Author Topic: Sawed off cupola  (Read 58497 times)

Offline vtsteam

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Re: Sawed off cupola
« Reply #175 on: July 02, 2013, 08:18:58 PM »
And silver brazed together:

« Last Edit: January 07, 2018, 10:28:39 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #176 on: July 02, 2013, 08:24:48 PM »
Here are various mods. The .024" Mig tip has been re-shaped to a bullet outer profile, and the threads at the base turned off to fit inside a 1/4" copper tube. This will be silver brazed in. It will create a compressed air jet to blow oil out through the plug orifice -- something like an injector.

The modded brass plug orifice has been countersunk 60 degrees on the inside, and has a 3/32" hole for exit of the oil and air mix.

Also shown is the 1/4" iron pipe extension that has been brazed to the Tee and threaded internally to take the orifice plug.


« Last Edit: January 07, 2018, 10:29:25 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #177 on: July 02, 2013, 08:31:42 PM »
Here's the completed assembly. The compressed air comes in on the left line. It travels through the coaxial 1/4" copper line and mig tip. The oil comes in on the right line. It fills the 1/4" iron pipe section. The gap between the mig tip and brass plug pipe orifice is adjustable by screwing the plug in. The compressed air @ 30 psi forces the oil in the gap through the orifice and atomizes it.

Not shown is the outer 1-1/4 tube housing that is inserted into the furnace and forms the duct for the blower.

I hope this new burner will outperform the old one with a full spray, and eliminate the drip.


« Last Edit: January 07, 2018, 10:33:38 AM by vtsteam »
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Offline ironman

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Re: Sawed off cupola
« Reply #178 on: July 02, 2013, 08:42:18 PM »
It is great to see you melting cast iron. You have joined a very exclusive club!

Does this mean that the cupola iron melting idea is gone forever?  :bow:  :bow:  :bow:  :clap:  :clap:  :clap:

Offline vtsteam

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Re: Sawed off cupola
« Reply #179 on: July 02, 2013, 09:17:50 PM »
It is great to see you melting cast iron. You have joined a very exclusive club!

Does this mean that the cupola iron melting idea is gone forever?  :bow:  :bow:  :bow:  :clap:  :clap:  :clap:

No Ironman, I almost made up the 10" cupola furnace extension today, but decided to upgrade the oil burner instead because it was, again, RAINING. And I didn't want to weld in the rain.

I have never seen a wetter late spring and early summer. It rained right after my first iron pour, and has rained every day since and is predicted to rain through the end of the week. Two year ago we had a drought and were without water for two months. I'm not complaining but.......crikey!

I'm also going to reduce the size of the tuyere to fit the oil burner but add a second one opposite for use when a cupola -- two tuyeres will help prevent the slope of the charcoal that the iron slid down prematurely to tuyere level on my first try -- and the doubling of the bed height should help, too.
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Offline vtsteam

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Re: Sawed off cupola
« Reply #180 on: July 03, 2013, 05:10:08 PM »
Rain held off. Started on the second tuyere. Decided to make both 2" dia and line with steel tube. So I cut two sections of tube with angled ends. They will both mount pointing downward towards the center of the barrel,

Here I'm drilling out the location for the second tuyere opposite the original one with a carbide masonry drill. It went right through the stainless steel jacket and easily drilled through the firebrick lining. Took about 5 minutes to do.



« Last Edit: January 07, 2018, 10:34:53 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #181 on: July 03, 2013, 05:13:20 PM »
And here is the tubing liner installed:


« Last Edit: January 07, 2018, 10:35:30 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #182 on: July 03, 2013, 05:16:47 PM »
And the new liner on the first tuyere. Black stain is soot from the oil burner drip. I had to chisel the firebrick a little on this side to be able to angle the tuyere downward. The upper hole is from a fitting removed from the original vacuum cleaner that forms the housing.


« Last Edit: January 07, 2018, 10:36:06 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #183 on: July 03, 2013, 05:20:25 PM »
And finally today I bent up and welded together a ten inch cupola extension.

To do: Line the extension, extend the top lift rod, make some sort of wind manifold -- not sure if it will be a full fledged wind belt or not.

The furnace as it stands now:




« Last Edit: January 07, 2018, 10:36:45 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #184 on: July 05, 2013, 04:08:29 PM »
Today I lined the cupola furnace extension. I was a little concerned about building it with firebrick on the table and then transporting it to the furnace. Not much wet strength compared to the weight, and I could imagine the whole thing collapsing out of the steel ring. But I couldn't dry it very easily without heating it on the furnace, so it did have to be moved.

Finally I decided to just build it right on top of the furnace. But to prevent sticking the wet clay to the furnace top, I put a layer of cardboard between them. I hoped the cardboard would burn out once fired.







« Last Edit: January 07, 2018, 10:37:26 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #185 on: July 05, 2013, 04:17:50 PM »
A base layer of fire clay and sand was put down and the firebricks were pressed into ring.

The brick edges were buttered with premix refractory furnace cement -- the type with sodium silicate in it. I had a gallon of the stuff, and though it isn't refractory enough to handle iron melting temperatures, the outer edges of the furnace probably never have reached as much as 400 F.

But one great advantage of the furnace cement is that it is a very good adhesive compared to the clay/sand mix. So I was able to effectively glue the brick to the steel outer ring with a good bond, and I hoped this would help prevent any collapse of the extension lining when it is finally heat cured.


