourch like Lasersteve uses and what in the plumbing trade is called a B-Tank(Acetelyne) in our area with a turbo tourch setup with quick connecting tips that range from pencil size to about 3/4" in diamater. 

I have used these tourches on copper piping up to 4". Using lead solder just before the new 95/5 solder was required for use in potable water systems. A single tourch for 1 pipe connection with the largest tip.

I have silver soldered 4" copper in 35 deg temp with heavy wind blowing, it took 2 tourches working on the same joint to complete the job.

This set of pictures shows the MAPP gas tourch. I think the last one I purchased was around $95.00.










The following pictures are of the B-Tank. The tank cost about $85.00 last one I purchased. The regulator and handle with quick connect probably $85.00-175.00. The tips run from $65.00-300.00 or more for the larger ones. These tips you treat like fine china, you don't just beat on things with them while in use it ruins the internals and they will not work afterwards.


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## Barren Realms 007

Continued.


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## Barren Realms 007

Here are some videos for your enjoyment.

http://www.youtube.com/watch?v=cDI3pP1suLA

http://www.youtube.com/watch?v=tWkxtwIebLw

http://www.youtube.com/watch?v=MpMwLMEOGKw

The melting point of copper: 1983 F
The melting point of gold: 1945 F


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## Barren Realms 007

Here is a kit that some might be able to use. Pay atention to the burner desighn.

http://www.backyardmetalcasting.com/hmkit.html


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## dick b

Barren Realms 007:

I edited my earlier post and added the link for the burner. Here it is again
http://www.backyardmetalcasting.com/oliverburner1.html
I have made a couple of these in different sizes and they work real well.

Dickb


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## PreciousMexpert

Hi Dick b
Thanks for the link

Hi Barren 
Thanks for those pictures and the videos , they were very helpful.
For starters I am going to buy this torch
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=91033

I see that it does not need an oxygen tank its like a mapp gas torch.
I can even melt platinum with that


I dont know about the kind of regulator I will nedd
http://search.harborfreight.com/cpisearch/web/search.do?keyword=regulator&Submit=Go


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## Barren Realms 007

PreciousMexpert said:


> Hi Dick b
> Thanks for the link
> 
> Hi Barren
> Thanks for those pictures and the videos , they were very helpful.
> For starters I am going to buy this torch
> http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=91033
> 
> I see that it does not need an oxygen tank its like a mapp gas torch.
> I can even melt platinum with that
> 
> 
> I dont know about the kind of regulator I will nedd
> http://search.harborfreight.com/cpisearch/web/search.do?keyword=regulator&Submit=Go




You will not be able to do platinum with that tourch.

The regulators in that link are pressure reducing regulators for compressed ait like from an air compressor. Not to be used with oxy/acet/propane and similar components.


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## PreciousMexpert

Hi Barren
Will I be able to melt gold with that 
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=91033


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## Barren Realms 007

It is fesable in that pot furnace to melt gold with it. This tourch is used for heating large areas. You want to be looking at a tourch that concentrates the flame to a smaller point. Look at the videos again and you will see where I have my flames at. At the edge of the blue flame that is your hottest area and you want this concentrated to apply the heat correctly.


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## PreciousMexpert

Hi Barren
Can I melt gold and platinum with this



> 3/4" Venturi Burners:
> 
> Completely assembled and ready to install in your forge.
> 
> These Venturi burners will heat a typical well insulated forge volume of approximately 350 cubic inches up to forge welding temperature!
> 
> 
> - Requires propane hose, regulator (0-30 psi), and POL fitting (see below!).
> 
> - May require some tuning for your particular forge, but it's easy to do!
> 
> $80.00
> 
> 
> The Video below shows one of our Venturi Burners operating over the pressure range of 1 - 30 psi. Click the "play" button to view



http://www.elliscustomknifeworks.com/


----------



## Barren Realms 007

PreciousMexpert said:


> Hi Barren
> Can I melt gold and platinum with this
> 
> 
> 
> 
> 3/4" Venturi Burners:
> 
> Completely assembled and ready to install in your forge.
> 
> These Venturi burners will heat a typical well insulated forge volume of approximately 350 cubic inches up to forge welding temperature!
> 
> 
> - Requires propane hose, regulator (0-30 psi), and POL fitting (see below!).
> 
> - May require some tuning for your particular forge, but it's easy to do!
> 
> $80.00
> 
> 
> The Video below shows one of our Venturi Burners operating over the pressure range of 1 - 30 psi. Click the "play" button to view
> 
> 
> 
> 
> http://www.elliscustomknifeworks.com/
Click to expand...


