I agree guys, the opening can stand to be a lot smaller. The skillet I poured into is one of those ash tray cast iron skillets. I had used it to partially cover the opening and the change was drastic. The color inside went from a orange-red to a yellow-white color very quick. I need to get better set up to control the air flow, and I think a high pressure regulator for the gas would make the move to a fully working furnace. (although quite small) I have been using a regulator from a gas grill, and powering the air from dual nebulizers. I do have an adjustable gas valve but it doesn't seem to give quite the control it needs.
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Barren Realms 007
In Remembrance
Are you using propane or natural gas for your furnace? I will get you a picture of my furnace posted when I get a chance. It is a similar design to the furnace you have except for the burner assembly and it will eliminate the need for the nebulizer you are using.
I am using propane. I have changed the burner out to one of the Reil(?) type burners, but it still needs air assist to get hot enough. This is the current burner assembly I am using, it seems to work the best of the three. I scaled everything but the orifice size down by 1/2" to fit the small size of the furnace. My original worked great up to aluminum but that is about as far as I could seem to push it.
Notice the paper still on the burner pipe. That paper stayed there after a continuous 4 hour burn and I could still hold my hand within 4 inch's of the furnace with out being uncomfortable.
Notice the paper still on the burner pipe. That paper stayed there after a continuous 4 hour burn and I could still hold my hand within 4 inch's of the furnace with out being uncomfortable.
You might want to try a larger reducer. I can't tell if that's a 3/4" to 1/2" or a 1" to 1/2", but I'd suggest a 1-1/4" or 1-1/2" to 1/2". As close as the gas inlet pipe is to the 1/2" pipe, it may be restricting the air that is able to pass around the gas pipe.
Dave
Dave
Locally the largest single reducer I can find is 3/4 to 1/2. I had thought about using two to achieve a bigger opening but wasn't sure that would help. I just changed the regulator to a high pressure type and heating it up with no added air. I should know pretty soon what the effects that has on it pretty soon.
Edit: fix miss spell check,
Edit: fix miss spell check,
upcyclist
Well-known member
I made a Gingery Furnace once upon a time that did aluminum really well, and that was with charcoal and a blowdryerShark said:
That sounds like good insulation and nice tight tolerances--good job!Shark said:
Barren Realms 007
In Remembrance
Here are some pictures of the furnace I use. It is about the same size and setup as yours. It is capable of holding a #6 crucible but I use a #4 in it.
In the first photo you will see that the exhaust opening is a lot smaller than in your furnace. The opening is 2" across and the two side slot are 2" long as well. Most of the time when I am running the furnace I will put a brick over the side slots just to retain heat and not use as much fuel. It doesn't really make much of a difference when I close the side slots off on how the furnace operates.
In this second photo you will see that my burner pipe is a 3/4" pipe with a 3/4" x 1-1/2" bell reducer on the end of it for the inflow of air for the fuel mixture. I have seen these furnaces also setup with an added air supply from a compressor or other source to generate higher heat temperatures. But I don't feel that is necessary for this furnace at this point with everything I have used it for
In the third photo you will see that the burner inlet is a little bit more to the side of the furnace than your is but I don't think that will have much of a difference on your furnace. The reason for the side inlet where it is is so that it will create a vortex motion of the flame in the furnace. I think yours is fine where it is.
In this fourth picture you can see a #4 graphite crucible next to a 300ml beaker for size comparison. This furnace will reach an operating temperature hot enough to melt this crucible full of copper powder in roughly 30-45 minutes from a cold start. Once it reaches its melting temperature the copper can be poured and another load added to the crucible and melt the charge in about 10-15 minutes. The furnace does not have to be run at maximum out put to accomplish this. When my furnace is operating you can not touch the sides because of the heat generated, you have to use gloves even when using the handles to remove the top.
Another tip on the crucible is to not use a cheap clay one when running this furnace, if you look at the picture looking down into the furnace you can see that I used a couple of cheap crucible and they failed during the melt. Go ahead and spend the money to get a graphite crucible. The one in the picture is a salamander crucible I purchased on ebay for about $20.00 if I remember correctly.
1. I think you need to upsize your burner pipe to a 3/4" with a bigger bell reducer on the end for incoming air flow.
2. You need to reduce your exhaust opening.
3. I'm also not so sure that your gas pressure might need to be increased at your burner pipe. I am guessing that the propane is being supplied by the tank that you use on your house and that you are running this at the same pressure that the appliances use inside your house. If this is the case I would look at separating the two lines and using a higher pressure regulator for the furnace than what is used for your house.