« Last Edit: January 07, 2018, 10:38:21 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #186 on: July 05, 2013, 04:20:15 PM »
Adding more firebrick. The spaces between the bricks were filled with clay sand mix and chunks of broken up firebrick. Each section was progressively filled and rammed.


« Last Edit: January 07, 2018, 10:38:59 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #187 on: July 05, 2013, 04:26:10 PM »
And finally the extension lining was completed with a cap of fireclay and sand.

After this photo, I loaded the cupola with wood and kept the fire burning for 4 hours. The draft through the 2 new 2" dia tuyeres was sufficient for a good draw without a blower. Toward the end of the burn, I covered the cupola with the lid. I haven't tried to remove the extension yet as it is very hot, but I think it baked well.


« Last Edit: January 07, 2018, 10:39:38 AM by vtsteam »
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Rob.Wilson

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Re: Sawed off cupola
« Reply #188 on: July 06, 2013, 03:12:54 AM »
Hi Steve


You have been busy  :thumbup:  , nice job making the extension piece , looks like you will have room for allot more fuel .


Rob 

Offline vtsteam

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Re: Sawed off cupola
« Reply #189 on: July 06, 2013, 09:07:17 AM »
Thanks Rob!  :beer:  Your encouragement has kept me going on this thing.  :nrocks:

Guess I've got to make more charcoal now.

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Offline vtsteam

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Re: Sawed off cupola
« Reply #190 on: July 06, 2013, 08:22:45 PM »
Family and company for last couple days for the 4th, so not much time for the furnace. But pulled the extension off this morning to have a peek. Here it is. Cardboard pattern and wrinkles were reproduced faithfully in  the refractory.





I trimmed out the excess flash in the center and smoothed the whole with a fire brick used as a sanding block. Very effective!

I hope to make some charcoal tomorrow, and try to work out the air supply for the two tuyeres.
« Last Edit: January 07, 2018, 10:40:21 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #191 on: July 08, 2013, 02:03:46 PM »
Twin pipes:

« Last Edit: January 07, 2018, 10:41:03 AM by vtsteam »
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Offline vtsteam

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Re: Sawed off cupola
« Reply #192 on: July 08, 2013, 06:10:53 PM »
Trying out tubing hook up lengths. The nice thing about PVC pipe is that it is the same size as iron pipe, so plastic solvent glue type fittings are a good firm slip fit on metal. The I.D. also fit some flexible hose I had, and this in turn fits my small shop vacuum. So This looks like it will work.

I chose plastic because a welded steel crossover wouldn't have been removable (to switch over to the oil fired burner.) Also the weight of  iron pipework needs lots of external support.

I made up the Y fitting by splitting two elbows and gluing the halves together (I didn't have a Tee in the junk box). But I will probably replace that with a manifold box with an external bleed shutter so i can control the blast.

Anyway, this gives me an idea how things will eventually be arranged.

« Last Edit: January 07, 2018, 10:41:48 AM by vtsteam »
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Offline doubleboost

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Re: Sawed off cupola
« Reply #193 on: July 08, 2013, 06:15:11 PM »
This is looking great
Like a big stethoscope  :lol: :lol: :lol: :headbang: :headbang: :) :)
John

Offline vtsteam

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Re: Sawed off cupola
« Reply #194 on: July 08, 2013, 08:45:50 PM »
Thanks John!  :beer: :beer:

I guess the blower is the heartbeat of the furnace. Especially when it was bellows!  Pumping that for a couple hours must have been interesting!  :whip:
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Offline awemawson

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Re: Sawed off cupola
« Reply #195 on: July 09, 2013, 03:58:03 AM »
I have visions of you stopping the blower, the tuyers heating up and the plastic fittings dribbling down  :lol:
Andrew Mawson
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Offline vtsteam

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Re: Sawed off cupola
« Reply #196 on: July 09, 2013, 11:59:46 AM »
I don't think that will be a problem for a number of reasons awemawson including the fact that the plastic slip fittings are removable, your explanations of strict one way convection in our earlier discussions of chimney function, and the obvious natural draft of this cupola previously mentioned here, but never say never!   If they melt, I can always replace them with metal.  :)
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Offline vtsteam

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Re: Sawed off cupola
« Reply #197 on: July 09, 2013, 06:05:37 PM »
Mmmmmmm, charcoal!





About 9 gallons above, representing the usable yield from one burn in the charcoal barrel, minus fines and brands.

The cupola holds 4.5 gallons. I'm guessing 18 gallons should be a minimum to have on hand before trying a melt.

The barrel reloaded for another burn tomorrow morning:


« Last Edit: January 07, 2018, 10:43:52 AM by vtsteam »
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Offline NeoTech

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Re: Sawed off cupola
« Reply #198 on: July 10, 2013, 06:51:28 AM »
Is there any thread on your charcoal making ... bucket..  I have seen many versions of making charcoal but the almost always have a double walled solution.. your seems to be open fired from below.. ?
Machinery: Optimum D320x920, Optimum BF20L, Aciera F3. -- I have not failed. I've just found 10,000 ways that won't work. http://www.roughedge.se/blogg/

Offline vtsteam

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Re: Sawed off cupola
« Reply #199 on: July 10, 2013, 08:04:54 AM »
Here you go, NeoTech:

http://madmodder.net/index.php/topic,8484.0.html

It actually fires all through, just lit from below. It's actually very similar to existing charcoal methods with a lifted metal kiln ring and propped up metal lid -- though considerably smaller than those!

Here's a video by Amy Smith that shows the method using corn stalks, and also simple briquetting:


I love it when a Plan B comes together!
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