With the venturi burner yes you can melt gold with a burner of this type. The burner and burning chamber will need to be matched so you can keep your temperature up. You don't want to put an 1/8" supply line on a 30 gal pot(not enough BTU input) and you don't want to put a 1" burner on a 3 gal pot(too much BTU input. Always try to keep an eye on your BTU output rating as this is the amount of heat you are developing.

For platinum you will need a set up like an oxy/acet set up but you can not use acet because it can contaminate the metal with carbon when melting. In place of acet it is recomended to use propane.

The refractory needs to be rated for 3,000 deg. The bag's you order should be date tagged because the refractory has a shelf life if not used.


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## PreciousMexpert

Hi Barren 
Thanks very much for helping me out.


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## goldsilverpro

You're not going to have any luck melting platinum in a typical gas crucible furnace. The melting point of Pt is 3215 F. With a natural gas furnace, for practical reasons, the upper limit is about 2300 - 2400 F, and that's difficult to obtain. Unless you spend a lot of money, the highest temperature rating of common refractory is about 3000 F. I know from experience that SiC crucibles can soften at white heat.

There are basically 3 ways to melt platinum: resistance melting, induction melting, and torch melting. As I recall, Ms. Hoke's daddy developed the first practical torch to melt platinum. It was called the Hoke torch and it is still sold. I think it originally used H2/O2 and some sort of lime melting dish for platinum.

Here's a chart of temperature colors that I posted earlier. I took it from a fire assay book. Note that white is about 2200 F and above. When the furnace and what's in it turns white, you can barely see the crucible. It's very hot to work around white heat and, with even a medium sized furnace, protective aluminized clothing is needed.

APPROXIMATE FURNACE TEMPERATURE COLORS

Lowest red visible in the dark.......... 470 C ..... 878 F
Dark red, blood-red....................... 550 C ..... 1022 F
Dark cherry.................................. 625 C ..... 1127 F
Cherry-red, full cherry................... 700 C ..... 1292 F
Light red....................................... 850 C ..... 1530 F
Orange......................................... 900 C ..... 1652 F
Light orange.................................. 950 C ..... 1742 F
Yellow........................................... 1000 C ... 1832 F
Light yellow................................... 1050 C ... 1922 F
White.................................... 1150-1200 C ... 2102-2192 F


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## goldsilverpro

> Might I suggest a set of cutting goggles to look thru or a welders helmet.



I like to see the colors. Actually, with a small furnace, low to the ground, you can take quick looks with just a clear face shield.


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## Barren Realms 007

goldsilverpro said:


> Might I suggest a set of cutting goggles to look thru or a welders helmet.
> 
> 
> 
> 
> I like to see the colors. Actually, with a small furnace, low to the ground, you can take quick looks with just a clear face shield.
Click to expand...


Me and you know this along with other experienced people here. But new people don't realize the danger in looking at heated items like this and don't realize it takes but a few seconds of aw amazing color and bam your eye's are possibly damaged. That was the reason for my recomendation. Your idea was excellent as well and has been used for many decades.


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## dick b

"You will not be able to do platinum with that tourch." Quote

I agree. Iron is about the max you can melt using air aspiration and propane.
Remember the blacksmith used air and coke to hammer weld iron.

dickb


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## Oz

dick b said:


> Remember the blacksmith used air and coke to hammer weld iron.



Platinum melting,no. But I have forge welded up to 3/4" using a propane forge.


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## PreciousMexpert

Hi Oz


> forge welded up to 3/4" using a propane forge


This is intresting can you tell us more about this 
Thanks


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## Barren Realms 007

PreciousMexpert said:


> Hi Oz
> 
> 
> 
> forge welded up to 3/4" using a propane forge
> 
> 
> 
> This is intresting can you tell us more about this
> Thanks
Click to expand...


It is taking 2 pieces of Iron and heating them in a forge with added air flow to increase the heat till they are glowing close to melting temp. They are then placed on an anvil and beat till they are fused together.