4. You should consider making a metal band to go around the lid of your furnace that has handles on it. This can easily be done by taking a piece of a metal can and cutting it the same height as your top on your furnace. Attach a couple of handles on it similar to what mine has with rivets or screws. Then take and drill 4 - 6 holes in the metal band and mark on the cement top where the holes are and then drill these out smaller than the screws that you can take and drill into the metal to attach to the top. This will make it a lot safer to deal with the top when you want to remove it.
In the first photo you will see that the exhaust opening is a lot smaller than in your furnace. The opening is 2" across and the two side slot are 2" long as well. Most of the time when I am running the furnace I will put a brick over the side slots just to retain heat and not use as much fuel. It doesn't really make much of a difference when I close the side slots off on how the furnace operates.
In this second photo you will see that my burner pipe is a 3/4" pipe with a 3/4" x 1-1/2" bell reducer on the end of it for the inflow of air for the fuel mixture. I have seen these furnaces also setup with an added air supply from a compressor or other source to generate higher heat temperatures. But I don't feel that is necessary for this furnace at this point with everything I have used it for
In the third photo you will see that the burner inlet is a little bit more to the side of the furnace than your is but I don't think that will have much of a difference on your furnace. The reason for the side inlet where it is is so that it will create a vortex motion of the flame in the furnace. I think yours is fine where it is.
In this fourth picture you can see a #4 graphite crucible next to a 300ml beaker for size comparison. This furnace will reach an operating temperature hot enough to melt this crucible full of copper powder in roughly 30-45 minutes from a cold start. Once it reaches its melting temperature the copper can be poured and another load added to the crucible and melt the charge in about 10-15 minutes. The furnace does not have to be run at maximum out put to accomplish this. When my furnace is operating you can not touch the sides because of the heat generated, you have to use gloves even when using the handles to remove the top.
Another tip on the crucible is to not use a cheap clay one when running this furnace, if you look at the picture looking down into the furnace you can see that I used a couple of cheap crucible and they failed during the melt. Go ahead and spend the money to get a graphite crucible. The one in the picture is a salamander crucible I purchased on ebay for about $20.00 if I remember correctly.
1. I think you need to upsize your burner pipe to a 3/4" with a bigger bell reducer on the end for incoming air flow.
2. You need to reduce your exhaust opening.
3. I'm also not so sure that your gas pressure might need to be increased at your burner pipe. I am guessing that the propane is being supplied by the tank that you use on your house and that you are running this at the same pressure that the appliances use inside your house. If this is the case I would look at separating the two lines and using a higher pressure regulator for the furnace than what is used for your house.
4. You should consider making a metal band to go around the lid of your furnace that has handles on it. This can easily be done by taking a piece of a metal can and cutting it the same height as your top on your furnace. Attach a couple of handles on it similar to what mine has with rivets or screws. Then take and drill 4 - 6 holes in the metal band and mark on the cement top where the holes are and then drill these out smaller than the screws that you can take and drill into the metal to attach to the top. This will make it a lot safer to deal with the top when you want to remove it.
I will have to try those suggestions. From all I have studied not many people seem to build them this small, that is why I went with a 1/2" build for the burner. I have the pipe here, but need the 3/4" to 1 1/2" reducer. I am running this one from a 20Lb bottle and have just changed to a high pressure regulator. I now have a cold spot in the crucible where the burn makes initial contact. I think I will wait and try to get the 3/4 burner going before fooling with it much more.
Barren Realms 007
In Remembrance
Looks to be a 1/4" brass nipple. The outside diameter is 3/8".
The orifice for propane is normally around a #55 (0.040) to #60 (0.052) drill bit, depending on the burner size.
You can find plans for that burner and many others on the internet. The simpler burners like that one work well if properly tuned.
You can find plans for that burner and many others on the internet. The simpler burners like that one work well if properly tuned.
For decent prices and a wide variety of black iron and brass pipe and fittings, check Zoro.com: Industrial Equipment, Supplies, Tools & MRO Products. My local big box stores only stock the stuff that would commonly be used. Zoro has a much wider selection. I've bought 1-1/2" to 1/2" and 1-1/4" to 1/2" from them. Be sure to look at all the different listings. Some of the reducers are quite short and "blunt". Others are longer and more gradually tapered, and are much better for this use.
Dave
Dave
Thanks Dave, I could use one of those stores closer to home. It will help on another project I have rambling around in my head.
I did find a 1 1/4" x3/4" reducer yesterday and managed to get it set up with a 3/4" pipe. I used 3/8" copper tubing and a 3/64 drill bit for the orifice. It seemed a bit fussy on start up but worked great once it warmed up. After sitting in the furnace for over an hour without melting copper pipe, it hit me why it wasn't melting... . I was running the gas at 1.5 PSI. There is a reason for using a gauge on the adjustable regulator, I just forgot about it at the time. As soon as it hit 5PSI, the copper melted in about 1 minute. Now I am wishing I had cleaned the ash tray of the previous attempted pour as the second attempt of the day would have been nice by its self.
The second attempt was very liquid and poured easy and smoothly. I need to make/buy myself a small mold and learn some more about melting and pouring metal's harder than lead.
Edit: correct measurement
I did find a 1 1/4" x3/4" reducer yesterday and managed to get it set up with a 3/4" pipe. I used 3/8" copper tubing and a 3/64 drill bit for the orifice. It seemed a bit fussy on start up but worked great once it warmed up. After sitting in the furnace for over an hour without melting copper pipe, it hit me why it wasn't melting...
. I was running the gas at 1.5 PSI. There is a reason for using a gauge on the adjustable regulator, I just forgot about it at the time. As soon as it hit 5PSI, the copper melted in about 1 minute. Now I am wishing I had cleaned the ash tray of the previous attempted pour as the second attempt of the day would have been nice by its self. The second attempt was very liquid and poured easy and smoothly. I need to make/buy myself a small mold and learn some more about melting and pouring metal's harder than lead.
Edit: correct measurement
Barren Realms 007
In Remembrance
Cut you a piece of angle iron and then cut some end plates for it that you can use a C clamp to hold the ends on to use as a mold for a cheap easy fix for now.
I use one similar to this most of the time.
http://www.ebay.com/itm/40-oz-Gold-Bar-Loaf-Cast-Iron-Ingot-Mold-Scrap-Silver-20-oz-Copper-Aluminum-/311530782533?hash=item4888ae7f45:g:7r4AAOSwqrtWn7nT
I use one similar to this most of the time.
http://www.ebay.com/itm/40-oz-Gold-Bar-Loaf-Cast-Iron-Ingot-Mold-Scrap-Silver-20-oz-Copper-Aluminum-/311530782533?hash=item4888ae7f45:g:7r4AAOSwqrtWn7nT
That ingot mold is nice. I had thought it a bit big, but these little crucibles will hold more weight than I thought. I ran a small experiment today and found at 1.5PSI for 20 minutes, then 3.5 for another 20 minutes then on up to 5PSI I will have my first melted copper (without stressing the furnace too much) in about 45 to 50 minutes. Like Frank mentioned I found my second batch to melt in 10 to 15 minutes. The more I learn about this the more fun it seems.
Some time back someone in another post mentioned a corn mold thingy and this gave me an idea.
(found it: Melting silver cement - how to properly do it ? )
My first bars. They are only about 3" long.
Again, Thank You, to everyone involved for making this happen for me. This is one of my bucket list-milestone achievements.
Edited for link
Some time back someone in another post mentioned a corn mold thingy and this gave me an idea.
(found it: Melting silver cement - how to properly do it ? )
My first bars. They are only about 3" long.
Again, Thank You, to everyone involved for making this happen for me. This is one of my bucket list-milestone achievements.
Edited for link
Barren Realms 007
In Remembrance
Glad the changes are working for you.
Where is that copper cemented from? If I didn't know better looking at the bars it looks like you have PM's in the bars, but that could just be rust I am looking at.
Where is that copper cemented from? If I didn't know better looking at the bars it looks like you have PM's in the bars, but that could just be rust I am looking at.
Barren Realms 007
In Remembrance
Ok, so there is a chance that you have PM's in this then.
Some improvement. On my third try with mixed copper and mixed magnetic parts from incinerated IC's. (I only used the internal parts of the IC's with the bars from my previous picture). I still learned a lot from this test batch and I am pleased with the results, for now.
This picture, if I am right, shows what I think is termed as a "mat". The crusty looking parts of iron that layered between the borax and the copper layer.
The bottom. The two beads came from my second attempt. Not quite successful but better than my first.
This picture, if I am right, shows what I think is termed as a "mat". The crusty looking parts of iron that layered between the borax and the copper layer.
The bottom. The two beads came from my second attempt. Not quite successful but better than my first.
Barren Realms 007
In Remembrance
Hey you're getting there and making headway. Cool job. Just be patient and don't try to rush things. :mrgreen:
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