This is not to be confused with layering metal the way that true oriental swords are made.


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## goldnugget77

Hi Barren
That is intresting
Can you join metals in this way withoult solder or welding sticks


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## Barren Realms 007

goldnugget77 said:


> Hi Barren
> That is intresting
> Can you join metals in this way withoult solder or welding sticks



It is a crude and backwards way of joining metals together. But yes as far as know I virtualy all metals can be done this way if you can get them hot enough. This will not give you the same hamoginous mix as if the metals were melted together because this is being done with force.

There is a company that does work for the US Armed forces that will take 2 diffrent kinds of metal and place them on top of each other. They put an even coat of explosives on top of the metal as a powder. When the explosive is detonated it fuses the 2 metals together. I think they are using it in armor plating, been a while since I have seen the report.


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## goldsilverpro

> There is a company that does work for the US Armed forces that will take 2 diffrent kinds of metal and place them on top of each other. They put an even coat of explosives on top of the metal as a powder. When the explosive is detonated it fuses the 2 metals together. I think they are using it in armor plating, been a while since I have seen the report.



Sounds like thermite welding. I think they used to use that for railroad rails.


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## Barren Realms 007

goldsilverpro said:


> There is a company that does work for the US Armed forces that will take 2 diffrent kinds of metal and place them on top of each other. They put an even coat of explosives on top of the metal as a powder. When the explosive is detonated it fuses the 2 metals together. I think they are using it in armor plating, been a while since I have seen the report.
> 
> 
> 
> 
> Sounds like thermite welding. I think they used to use that for railroad rails.
Click to expand...


Nope that is a completely different process. That is a melting process. This is a force fusion process. No extra heat is involved just the impact of the explosion. It does not mix the metals, they still stay in ther original form but where they meet together they are fused together.


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## Oz

I have always done my forge work with bituminous coal forges. But I have had 2 occasions were I was provided the opportunity of forge welding out of a propane forge. Both forges were naturally aspirated propane forges that did a good job of reaching a welding heat. 

There is far greater detail than I will go into here as to the manufacture of the oriental swords of old but they were forge welded. Before the invention of Henry Cort's puddling furnace to produce wrought iron in decent quantities and the advent of small rolling mills, iron was produced in small batches in a bloomery furnace. Now a bloomery furnace is much smaller than one would imagine being about the same size as a typical forge of the time. The metal produced was very inconsistent as to quality and carbon content. One bloom may be nearly free of carbon and another be steel, the solution to this (other than setting aside some steel blooms for cutting edges like the bit in an ax) was to take 2 or more blooms and forge welding them together. It was then repeatedly drawn out and folded over on itself as a forge weld, in this way giving a more homogeneous mass. If executed properly this process also removed excess carbon that made the iron too hard and brittle for most applications.

Later they found they could take these blooms to a welding heat and run them through rollers and they would weld, saving much labor. If you look at old wrought iron that has corroded or you can grind and etch yourself you can see the different layers like a wood grain (this is the grain you see etched in old swords, but finer in the blade by far). Then came Henry Cort's puddling furnace that revolutionized iron manufacture giving good consistent low carbon wrought iron. It was still run through rolls and welded upon itself as this removed dross (molten silica) from the iron and improved the quality in general. They actually sold this in different grades dependent on how many times it had been through the rolls.

On a last note the making of wrought iron is actually a high temperature chemical reaction using carbon monoxide to reduce the iron ore not a simple melting process.

Harold may wish to elaborate further.


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## Barren Realms 007

Oz,

Very good post. 

The only reason I mentioned the oriental swords is because it is my understanding that they are folded in layers. If I remember right I think there is something added between layers. This give the metal more flexability and a better edge can be put on the sword.


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## Oz

I am purposely staying away from the term Damascus steel as there are more than one type and it would get confusing and serve no point here. For the purpose of this conversation I will define what I am talking about as folded and welded sword and knife blades.

Fine swords were folded and forge welded. As an example you would take 5 slabs of iron and forge weld them together then draw them out to double their original length and cut it in half, these 2 halves were then forge welded together giving you 10 layers. 

The value in this is not to gain homogeneity of the iron but to layer 2 different irons with differing characteristics . Your original 5 layers would alternate between very high carbon and low carbon iron. As this process was repeated the layer count increases and the layers become thinner. When the finished product was tempered you would have thin layers of very hard high carbon steel that would shatter like glass if the blade was struck against an object. However having alternating layers of low carbon steel that will not harden bonded between hardened layers gives a cushion or support to them. It is the best of both worlds as you can have a far harder tool steel edge that will perform better than a low carbon soft iron edge with a greatly reduced risk of damage in use. 

A crude example is the hand forged ax. If the whole head where made of highly hardened tool steel it would shatter even chopping wood. However if you have but a thin leaf forge welded in the center of an ax head (the bit of the ax) and the remainder low carbon iron you can give the piece a relatively hard temper (a dark straw to light blue) and it is only the bit that will be hardened due to the different carbon contents. Your leading edge will always be high carbon but will be cushioned by the low carbon giving far less risk of damage for the same level of hardness of your “working” edge. 

This is a simple explanation of a very complex subject of course. I would enjoy hearing Harold's input and commentary given his machinist background.


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## goldnugget77

BURNER
http://elliscustomknifeworks.hightemptools.com/images/venturi.jpg
$45.00
-----------------------------
http://www.zoellerforge.com/zburner.html
Z Burner™
$60.00 
-----------------------
http://www.zoellerforge.com/flare.html
Side Arm Burner kits
$45.00
________________________________________________
PRPOANE REGULATOR
Single Burner Connection kit.
http://www.zoellerforge.com/flare.html
$75.00
--------------------------
0 - 17 PSI Propane Regulator/Assembly Kit:
http://elliscustomknifeworks.hightemptools.com/propaneregulators.html
- Assembly kit with 10 foot propane hose & pressure gauge - $56.95


********************************************************
SUMMARY
1) The total is about 120 dollare if I buy from ellis
2) The total is about 120 dollare if I buy from zoeller( Side Arm Burner kits)
3) The total is about 135 dollare if I buy from zoeller( Z Burner™)
The dollare differnece is nothing here its only by a few bucks
My problem is that I cant decide on which model to choose.
I have numbered the combination 1,2,3
If you can give me your opinion on which number that would help
Just tell me 1or 2 or 3
Thanks


----------



## Barren Realms 007

They are all about the same toss a coin and make your decision.


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## goldnugget77

Thanks fo that info Buddy.


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## golddie

http://img838.imageshack.us/i/dscf0044u.jpg/
http://img718.imageshack.us/i/dscf0043q.jpg/
http://img836.imageshack.us/i/dscf0045q.jpg/
http://img80.imageshack.us/i/dscf0046e.jpg/

Question about the black pipe
the fact that its not welded will this be a problem
the other parts are all welded
should i use the furnace without that pipe



Question about the broken handle on the burner
everything on the handle is fine will that broken handle be a problem

Question about the refractory
I didnt order enough material so as you can see the can was not completely filled
and i wasnt able to make a cover so I have to do something about that and also

Question about pipe in refractory
that pipe is not supposed to be there and I cant remove it
someone said use axle grease and i did that but it is stuck there
maybe i didnt use enough grease
what should i do about that
I am thinking of leaving it there but i said maybe it will dislodge during when I am using the furnace 
and maybe it could be a problem

Thanks


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## golddie

Hi Barren
Thanks for your help
Someone told me that if I use the furnace without removing that pipe in the refractory than I might get a bid crack in it so i will try your idea.

about that part where I didn't have enough refractory material I am going to cut it off and it will be a furnace shorter than I anticipated


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## golddie

http://img838.imageshack.us/i/dscf0044u.jpg/
I tried what you said Barren and it didnt work and I got to find a way to remove that thing


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## golddie

http://img838.imageshack.us/i/dscf0044u.jpg/
I am able to hammer this pipe inward but it wont come out of there.
I tried to turn it and make it loose and that wont work.


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## Barren Realms 007

golddie said:


> http://img838.imageshack.us/i/dscf0044u.jpg/
> I am able to hammer this pipe inward but it wont come out of there.
> I tried to turn it and make it loose and that wont work.



Have you tried to use a pipe wrench with a cheater bar on it?


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## golddie

Hi Barren
I dont have a pipe wrench so what I did was I took my table wrench which is very sturdy maybe sturdier than a pipe wrench
The reason it goes inwards is because I am able to hammer it very hard but when it come to hammer it the other ways I cant because of the positioning .


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## oldgeek

I have a way...But it will not be fun.

Cut pipe off 1 inch from outside furnace wall. Use a metal blade on a sawzall to notch the pipe lengthwise from the inside. 1 cut should give you enough room to squeeze the pipe together and slide it out. If you do not have a sawzall, you could use a hacksaw blade, wrapped with tape. (use it so when you pull on the blade, it cuts) I have used this method on PVC pipe a few times to save a "T" or something else i did not want to have to replace.

Good Luck!


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## lazersteve

Place a cap on the pipes external threaded end and then slip a large crescent wrench over the pipe. The crescent should be opened just large enough to slip over the pipe and no bigger. Snug the crescent up tight against lip of the cap on the furnace side. Now take a large sledge and gently tap the crescent wrench away from the furnace body. The cap should give you a edge to push against with the crescent as act as a lever that will force the threads of the pipe out of the refractory.

Steve


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## golddie

Hi Steve
This thing is so tightly in there that We have used a sledge hammer and banged it with 2 hands and now we don't have threads anymore.
The reason it goes inwards is because we can smash the pipe so hard that it was able to go in but we are not able to bang it with the same force in reverse
The thing I will probably try is what oldgeek suggested.
Thanks


----------



## Barren Realms 007

If you can't get either one to work. Cut the pipe off close inside and close outside and then get a long blade and cut the pipe in 2 places long the center so it splits and you cn get it out.


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## Oz

For whatever reason I cannot see the pics. If I am not mistaken though this is just an iron pipe stuck in refractory. Find someone with an oxy/acetylene torch with a bit of knowledge and just cut it out. I have burned stripped bolts out of an engine block without damaging the threads in the block. That was the last option in that case because both were iron, but in your case it should prove much easier with a thermally resistant wall the pipe is in.


----------



## Harold_V

Oz said:


> Find someone with an oxy/acetylene torch with a bit of knowledge and just cut it out.


A reasonable solution, although I'd recommend heating the refractory well before doing so. A considerable amount of moisture will be liberated. Too much too fast in an isolated area can result in a steam explosion, damaging the furnace and offering the risk of injury to the operator. 

Harold


----------



## golddie

The metal pipe is out of there and I am surprised that after all that banging with the sledge hammer the refractory didn't break.
I did have to cut the pipe from the inside and it was not fun 
so dont do this again just use a pvc pipe
I havent used it to melt anything yet I will let you all know the result


----------



## golddie

http://img718.imageshack.us/i/dscf0043q.jpg/
http://img838.imageshack.us/i/dscf0044u.jpg/
Now that I have removed the pipe and rimmed the top I need to make a cover for this furnace


http://goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=8487
This is a good idea but not practical in my case.


----------



## goldnugget77

http://img718.imageshack.us/i/dscf0043q.jpg/

The refractory was poured about 6 months ago 
Can someone tell me how the prepare something like this before actually using it to melt metal
Since it was poured 6 months ago do you think it might not be necessary to do anything like that
If yes do I burn charcoal or what 
Thanks


----------



## Barren Realms 007

goldnugget77 said:


> http://img718.imageshack.us/i/dscf0043q.jpg/
> 
> The refractory was poured about 6 months ago
> Can someone tell me how the prepare something like this before actually using it to melt metal
> Since it was poured 6 months ago do you think it might not be necessary to do anything like that
> If yes do I burn charcoal or what
> Thanks



Use you about 3-4 charcoal briquetts and let them burn to heat up and season the refractory after that batch double the amount of briquettes and repeat let this run and double again repeat this till you can fill your furnace up 50% with the briquetts and then run a blower into it and this should season your furnace and not have many problems.


----------



## Harold_V

Yep--I'd do something similar to what Barren suggested. Regardless of how long it's been allowed to sit, it will contain some free water. If it's converted to steam too quickly, you risk a steam explosion. I'd suggest you start by placing a 100 watt light bulb in the furnace for a day or so, allowing it to evaporate as much of the free water as it will. You should notice a difference in the surface, even with such simple heating. 

Harold


----------

